Image forming apparatus

Abstract

To provide sealing capability of reducing toner scattered inside a device due to an air flow that cools exposure means.SOLUTION: An image forming device comprises: a photoreceptor unit that has a photoreceptor; exposure means that forms a latent image on the photoreceptor; development means that develops the latent image formed on the photoreceptor by a toner; a photoreceptor support member that guides the photoreceptor unit along an axial line direction of the photoreceptor and removably supports it; a development support member that guides the development means along the axial line direction and removably supports it; an exposure support member that is disposed between the photoreceptor support member and the development support member and has an opening that communicates with the exposure means, and that is moved, integrally with the exposure means, to an exposure position where the photoreceptor is exposed, and to a retreat position where the photoreceptor is retracted from the exposure position; an exposure cooling unit that communicates with the opening of the exposure support member, and configured to cool the exposure means by an air flow through the opening of the exposure support member; and a sealing member that seals, at the exposure position, a gap between the exposure support member and the development support member and a gap between the exposure support member and the photoreceptor support member, the sealing member being disposed at a prescribed angle with respect to a movement direction of the exposure support member.SELECTED DRAWING: Figure 22

Description

Technical Field

[0001] The present invention relates to an image forming apparatus including an exposure head that exposes a photoreceptor.

Background Art

[0002] Conventionally, as a technique related to an exposure head used in an electrophotographic image forming apparatus, the technique described in Patent Document 1 is known.

[0003] The exposure head described in Patent Document 1 includes a substrate on which a plurality of light emitting elements are arranged along the axial direction of the photoreceptor, a lens that condenses light emitted from the plurality of light emitting elements, and a holder that holds the substrate and the lens. The exposure head exposes the photosensitive drum by condensing the light emitted from the plurality of light emitting elements through the lens.

[0004] Therefore, the exposure head described in Patent Document 1 is disposed close to the photoreceptor together with a developing device that develops a latent image formed on the photoreceptor with toner. Therefore, the exposure head is disposed close to the developing device.

[0005] The exposure head includes an LED (Light Emitting Diode) as a light emitting element. Alternatively, some include an organic EL (Organic Electro Luminescence) as a light emitting element. Organic EL is sometimes called OLED (Organic Light Emitting Diode).

[0006] The exposure head is known to dissipate heat according to the length of the light emission time and the magnitude of the light emission amount of such a light emitting element. Since the exposure head is disposed close to the developing device that attaches toner to toner to the photoreceptor as described above, cooling means is often required to suppress the influence of the heat from the exposure head on the toner.

[0007] Furthermore, since the photoreceptor is a consumable item, it is designed to be removable for replacement and maintenance. However, as mentioned above, the exposure head is positioned close to the photoreceptor, and if left in that position, the photoreceptor and the exposure head may come into contact, potentially damaging one or both. Therefore, it is desirable to have a mechanism for removing the exposure head from the photoreceptor.

[0008] Patent Document 1 discloses an exposure head attachment / detachment mechanism comprising a mechanism support portion positioned directly below the entire longitudinal range of the exposure head, and a link member held above it. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2019-3110 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] However, in the configuration disclosed in Patent Document 1, the light-emitting element, which is a heat source, is surrounded by a holder that holds the substrate on which the light-emitting element is mounted and a mechanism support part located directly below the recording head, making it difficult to directly direct cooling airflow to the heat source.

[0011] Furthermore, when an airflow for cooling is formed around the exposure head, there is a problem in that the toner from the photoreceptor and developing device, which are located close to the exposure head, can be scattered into the inside of the device.

[0012] The object of the present invention is to provide an image forming apparatus with sealing properties that reduce toner scattering inside the image forming apparatus due to airflow cooling the exposure head. [Means for solving the problem]

[0013] A typical configuration of the present invention includes a photoreceptor unit having a photoreceptor, an exposure means positioned in close proximity to the photoreceptor and exposing the photoreceptor to form a latent image on the photoreceptor, a developing means for developing the latent image formed on the photoreceptor with toner, a photoreceptor support member that guides the photoreceptor unit along the axial direction of the photoreceptor and detachably supports the photoreceptor unit, a developing support member that guides the developing means along the axial direction of the photoreceptor and detachably supports the developing means, and an opening provided between the photoreceptor support member and the developing support member that communicates with the exposure means. The system comprises: an exposure support member that integrally supports the exposure means and moves integrally with the exposure means to an exposure position for exposing a photoreceptor and a retracted position retracted from the exposure position; an exposure cooling unit that communicates with an opening in the exposure support member and cools the exposure means by airflow through the opening in the exposure support member; and a sealing member that seals the gap between the exposure support member and the developer support member and the gap between the exposure support member and the photoreceptor support member at the exposure position, wherein the sealing member is arranged at a predetermined angle with respect to the direction of movement of the exposure support member. The exposure support member has, through the opening, a first duct wall having a first inclined surface forming a predetermined angle at a position opposite to the developing support member on one side in a direction perpendicular to the axial direction of the photoreceptor, and a second duct wall having a second inclined surface forming a predetermined angle at a position opposite to the photoreceptor support member on the other side in a direction perpendicular to the axial direction of the photoreceptor, and the sealing member is provided on the first inclined surface and the second inclined surface, respectively, and forms the predetermined angle. It is characterized by the following: [Effects of the Invention]

[0014] According to the present invention, it is possible to provide an image forming apparatus with sealing properties that reduce toner scattering inside the image forming apparatus due to the airflow used to cool the exposure means. [Brief explanation of the drawing]

[0015] [Figure 1] Perspective view of an image forming apparatus [Figure 2] Schematic cross-sectional view of the image forming apparatus in Figure 1. [Figure 3] Schematic cross-sectional view of the image forming apparatus in Figure 1. [Figure 4] Perspective view of an image forming apparatus [Figure 5] Partially enlarged perspective view of an image forming apparatus [Figure 6] Partially enlarged perspective view of an image forming apparatus [Figure 7]Partial enlarged perspective view of an image forming apparatus [Figure 8] Perspective view of a cartridge tray [Figure 9] Perspective view of a cartridge tray [Figure 10] Cross-sectional view of an exposure head [Figure 11] Perspective view of an exposure head [Figure 12] Perspective view of an exposure head [Figure 13] (a), (b), (c) Diagrams showing a substrate in an exposure head, (d), (e) Diagrams showing a lens array [Figure 14] Perspective view of a substrate as seen from the side of the surface (substrate surface) on which LEDs are mounted [Figure 15] Perspective view of a substrate as seen from the side of the surface (substrate back surface) on which connectors are mounted [Figure 16] Perspective view of an exposure head with the substrate assembled to the housing as seen from below [Figure 17] Enlarged view of the connector side of the exposure head in FIG. 16 [Figure 18] Perspective view showing an exposure head with a lens array assembled to the housing in FIG. 16 [Figure 19] Perspective view of the connector side of an exposure head in which the housing and the housing support member are integrally formed as seen from below [Figure 20] Perspective view of a cartridge tray [Figure 21] Bottom view of a cartridge tray and a lifting duct [Figure 22] It is a cross-sectional view taken along the X-X arrow in FIG. 20. [Figure 23] Cross-sectional view taken along the X-X arrow in FIG. 20 [Figure 24] Cross-sectional view taken along the Y-Y arrow in FIG. 20 [Figure 25] Cross-sectional view taken along the Y-Y arrow in FIG. 20 [Figure 26] Cross-sectional view in a direction perpendicular to the optical axis of the exposure cooling air flow [Figure 27] Perspective view of an exposure head, a lifting duct, and a rotating arm [Figure 28]Perspective view of the exposure head, lifting duct, and rotating arm. [Figure 29] Cross-sectional view taken along the EE arrow in Figure 37. [Figure 30] Cross-sectional view taken along the EE arrow in Figure 37. [Figure 31] Side view of the developing stay [Figure 32] Side view of the developing stay [Figure 33] Cross-sectional view taken along arrow XX in Figure 20 [Figure 34] Cross-sectional view taken along arrow AA in Figure 2. [Figure 35] Perspective view of the duct unit [Figure 36] Perspective view of the duct unit from below. [Figure 37] Cross-sectional view of the intake side of the exposure cooling airflow. [Figure 38] Enlarged cross-sectional view of the intake side of the exposure cooling airflow. [Figure 39] Cross-sectional view of the exhaust side of the exposure cooling airflow. [Figure 40] Cross-sectional view of the duct unit just before assembly. [Figure 41] (a), (b) Enlarged cross-sectional view of the positioning shape of the duct unit, (c), (d) Enlarged cross-sectional view of the duct unit just before assembly. [Figure 42] Cross-sectional view taken along the FF arrow in Figure 39. [Figure 43] Cross-sectional view of the photosensitive drum, exposure head, and rotating arm. [Figure 44] Cross-sectional perspective view showing the front positioning of the photosensitive drum and exposure head. [Figure 45] Cross-sectional perspective view showing the positioning of the photosensitive drum and exposure head on the back side. [Figure 46] Perspective view showing the state after the positioning member has been installed. [Figure 47] Perspective view showing the state before the positioning member is installed. [Figure 48] Perspective view showing the shape of the positioning member [Figure 49] Right-side perspective view with the exposure head removed from the lifting duct. [Figure 50] Front cross-sectional view with the exposure head removed from the lifting duct. [Figure 51] Left side perspective view with the exposure head removed from the lifting duct. [Figure 52] Right-side perspective view with the exposure head placed in the lifting duct. [Figure 53] Front cross-sectional view with the exposure head placed in the lifting duct. [Figure 54] Left side perspective view with the exposure head placed in the lifting duct. [Figure 55] Cross-sectional view showing the exposure head placed in the lifting duct. [Figure 56] Perspective view of the vicinity of the conductive member with the exposure head placed in the lifting duct. [Figure 57] Right-side perspective view showing the exposure head attached to the lifting duct. [Figure 58] Left side perspective view showing the exposure head attached to the lifting duct. [Figure 59] Cross-sectional view showing the exposure head attached to the lifting duct. [Figure 60] Enlarged cross-sectional view of the engagement portion shown in Figure 59. [Figure 61] Perspective view of the vicinity of the conductive member with the exposure head attached to the lifting duct. [Figure 62] Right-side cross-sectional view showing the harness opening. [Figure 63] Right-side perspective view of the FFC after excess length processing. [Figure 64] Front cross-sectional view after FFC excess length processing. [Figure 65] Front cross-sectional view showing the state of the FFC in the retracted position. [Modes for carrying out the invention]

[0016] The embodiments for carrying out the present invention will be described below with reference to the drawings. The dimensions, materials, shapes, and relative arrangements of the components described below are not intended to limit the scope of this invention to those unless otherwise specifically stated.

[0017] (Image forming apparatus) First, the schematic configuration of the image forming apparatus 100 will be described using Figures 1, 2, and 3. Figure 1 is a perspective view of the image forming apparatus 100. Figures 2 and 3 are schematic cross-sectional views of the image forming apparatus in Figure 1. The image forming apparatus 100 shown in Figures 1 to 3 is a copier equipped with a reading device, but the embodiment may also be other image forming apparatuses, such as a printer without a reading device. Furthermore, the embodiment is not limited to a color image forming apparatus equipped with multiple photosensitive drums 2 as shown in Figures 2 and 3, but may also be a color image forming apparatus equipped with one photosensitive drum 2 or an image forming apparatus that forms monochrome images.

[0018] The image forming apparatus 100 shown in Figures 2 and 3 includes four image forming units 1Y, 1M, 1C, and 1K (hereinafter collectively referred to simply as "image forming unit 1") that form toner images of yellow, magenta, cyan, and black, respectively.

[0019] Furthermore, the image forming units 1Y, 1M, 1C, and 1K each include a photosensitive drum 2Y, 2M, 2C, and 2K (hereinafter collectively referred to simply as "photosensitive drum 2"), which is an example of a photoreceptor. The photosensitive drum 2 may also be a photosensitive belt.

[0020] Furthermore, the image forming units 1Y, 1M, 1C, and 1K are equipped with charging rollers 3Y, 3M, 3C, and 3K (hereinafter collectively referred to simply as "charging rollers 3") which serve as charging means for charging the photosensitive drums 2Y, 2M, 2C, and 2K, respectively.

[0021] Furthermore, the image forming units 1Y, 1M, 1C, and 1K are equipped with LED (Light Emitting Diode, hereinafter referred to as LED) exposure heads 4Y, 4M, 4C, and 4K (hereinafter collectively referred to simply as "exposure head 4") as exposure means for exposing the photosensitive drums 2Y, 2M, 2C, and 2K.

[0022] Furthermore, the image forming units 1Y, 1M, 1C, and 1K are equipped with developing units 24Y, 24M, 24C, and 24K (hereinafter collectively referred to simply as "developing unit 24"), which are developing means for developing the electrostatic latent image on the photosensitive drum 2 with toner and developing toner images of each color on the photosensitive drum 2. The symbols Y, M, C, and K indicate the color of the toner.

[0023] The image forming apparatus 100 shown in Figures 2 and 3 is an image forming apparatus that employs a so-called "bottom exposure method," in which the photosensitive drum 2 is exposed from below, that is, the exposure head 4 is positioned below the photosensitive drum 2. The following explanation will proceed on the premise of an image forming apparatus employing a bottom exposure method. Although not shown in the figures, an image forming apparatus employing a "top exposure method," in which the photosensitive drum is exposed from above, may also be used as an embodiment.

[0024] The image forming apparatus 100 includes an intermediate transfer belt 9 to which the toner image formed on the photosensitive drum 2 is transferred, and primary transfer rollers 6 (Y, M, C, K) that sequentially transfer the toner image formed on the photosensitive drum 2 to the intermediate transfer belt 9. The intermediate transfer belt 9 is located above the image forming unit 1. In addition to the intermediate transfer method using the intermediate transfer belt 9, a direct transfer method in which the toner image is transferred directly from the photosensitive drum 2 to the paper may also be used.

[0025] Furthermore, the image forming apparatus 100 includes a secondary transfer roller 16 as a transfer means for transferring the toner image on the intermediate transfer belt 9 to the recording paper P transported from the feeding unit 11, and a fuser 19 as a fixing means for fixing the secondary transferred image to the recording paper P.

[0026] Furthermore, the toner bottles 22Y, 22M, 22C, and 22K (hereinafter collectively referred to simply as "toner bottles 22") that contain refill toner for each color are units that can be attached to and replaced by the image forming apparatus 100. The toner bottles 22 are positioned above the intermediate transfer belt 9. The toner bottles 22 supply the appropriate amount of toner to each developing unit of the four image forming sections from the corresponding toner bottles using a toner supply mechanism (not shown) that is not shown.

[0027] The image forming apparatus 100 also includes a feeding unit 11 for feeding recording paper P. The feeding unit 11 has sheet cassettes 12a and 12b, feeding rollers 13a and 13b, and a registration roller 15. The sheet cassettes 12a and 12b are located at the bottom of the image forming unit 1. The recording paper P contained in the sheet cassettes 12a and 12b is fed one sheet at a time by the feeding rollers 13a and 13b and transported to the secondary transfer unit T2 at a predetermined timing by the registration roller 15.

[0028] (Image formation process) Next, the image forming process of the image forming apparatus 100 described above will be briefly explained. The charging roller 3Y charges the surface of the photosensitive drum 2Y. The exposure head 4Y exposes the surface of the photosensitive drum 2Y that has been charged by the charging roller 3Y. As a result, an electrostatic latent image is formed on the photosensitive drum 2Y. Next, the developing unit 24Y develops the electrostatic latent image formed on the photosensitive drum 2Y with yellow toner. The yellow toner image developed on the surface of the photosensitive drum 2Y is transferred onto the intermediate transfer belt 9 by the primary transfer roller 6Y. Magenta, cyan, and black toner images are also formed by a similar image forming process and transferred onto the intermediate transfer belt 9 in a superimposed manner.

[0029] The toner images of each color transferred onto the intermediate transfer belt 9 are transported by the intermediate transfer belt 9 to the secondary transfer section T2. ​​The toner images transported to the secondary transfer section T2 are transferred collectively to the recording paper P transported from the feeding section 11 by the secondary transfer roller 16. The recording paper P on which the toner images have been transferred is transported to the fuser 19. The fuser 19 fixes the toner images to the recording paper P using heat and pressure. The recording paper P that has been fixed by the fuser 19 is discharged by the discharge roller 20 to the discharge tray 21 located above the toner bottle 22.

[0030] (Drum unit and developing unit) The interchangeable drum unit 23 and developing unit 24 in the image forming apparatus 100 of this embodiment will be described as examples.

[0031] The aforementioned photosensitive drum 2 and charging roller 3, together with a cleaning device (not shown), are integrated into a single unit (drum unit, drum cartridge). An example of this configuration will be explained using Figures 4, 5, 6, and 7. Figures 4 and 5 are perspective views showing the schematic structure around the drum unit 23 (Y, M, C, K) and the developing unit 24 (Y, M, C, K) of the image forming apparatus 100. Figure 6 shows how the drum unit 23 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus body. Figure 7 shows how the developing unit 24 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus body.

[0032] The image forming apparatus 100 is fitted with drum units 23Y, 23M, 23C, and 23K (hereinafter collectively referred to simply as "drum unit 23"), each equipped with a photosensitive drum 2. The drum unit 23 is a cartridge that can be replaced by a user or maintenance worker. The drum unit 23 rotatably supports the photosensitive drum 2. Specifically, the photosensitive drum 2 is rotatably supported by the frame of the drum unit 23. The drum unit 23 may not be configured to include a charging roller 3 or a cleaning device.

[0033] Furthermore, the image forming apparatus 100 is equipped with developing units 24Y, 24M, 24C, and 24K (hereinafter collectively referred to simply as "developing unit 24"), which are separate from the drum unit 23, which is the photoreceptor unit. The developing unit 24 comprises developing sleeves 5Y, 5M, 5C, and 5K (hereinafter collectively referred to simply as "developing sleeve 5"), which serve as developer carriers for holding the developer, and screws 7Y, 7M, 7C, and 7K (hereinafter collectively referred to simply as "screw 7") for supplying the developer to the developing sleeves 5 and agitating the developer. The developing unit 24 is a cartridge in which the developing sleeves 5 and screws 7 are integrated, and as shown in Figures 5 and 7, it is removed from the main body of the image forming apparatus 100 and replaced by an operator.

[0034] Inside the developing unit 24, toner is circulated and transported at high speed by the screw 7. The rotation speed of the screw 7 is very high relative to the rotation speed of the developing sleeve 5 and the photosensitive drum 2, ensuring that the coating on the developing sleeve 5 is even and uniform.

[0035] Furthermore, the image forming apparatus 100 is equipped with a cartridge tray 30 (30Y, 30M, 30C, 30K) for each image forming section (see Figures 8 and 9). The drum unit 23 and the developing unit 24 are supported by the cartridge tray 30 for each image forming section, guided in the axial direction of the photosensitive drum, and inserted into and removed from the main body of the image forming apparatus 100.

[0036] The image forming apparatus 100 also includes a front plate 100F made of sheet metal and a rear plate 100B also made of sheet metal (see Figure 34). The front plate 100F is a side wall provided on the front side of the image forming apparatus 100. The front plate 100F forms part of the housing of the main body of the image forming apparatus 100 on the front side. The rear plate 100B is a side wall provided on the rear side of the image forming apparatus 100. The rear plate 100B forms part of the housing of the main body of the image forming apparatus 100 on the rear side. The front plate 100F and the rear plate 100B are arranged facing each other on one side and the other side in the axial direction of the photosensitive drum, and a sheet metal beam (not shown) bridges between them. The front plate 100F, the rear plate 100B, and the beam (not shown) each constitute part of the frame (housing) of the image forming apparatus. In this embodiment, with respect to the image forming apparatus or its components, the front side or near side is the side from which the drum unit 23 and the developing unit 24 are inserted into and removed from the main body of the image forming apparatus 100.

[0037] The cartridge tray 30 is attached to the front plate 100F (see Figure 34) on one end and to the rear plate 100B (see Figure 34) on the other end, in the axial direction of the photosensitive drum. The cartridge tray 30 will be described later.

[0038] The drum unit 23 and the developing unit 24 deteriorate due to repeated image formation processes, and therefore take the form of units (cartridges) that can be replaced or removed for maintenance.

[0039] Figure 3 shows the arrangement of the drum unit 23, developing unit 24, and exposure head 4 when they are being replaced or attached / detached. In the image forming apparatus shown in Figure 3, unlike the image forming apparatus shown in Figure 2, the developing unit 24 and exposure head 4 are retracted from and separated from the photosensitive drum 2.

[0040] This is because, as shown in Figure 2, if the developing unit 24 and exposure head 4 are positioned in close proximity to the photosensitive drum 2, dynamic interference during unit attachment and detachment may cause damage to each unit, or even make it impossible to remove the unit.

[0041] Therefore, when attaching or detaching the unit, the developing unit 24 and the exposure head 4 are moved away from the photosensitive drum 2 and separated from each other by a retraction mechanism consisting of the developing stay 31, the rotating arm 65, and the lifting duct 69, as described later, as shown in Figure 3.

[0042] The drum unit 23 and the developing unit 24 are inserted and removed from the front side of the image forming apparatus 100, and mounted in predetermined positions (mounting positions) on the main body of the image forming apparatus 100.

[0043] The image forming apparatus 100 is equipped with inner doors 102Y, 102M, 102C, and 102K (hereinafter collectively referred to simply as "inner doors 102") that cover the front sides of both the drum unit 23 and the developing unit 24 mounted in their respective positions. As shown in Figures 8 and 9, 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.

[0044] The inner door 102 is a necessary component for protecting each unit and making it difficult for the photosensitive drum 2 to be exposed to light outside of the image formation process, and is positioned opposite the front of the unit of each color in the direction in which it is attached and detached.

[0045] Furthermore, a front cover 101, which forms the exterior of the image forming apparatus 100, is provided on the front side of the apparatus. One end of the front cover 101 is fixed to the front side of the apparatus body of the image forming apparatus 100 by a hinge, and the hinge allows it to rotate relative to the apparatus body of the image forming apparatus 100. The front cover 101 is located in front of the inner door 102 in the axial direction of the photosensitive drum. In the closed state shown in Figure 1, the front cover 101 covers the entire array of inner doors 102 arranged in the left-right direction, forming the exterior of the front side of the apparatus.

[0046] Therefore, the replacement of the drum unit 23 and the developing unit 24 is performed by an operator using the following procedure. The operator opens the front cover 101 as shown in Figure 4, then opens the inner door 102 as shown in Figure 5, and removes the drum unit 23 (Figure 6) or developing unit 24 (Figure 7) from inside the device. Then, the operator inserts the new drum unit 23 or developing unit 24, closes the inner door 102, and then closes the front cover 101 to complete the replacement.

[0047] The retraction mechanism for the developing unit 24 and exposure head 4 is linked to the opening of the inner door 102, retracting the developing unit 24 and exposure head 4 from the photosensitive drum 2. This retraction mechanism (developing stay 31, rotating arm 65, and lifting duct) will be described later.

[0048] In the following explanation, the front side of the device is defined as the front (front or front) side, and the rear side is defined as the rear (back or rear) side. Furthermore, with respect to the photosensitive drum 2K on which the electrostatic latent image of the black toner is formed, the side on which the photosensitive drum 2Y on which the electrostatic latent image of the yellow toner is formed is defined as the left side. With respect to the photosensitive drum 2Y on which the electrostatic latent image of the yellow toner is formed, the side on which the photosensitive drum 2K on which the electrostatic latent image of the black toner is formed is defined as the right side. In addition, the direction perpendicular to the front-to-back and left-to-right directions defined here, and vertically upward, is defined as the upward direction, and the direction perpendicular to the front-to-back and left-to-right directions defined here, and vertically downward, is defined as the downward direction. The defined front direction F, rear direction B, right direction R, left direction L, upward direction U, and downward direction D are shown in Figure 1.

[0049] Furthermore, the axial direction of the photosensitive drum 2 as described below coincides with the front-to-back direction (front-to-back direction) shown in Figure 1. Similarly, the longitudinal direction of the exposure head 4 also coincides with the front-to-back direction shown in Figure 1. In other words, the axial direction of the photosensitive drum 2 and the longitudinal direction of the exposure head 4 are the same direction. Also, in the axial direction of the photosensitive drum 2, one end refers to the front side as defined here, and the other end refers to the rear side as defined here. The same applies to the front and rear ends in the front-to-back direction. In the left-to-right direction, one end refers to the left side as defined here, and the other end refers to the right side as defined here.

[0050] (Exposure head) Next, the exposure head 4 will be described using Figures 10 to 19. Figure 10 is a schematic cross-sectional view of the exposure head 4 provided in the image forming apparatus of this embodiment. Figure 11 is a perspective view of the exposure head 4 from above. Figure 12 is a perspective view of the exposure head 4 from below.

[0051] The exposure head 4 has an elongated shape (longitudinal shape) that extends in the axial direction of the photosensitive drum 2. The exposure head 4 comprises a substrate 50, a light-emitting element mounted on the substrate 50, a lens array 52, and a holding member that holds the substrate 50 and the lens array 52. ​​The holding member has a housing 54, which will be described later, and a housing support member 55 that supports the housing 54. Here, the exposure head 4 is equipped with an LED 51 (Light Emitting Diode) as a light-emitting element that emits light.

[0052] (Substrate and lens array) Here, the substrate 50 and lens array 52 of the exposure head 4 will be described using Figures 13, 14, and 15. First, the substrate 50 will be described. Figure 13(a) is a schematic perspective view of the substrate 50. Figure 13(b) shows the arrangement of multiple LEDs 51 provided on the substrate 50, and Figure 13(c) is an enlarged view of Figure 13(b). Figure 14 is a perspective view of the substrate seen from the side on which the LEDs are mounted (the surface of the substrate). Figure 15 is a perspective view of the substrate seen from the side on which the FFC connector is mounted (the back of the substrate). In the figures, one side of the arrow indicates the front side of the image forming apparatus 100, and the other side indicates the rear side of the image forming apparatus 100.

[0053] An LED chip 53 is mounted on the circuit board 50. As shown in Figures 13(a), 14, and 15, the LED chip 53 is provided on one side of the circuit board 50, and a long FFC connector 57 is provided on the other side. Here, one side of the circuit board 50 is the side on which the LED chip 53 is provided (top side, front side). The other side of the circuit board is the side opposite to the side on which the LED chip 53 is provided (bottom side, back side).

[0054] The FFC connector 57 is mounted on the other side (bottom surface, back surface) of the substrate 50 such that its longitudinal direction aligns with the longitudinal direction of the substrate 50. The long FFC connector 57 is located on the front side (one side in the longitudinal direction of the substrate 50) of the image forming apparatus 100. 50 Each LED chip 53Wiring is provided for supplying signals. One end of a flexible flat cable 58 (see Figure 26, hereafter referred to as FFC), which is an example of a cable, is connected to the FFC connector 57.

[0055] The control circuit section of the image forming apparatus 100 is provided with a circuit board (not shown) that includes a control unit and a connector. The other end of the FFC 58 is connected to this connector. In other words, the FFC 58 electrically connects the circuit board (control circuit section) of the apparatus body to the circuit board 50 of the exposure head 4. Control signals (drive signals) are input to the circuit board 50 of the exposure head 4 from the control circuit section of the apparatus body of the image forming apparatus 100 via the FFC 58 and the FFC connector 57. The control signals are transferred to each LED chip 53. The LED chips 53 are driven (light up, turn off) by the control signals input to the circuit board 50.

[0056] The LED chip 53 mounted on the substrate 50 will be described in more detail. As shown in Figures 13(b) and 13(c), 29 LED chips 53-1 to 53-29, each containing multiple LEDs 51 (an example of a light-emitting element), are arranged on one side of the substrate 50. Each LED chip 53-1 to 53-29 has 516 LEDs 51 arranged along its longitudinal direction. In the longitudinal direction of the LED chip 53, the distance k2 between the centers of adjacent LEDs 51 corresponds to the recording resolution of the image forming apparatus 100. Since the recording resolution of the image forming apparatus 100 in this embodiment is 1200 dpi, the LEDs 51 in the longitudinal direction of the LED chips 53-1 to 53-29 are arranged such that the distance k2 between the centers of adjacent LEDs 51 is 21.16 μm. Therefore, the exposure range of the exposure head 4 in this embodiment is approximately 314 mm. The photosensitive layer of the photosensitive drum 2 is formed to be 314 mm or longer in the axial direction. Since the length of the long side of A4 size recording paper and the length of the short side of A3 size recording paper are 297 mm, the exposure head 4 in this embodiment has an exposure range capable of forming images on A4 size and A3 size recording paper.

[0057] LED chips 53-1 to 53-29 are arranged in a staggered pattern along the axis of the photosensitive drum 2. Specifically, LED chips 53-1 to 53-29 are arranged alternately in two rows along the axis of the photosensitive drum 2. That is, as shown in Figure 13(b), counting from the left, odd-numbered LED chips 53-1, 53-3, ... 53-29 are mounted in a single row along the longitudinal direction of the substrate 50. Also, counting from the left, even-numbered LED chips 53-2, 53-4, ... 53-28 are mounted in a single row along the longitudinal direction of the substrate 50. The LED chips 53 are arranged in this manner. As a result, as shown in Figure 13(c), the distance k1 between the centers of LEDs 51 located at one end of one LED chip 53 and the other end of the other LED chip 53 in the longitudinal direction of the LED chip 53 can be made equal to the distance k2 between the centers of adjacent LEDs 51 on a single LED chip 53.

[0058] In this embodiment, the light-emitting element is a semiconductor LED, which is a light-emitting diode, but it may also be an OLED (Organic Light Emitting Diode). This OLED is also called organic EL (Organic Electro-Luminescence) and is a current-driven light-emitting element. OLEDs are, for example, TFTs (Thin Film) पाल They are arranged in a line on the circuit board along the main scanning direction (the axial direction of the photosensitive drum 2) and are electrically connected in parallel by power supply wiring also provided along the main scanning direction.

[0059] Next, the lens array 52, which is a collection of lenses, will be described. Figure 13(d) is a schematic diagram of the lens array 52 as seen from the photosensitive drum 2 side. Figure 13(e) is a schematic perspective view of the lens array 52. ​​As shown in Figure 13(d), the lens array 52 focuses the light emitted from the light-emitting element onto the photosensitive drum 2. The lens array 52 is a collection of lenses having multiple lenses. These multiple lenses are arranged in two rows along the arrangement direction of the multiple LEDs 51. Each lens is arranged alternately such that one lens from the other row is positioned so as to be in contact with both adjacent lenses in the arrangement direction of the lenses in one row. Each lens is a cylindrical glass rod lens and has a light incident surface 52b into which light emitted from the LED 51 enters, and a light exit surface 52a into which light incident from the light incident surface exits (see Figure 10). Note that the material of the lens is not limited to glass, but may also be plastic. The shape of the lens is not limited to a cylinder, but may also be a polygonal prism such as a hexagonal prism.

[0060] The dotted line Z shown in Figure 13(e) indicates the optical axis of the lens. The exposure head 4 is moved in a direction roughly aligned with the optical axis of the lens indicated by the dotted line Z (hereinafter also referred to as the optical axis direction) by a retraction mechanism (rotating arm 65 and lifting duct 69 in Figures 24 and 25), which will be described later. The optical axis of the lens here refers to the line connecting the center of the light-emitting surface of the lens and the focal point of the lens. The lens array 52 is a lens assembly having multiple lenses, and the aforementioned "optical axis" refers to the optical axis of any of these multiple lenses. Here, strictly speaking, the multiple lenses in the lens array 52 may be slightly tilted relative to each other. This is due to tolerances during assembly. However, deviations of this magnitude will not be considered when defining the direction of the optical axis. Therefore, the optical axes of each of the multiple lenses are considered to be in the same direction. The lens array 52 has the role of focusing the light emitted from the LED 51 onto the surface of the photosensitive drum 2.

[0061] The lens array 52 is mounted to the housing 54 during the assembly of the exposure head 4 such that the distance between the light-emitting surface of the LED 51 and the light-incident surface of the lens is approximately equal to the distance between the light-emitting surface of the lens and the surface of the photosensitive drum 2.

[0062] (Enclosure) As shown in Figure 10, the housing 54 holds the lens array 52 and the substrate 50. In this embodiment, the housing 54 is a metal component formed by bending a plate material that has been plated, such as a galvanized steel sheet or a cold-rolled steel sheet.

[0063] As mentioned above, the casing 54 is made of metal. For example, the casing 54 is formed into a U-shape by press-forming a sheet metal such as a thin iron plate. The shape of the casing 54 will be described below.

[0064] As shown in Figure 10, the housing 54 has a flat portion (opposing surface) 54U into which a first opening 54a into which the lens array 52 is inserted is formed. The flat portion 54U faces the photosensitive drum 2 in the optical axis direction of the lenses of the lens array 52. ​​Note that this flat portion 54U is not limited to a flat surface, but may be a slightly curved surface. The housing 54 also has an extension portion 54R that extends from one side in the short direction of the flat portion 54U toward away from the photosensitive drum 2. The housing 54 also has an extension portion 54L that extends from the other side in the short direction of the flat portion 54U toward away from the photosensitive drum 2.

[0065] The extensions 54R and 54L form a substrate support portion in the housing 54 for supporting the substrate 50 inserted through the second opening 54b. 54U The substrate support portion (extension portion 54R, 54L) is an integral part, forming a housing 54 that holds the lens array 52 and the substrate 50, and its cross-section is formed in a substantially U-shape. Because the housing 54 is formed in a substantially U-shape, a second opening 54b is formed on the side opposite to the flat portion 54U. The second opening 54b is formed between the flat portion 54U and the substrate support portion (extension portion 54L, 54R) that extends away from the photosensitive drum.

[0066] The substrate 50 is inserted through the second opening 54b, that is, from the bottom of the U-shaped housing 54, and bonded to the inside of each substrate support portion (the inside of the extension portion 54L and the inside of the extension portion 54R) with adhesive. Note that the position of the substrate 50 in the focal direction is determined by a jig (not shown), so the exposure head 4 does not have a means for positioning the substrate 50 in the focal direction.

[0067] Furthermore, the lens array 52 is also inserted into the first opening 54a formed in the flat section 54U and then bonded to the flat section 54U with adhesive. The lens array 52 is fixed to the flat section 54U (housing 54) after its position and tilt in the focal direction have been adjusted using a jig so that the distance in the focal direction between the lens array 52 and all the LED chips 53 mounted on the substrate 50 is a predetermined value. The lens array 52 is also fixed to the flat section 54U with adhesive at multiple locations in the longitudinal direction. In other words, the exposure head 4 of this embodiment has multiple bonding locations in the longitudinal direction of the flat section 54U for bonding and fixing the lens array 52 inserted into the first opening 54a to the flat section 54U.

[0068] After the substrate 50 and lens array 52 are positioned and fixed relative to the housing 54, the gap between the substrate 50 inserted into the second opening 54b and the housing 54 (extensions 54L, 54R) is sealed longitudinally with a sealant 59, as shown in Figures 16 and 17. Figure 16 is a perspective view from below the exposure head 4 showing the substrate 50 with the LED 51 mounted on it assembled to the housing 54. Figure 17 is an enlarged view of the front of the exposure head shown in Figure 16. This prevents the LED 51 from being contaminated by toner or dust from the outside. Here, the sealant 59 only seals the gap (boundary) between the substrate 50 and the housing 54, and most of the FFC connector 57 and the substrate 50 are exposed.

[0069] Similarly, a sealant 59 is applied to the gap between the lens array 52 inserted into the first aperture 54a and the housing 54 (flat portion 54U), and the gap is sealed longitudinally by the sealant 59 as shown in Figure 18. Figure 18 is a perspective view of the exposure head 4 with the lens array 52 assembled to the housing 54. More specifically, as shown in Figure 10, the sealant 59 seals the gap between the side wall of the lens array 52 along the longitudinal direction of the housing 54 and the edge of the first aperture 54a. This reduces the possibility that dust such as toner will flow in through the gap between the side wall of the lens array 52 and the first aperture 54a, and that the light emitted from the LED 51 will be blocked by the dust. Naturally, the gap sealed by the sealant 59 is not only the gap between one side wall of the lens array 52 and the edge of the first aperture 54a, but also the gap between the other side wall of the lens array 52 and the edge of the first aperture 54a. The other side wall of the lens array 52 refers to the side wall opposite to the one side wall of the lens array 52. ​​Here too, the gap (boundary) between the housing 54 and the lens array 52 is sealed with a sealant 59. This prevents the LED 51 from being contaminated by toner or dust from the outside.

[0070] As described above, the substrate 50 and the lens array 52 are held by the housing 54, so the LED 51 and the incident surface of the lens 52b These two sides face each other. As a result, the light emitted from LED51 is directed towards the incident surface of the lens. 52b It is incident on the lens and the exit surface 52a The light is emitted from the LEDs towards the photosensitive drum 2. In this embodiment, the light emitted from three LEDs 51 (multiple LEDs 51) can pass through the same single lens. Also, even if the light is emitted from only one LED 51, it can pass through multiple lenses because it travels radially. That is, the light emitted from multiple LEDs 51 passes through the lens array 52 (some of the multiple lenses in the lens array 52) to expose the photosensitive drum 2.

[0071] (Housing support member) As shown in Figures 11 and 12, the housing support member 55 supports the housing 54, which holds the substrate 50 and the lens array 52, along its longitudinal direction and is integrally provided with the housing 54. The housing support member 55 is a longitudinally shaped member that extends in the axial direction of the photosensitive drum 2. The housing support member 55 is formed in a U-shape as shown in Figure 10. The housing support member 55 has a left side wall 55L, which is a first side wall, a right side wall 55R, which is a second side wall opposite the left side wall 55L, and a bottom surface 55D that faces the flat surface 54U of the housing 54 between the left side wall 55L and the right side wall 55R. The bottom surface 55D of the housing support member 55 is provided with a plurality of openings 55a in the longitudinal direction, which is the axial direction of the photosensitive drum 2.

[0072] The opening 55a of the housing support member 55 is located opposite the mounting surface (the front surface of the substrate 50) on which the LEDs 51 are mounted (the back surface of the substrate 50). The opening 55a is located between the left wall 55L and the right wall 55R in the short direction perpendicular to the longitudinal direction.

[0073] The first side wall, the left side wall 55L, is provided between the housing 54 that holds the substrate 50 and the developing unit 24, which is a developing means, on one side in the shorter direction perpendicular to the axial direction of the photosensitive drum 2, as shown in Figure 22. The left side wall 55L is provided across the axial direction of the photosensitive drum 2 so as to separate the housing 54 and the developing unit 24, as shown in Figure 11.

[0074] The second side wall, the right side wall 55R, is provided on the other side in the shorter direction, between the housing 54 and the adjacent drum unit 23, which is adjacent to the housing 54, as shown in Figure 22. The right side wall 55R, like the left side wall, is provided along the axial direction of the photosensitive drum 2 so as to separate the housing 54 and the drum unit 23.

[0075] By integrally providing this housing support member 55 with the housing 54, the airflow sent from the duct unit 60 (described later) is blown onto the back surface of the substrate 50 through the opening 55a between the left wall 55L and the right wall 55R of the housing support member 55. Moreover, the airflow blown onto the back surface of the substrate 50 is blown in a direction perpendicular to the back surface of the substrate 50.

[0076] In this manner, the airflow blown onto the back surface of the substrate 50 from the opening 55a of the housing support member 55 is separated from the developing unit 24 adjacent to the exposure head 4 by the left wall 55L, and from the drum unit 23 by the right wall 55R. Therefore, the airflow that cools the exposure head 4, which is introduced onto the back surface of the substrate 50, does not leak to the developing unit 24 adjacent to the exposure head 4, and the scattering of toner from the developing unit 24 inside the image forming apparatus can be suppressed.

[0077] (Engaging claw) As shown in Figures 11 and 12, the exposure head 4 has first engaging parts, which are engaging claws 55b and 55c. The engaging claws 55b and 55c are provided on the housing support member 55 of the exposure head 4 and engage with the lifting duct 69 by snap-fit.

[0078] In the housing support member 55 of the exposure head 4, the bottom surface portion 55D between the opening 55a at one end in the longitudinal direction (front side) and the adjacent opening 55a is defined as the first bottom surface portion 55D1. Similarly, the bottom surface portion 55D between the opening 55a at the other end in the longitudinal direction (rear side) and the adjacent opening 55a is defined as the second bottom surface portion 55D2. The lower surface of the first bottom surface portion 55D1 is provided with an engaging claw 55b that engages with the lifting duct 69. The lower surface of the second bottom surface portion 55D2 is provided with an engaging claw 55c that engages with the lifting duct 69. The first bottom surface portion 55D1 and the second bottom surface portion 55D2, i.e., the bottom surface portions 55D, are opposing portions that face the upper surface portion 69U of the lifting duct 69.

[0079] The first engaging parts, the engaging claws 55b and 55c, are formed on the bottom surface 55D so as to protrude toward the lifting duct 69 in the direction of movement of the lifting duct 69, which will be described later, and are further formed to extend in the axial direction of the photosensitive drum 2, which is perpendicular to the direction of protrusion.

[0080] Specifically, the engaging claws 55b and 55c of the exposure head 4 are formed to protrude toward the lifting duct 69 and are further formed to extend in the axial direction of the photosensitive drum 2 perpendicular to the protruding direction, thus having a roughly L-shape. As will be described later, by sliding the exposure head 4, the tips of the roughly L-shaped claws 55b and 55c engage with the edges of the engaging holes 69b and 69c by snap-fit, and become one with the lifting duct 69.

[0081] (shielding wall) The housing support member 55 is equipped with a shielding wall 76. The shielding wall 76 will be explained with reference to Figure 19. Figure 19 is a perspective view from below of the exposure head 4, in which the housing 54 and the housing support member 55 are integrally formed.

[0082] For reasons to be described later, the housing support member 55 includes a shielding wall 76 that separates the connector area on the back of the circuit board 50 where the FFC connector 57 is located from the duct area where the opening 55a is located behind the connector area in the front-rear direction.

[0083] The connector 57 is positioned off-center to one end of the substrate 50 in the longitudinal direction. On the other hand, multiple openings 55a are formed on the other end of the substrate 50 in the longitudinal direction, relative to the connector 57. The shielding wall 76 is provided to separate the openings 55a from the connector 57.

[0084] The shielding wall 76 is provided on the bottom surface 55D of the housing support member 55. The shielding wall 76 is provided on the side of the bottom surface 55D facing the back surface of the substrate 50, so as to protrude in the direction of the back surface of the substrate 50. The shielding wall 76 is provided between the left wall 55L and the right wall 55R of the housing support member 55. Between the left wall 55L and the right wall 55R, the shielding wall 76 separates the duct area on the back surface of the substrate 50 held by the housing 54 from the connector area of ​​the FFC connector 57 mounted on the substrate 50. Here, the duct area on the back surface of the substrate 50 is the area facing the opening 55a provided on the bottom surface 55D of the housing support member 55, and is the area (range La shown in Figure 20) that communicates with the opening 61 of the duct unit 60 via a closed space formed by the lifting duct 69 and the cartridge tray 30, which will be described later. The connector area mounted on the back surface of the substrate 50 is the area on the back surface of the substrate where the FFC connector 57 is mounted, and is the area outside the duct area (range La) in the axial direction of the photosensitive drum 2, and is the area in front of the duct area in the front-to-back direction, and is the area shown as range Lc in Figure 20.

[0085] As shown in Figure 20, a shielding wall 76 is provided on the housing support member 55 that separates the area La (duct area) and the area Lc (connector area). This prevents air blown onto the back surface of the substrate 50 held by the housing 54 from leaking out of the opening 55a of the housing support member 55 towards the FFC connector 57, thereby suppressing a decrease in the cooling capacity for the substrate 50.

[0086] Furthermore, the shielding wall 76 separates the duct area from the connector area so that the connector area is outside the duct area and on one end side in the axial direction of the photosensitive drum 2. In addition, the shielding wall 76 separates the duct area from the connector area so that the connector area is on the front side in the front-to-back direction of the image forming apparatus 100. For this reason, the FFC connector 57 is positioned as far forward as possible in order to make the range La as long as possible. This prevents the air blown onto the back surface of the substrate 50 from being blocked by the FFC 58 connected to the FFC connector 57 and flowing in an unintended direction. In other words, the air blown from the duct unit 60, which will be described later, toward the exposure head 4 is blown onto the back surface of the substrate 50 without being blocked by the FFC 58 connected to the FFC connector 57. The air blown onto the back surface of the substrate 50 tries to flow along the longitudinal direction of the substrate 50 in the space between the left wall 55L and the right wall 55R of the housing support member 55. At this time, the airflow toward the connector area is blocked by the shielding wall 76, and the airflow blown onto the back surface of the substrate 50 flows through the duct area from one side (front) to the other side (rear). Therefore, the airflow blown from the duct unit 60 (described later) onto the back surface of the substrate 50 can be directed in the intended direction, and toner scattering within the image forming apparatus due to airflow flowing in unintended directions can be suppressed.

[0087] In Figure 26, ranges Li and Lo are the respective ranges obtained by dividing the duct region La into two equal parts: the intake side and the exhaust side. Range Li is the intake side range when range La is divided into two equal parts. Range Lo is the exhaust side range when range La is divided into two equal parts. Range Ls is the range within the intake side range Li of the duct region La where the cross-sectional area of ​​the airflow inside the duct is locally narrowed.

[0088] As described above, the exposure head 4 is configured as an integrated head unit by a substrate having LEDs, a lens array consisting of multiple lenses, a housing 54, and a housing support member 55.

[0089] (Lifting duct) The image forming apparatus 100 is equipped with a lifting duct 69. The lifting duct 69 will be described with reference to Figures 22, 23, 27, and 28. Figures 22 and 23 are cross-sectional views taken along the XX arrow in Figure 20. Figures 27 and 28 are perspective views of the exposure head 4, the lifting duct 69, and the rotating arm 65.

[0090] The lifting duct 69 is an exposure support member that detachably supports the exposure head 4, and together with the cartridge tray 30 described later, it is provided on the main body of the image forming apparatus 100.

[0091] The lifting duct 69 is provided between the developing support member 301, which supports the developing unit 24 of the cartridge tray 30 (described later), and the drum support member 302, which supports the drum unit 23. The lifting duct 69 is provided between the developing support member 301 and the drum support member 302 of the cartridge tray 30 so as to be movable between an exposure position (see Figures 22 and 24) where the photosensitive drum 2 is exposed, and a retracted position (see Figures 25 and 23) where it is retracted from the exposure position. The lifting duct 69 is supported from below at both ends in the longitudinal direction by a rotating arm 65 (described later). The lifting duct 69 is moved by the rotating arm 65 in a direction perpendicular to the axial direction of the photosensitive drum 2 (first direction, direction of movement), together with the exposure head 4. The lifting duct 69 is moved to the exposure position or the retracted position by the rotation of the rotating arm 65.

[0092] The lifting duct 69 has a longitudinal shape that extends in the front-to-back direction (axis direction of the photosensitive drum), similar to the exposure head 4, so as to support the entire exposure head 4, and its central part has openings at the top and bottom. The lifting duct 69 has one opening 69a that communicates with the opening 55a of the exposure head 4, and the other opening 64 that communicates with the opening 61 of the duct unit 60, forming a duct. The lifting duct 69 supports the exposure head 4 and at the same time forms part of a duct that cools the exposure head 4.

[0093] The lifting duct 69 has an upper surface portion 69U that faces the bottom surface portion 55D of the housing support member 55. Figure 26 (See reference). The upper surface portion 69U of the lifting duct 69 is provided with a plurality of openings 69a in the longitudinal direction, which is the axial direction of the photosensitive drum 2. The lifting duct 69 has a left duct wall 69L, a right duct wall 69R opposite to the left duct wall 69L, a front duct wall 69F, and a rear duct wall 69B opposite to the front duct wall 69F. The left duct wall 69L, the right duct wall 69R, the front duct wall 69F, and the rear duct wall 69B are integrally provided on the upper surface portion 69U so as to surround the periphery of the upper surface portion 69U, that is, so as to surround the openings 69a provided on the upper surface portion 69U. As a result, the lifting duct 69 is formed with an integrated upper surface 69U, left duct wall 69L, right duct wall 69R, front duct wall 69F, and rear duct wall 69B, and has openings at the top and bottom. The lifting duct 69 then forms a duct (closed space) that allows airflow from the duct unit 60 (described later) to flow to the exposure head 4 through the gaps between the duct walls and the opening 69a in the upper surface 69U.

[0094] The multiple openings 69a are each provided in positions opposite to the multiple openings 55a provided in the bottom surface portion 55D of the housing support member 55. In other words, the openings 69a of the lifting duct 69 are provided in positions opposite to the back surface of the substrate 50, similar to the openings 55a of the housing support member 55. In other words, the lifting duct 69 has an opening 69a that communicates with the opening 55a of the exposure head 4.

[0095] The first duct wall, the left duct wall 69L, is located on the left side, which is one side in the shorter direction perpendicular to the axial direction of the photosensitive drum 2, via an opening 69a. That is, the left duct wall 69L is located opposite the developing unit 24, which is the developing means, and extends from the front duct wall 69F to the rear duct wall 69B along the axial direction of the photosensitive drum 2.

[0096] The left wall 69L of the duct has a first inclined surface 69L1 that, in the direction of movement from the exposure position to the retraction position, is inclined away from the right wall 69R of the duct from the upstream side to the downstream side. The first inclined surface 69L1 is similarly inclined from the front wall 69F of the duct to the rear wall 69B of the duct. The first inclined surface 69L1 is provided at a position opposite the developing support member 301 of the left wall 69L of the duct and forms a predetermined angle θ2 with respect to the direction of movement (direction of arrow G shown in Figure 22).

[0097] The second duct wall, the right duct wall 69R, is located on the right side, which is the other side in the shorter direction, through an opening 69a. That is, the right duct wall 69R is located opposite the drum unit 23, which is adjacent to the lifting duct 69, and is provided along the axial direction of the photosensitive drum 2, extending from the front duct wall 69F to the rear duct wall 69B.

[0098] The right wall 69R of the duct has a second inclined surface 69R1 that, in the direction of movement from the exposure position to the retraction position, is inclined away from the left wall 69L of the duct from the upstream side to the downstream side. The second inclined surface 69R1 is similarly inclined from the front wall 69F of the duct to the rear wall 69B of the duct. The second inclined surface 69R1 is provided at a position opposite the drum support member 302 of the right wall 69R of the duct and forms a predetermined angle θ1 with respect to the direction of movement (direction of arrow G shown in Figure 22).

[0099] The third duct wall, the front duct wall 69F, is located outside the multiple openings 69a provided in the upper surface portion 69U in the axial direction of the photosensitive drum.

[0100] The fourth duct wall, the rear duct wall 69B, is located outside the multiple openings 69a provided on the upper surface 69U in the axial direction of the photosensitive drum.

[0101] Multiple openings 69a provided in the upper surface portion 69U of the lifting duct 69 are located between the left wall 69L and the right wall 69R of the duct, and between the front wall 69F and the rear wall 69B of the duct.

[0102] In other words, the lifting duct 69 is formed by these duct walls into a hollow shape with no openings in the position facing the developing unit 24 and the drum unit 23, but with openings at the top and bottom.

[0103] Therefore, the lifting duct 69 directs the airflow from the duct unit 60 (described later) to the back surface of the substrate 50 of the exposure head 4 through the opening 64 (described later) and the opening 69a between the left wall 69L and the right wall 69R of the duct. As a result, the lifting duct 69 can direct the airflow from the duct unit 60 to the back surface of the substrate 50 of the exposure head 4 without leaking it to the adjacent developing unit 24 or drum unit 23, thereby reducing toner scattering inside the device.

[0104] Furthermore, the front wall 69F and rear wall 69B of the duct extend downward in the direction of movement compared to the left wall 69L and right wall 69R of the duct. In other words, the front wall 69F and rear wall 69B of the duct are ribs that protrude toward the duct unit 60, which will be described later, on both longitudinal sides of the opening 69a that communicates with the exposure head 4.

[0105] The lifting duct 69 integrally supports the exposure head 4 and, by communicating with the duct unit 60 described later, forms a duct (part of the second cooling duct) that allows the airflow from the duct unit 60 to flow to the exposure head 4 through the opening 69a. The duct walls 69F and 69B, which act as ribs, form part of the duct at the exposure position.

[0106] The front wall 69F of the duct and the rear wall 69B of the duct, together with the cartridge tray 30 described later, form an opening 64 (see Figure 21) that communicates with the opening 61 (see Figure 35) of the duct unit 60 described later.

[0107] Furthermore, the lifting duct 69 has a first engaging portion 69d and a second engaging portion 69e at both ends in the longitudinal direction, which engage with the rotating arm 65. The first engaging portion 69d is provided on the outside of the duct front wall 69F at one end in the longitudinal direction. The first engaging portion 69d is also provided on the outside of the area where the FFC connector 57 is provided, located on the outside of the duct front wall 69F at one end in the longitudinal direction. The second engaging portion 69e is provided on the outside of the duct rear wall 69B at the other end in the longitudinal direction.

[0108] Therefore, the region where the first engaging portion 69d is provided (range Lm in Figure 20) and the region where the second engaging portion 69e is provided (range Lm in Figure 20) are located outside the duct region (range La in Figure 20) where the opening 69a is surrounded by the duct wall. In other words, the duct region (range La in Figure 20) where the opening 69a is surrounded by the duct wall is located between the region where the first engaging portion 69d is provided (range Lm in Figure 20) and the region where the second engaging portion 69e is provided (range Lm in Figure 20).

[0109] The area where the FFC connector 57 is provided (area Lc in Figure 20) is located outside the duct area (area La in Figure 20) which forms a duct with the opening 69a surrounded by the duct wall, and is situated between the duct area and the area where the first engaging portion 69d is provided (area Lm in Figure 20).

[0110] Furthermore, the duct-forming area La includes most of the substrate 50 on which the LED 51 is mounted, and by blowing airflow into this area La, the exposure head 4 can be sufficiently cooled. Area Lc is where the FFC connector 57 for the signal line that transmits the drive signal to the substrate 50 on which the LED 51 is mounted is mounted. Although there is no opening to form a duct in area Lc, as described above, it is configured so that sufficient cooling can be achieved in area La.

[0111] As a result, air taken in from outside the apparatus by the duct unit 60 (described later) is blown onto the back surface of the substrate 50 through the opening 55a of the exposure head 4 via the lifting duct 69 (see Figure 37). The airflow blown onto the back surface of the substrate 50 through the opening 55a of the exposure head 4 is then exhausted to the outside of the apparatus by the duct unit 60 via the lifting duct 69 (see Figure 39).

[0112] (Engagement hole) As shown in Figure 26, the lifting duct 69 has engagement holes 69b and 69c, which are second engagement parts. The second engagement parts, engagement holes 69b and 69c, engage with the first engagement parts, engagement claws 55b and 55c, of the exposure head 4 by snap-fit.

[0113] In the lifting duct 69, the upper surface portion 69U between the opening 69a at one end in the longitudinal direction (front side) and the adjacent opening 69a is defined as the first upper surface portion 69U1. Similarly, the upper surface portion 69U between the opening 69a at the other end in the longitudinal direction (rear side) and the adjacent opening 69a is defined as the second upper surface portion 69U2. The first upper surface portion 69U1 is provided with an engagement hole 69b that engages with the engagement claw 55b of the exposure head 4. The second upper surface portion 69U2 is provided with an engagement hole 69c that engages with the engagement claw 55c of the exposure head 4. The first upper surface portion 69U1 and the second upper surface portion 69U2, i.e., the upper surface portions 69U, face the bottom surface portion 55D of the exposure head 4 (housing support member 55) and are support portions that detachably support the exposure head 4.

[0114] The second engagement portion, the engagement holes 69b and 69c, is formed on the upper surface portion 69U facing the exposure head 4, at positions corresponding to the engagement claws 55b and 55c.

[0115] As a result, the exposure head 4 is configured to be detachable from the image forming apparatus 100. The exposure head 4 is moved (downward D as shown in Figure 49) so that the engaging claws 55b and 55c of the exposure head 4 are dropped into the engaging holes 69b and 69c of the lifting duct 69, respectively, and the bottom surface 55D of the exposure head 4 comes into contact with the top surface 69U of the lifting duct 69. In other words, the exposure head 4 is moved in a direction perpendicular to the axial direction of the lifting duct 69 so that the engaging claws 55b and 55c engage with the engaging holes 69b and 69c in a protruding direction.

[0116] Subsequently, by moving the exposure head 4 along the upper surface portion 69U of the lifting duct 69 (rearward direction B as shown in Figure 52), the engaging claws 55b and 55c of the exposure head 4 are snap-fitted into the engaging holes 69b and 69c of the lifting duct 69, respectively.

[0117] Specifically, the exposure head 4 is moved in the axial direction relative to the lifting duct 69, and the engaging claws 55b and 55c are engaged with the engaging holes 69b and 69c in an extending direction perpendicular to the protruding direction. In this way, the exposure head 4 is connected to the lifting duct 69 in the image forming apparatus 100, and the exposure head 4 becomes an integral part of the lifting duct 69. The procedure for removing the exposure head 4 from the lifting duct 69 is the reverse of the procedure described above. The configuration for replacing and attaching / detaching the exposure head will be explained in detail later.

[0118] (Cartridge tray) The image forming apparatus 100 also includes a cartridge tray 30. The cartridge tray 30 will be described with reference to Figures 8, 9, 20, 22, and 21. Figures 8, 9, and 20 are perspective views of the cartridge tray 30. Figure 21 is a view of the cartridge tray 30 from below.

[0119] The cartridge tray 30 is a support member that supports the drum unit 23 and the developing unit 24 mentioned above, and guides and supports the attachment and detachment operation along the axial direction of the photosensitive drum 2. The cartridge tray 30 pivots the pivot shaft 102a of the inner door 102 so that the inner door 102 can rotate freely within a predetermined range.

[0120] A cartridge tray 30 is provided for each image forming unit. Each cartridge tray 30 includes a developing support member 301 that guides and supports the attachment and detachment of the developing unit 24 along the axial direction of the photosensitive drum 2, and a drum support member 302 that guides and supports the attachment and detachment of the drum unit 23 along the axial direction of the photosensitive drum 2. The developing support member 301 and the drum support member 302 are integrally formed in the cartridge tray 30. Note that the configuration of providing a cartridge tray 30 for each image forming unit is not limited to this.

[0121] The lifting duct 69 is movably positioned between the developing support member 301 and the drum support member 302 of the cartridge tray 30. Between the developing support member 301 and the drum support member 302, the first engaging portion 69d and the second engaging portion 69e at both ends in the longitudinal direction of the lifting duct 69 are supported from below by a rotating arm 65. The rotating arm 65 is rotatably mounted on the developing support member 301 of the cartridge tray 30, as will be described later. The exposure head 4 is detachably mounted on the lifting duct 69, which is movably positioned on the cartridge tray 30. In other words, the cartridge tray 30 is a support member that supports the exposure head 4 and guides and supports the attachment and detachment operation along the axial direction of the photosensitive drum 2.

[0122] (Developing support member) The developing support member 301 is a developing support member that guides and supports the attachment and detachment operation of the developing unit 24 along the axial direction of the photosensitive drum, and is a longitudinally shaped member that extends in the axial direction of the photosensitive drum 2. The developing support member 301 has a first developing guide portion 301a, a second developing guide portion 301b facing the first developing guide portion 301a, and a developing bottom portion 301c provided between the first developing guide portion 301a and the second developing guide portion 301b. The developing support member 301 is integrally formed with the first developing guide portion 301a, the second developing guide portion 301b, and the developing bottom portion 301c.

[0123] The developing bottom portion 301c faces the bottom portion 24D of the frame of the developing unit 24 with a space between them, and is provided along the longitudinal direction, which is the axial direction of the photosensitive drum 2. The first developing guide portion 301a is provided on one end of the developing bottom portion 301c in the short direction perpendicular to the longitudinal direction, and is provided between the lifting duct 69 and the developing unit 24 so as to separate the lifting duct 69 from the developing unit 24. The second developing guide portion 301b is provided on the other end of the developing bottom portion 301c in the short direction, and is provided so as to face the first developing guide portion 301a. The first developing guide portion 301a and the second developing guide portion 301b each abut the frame of the developing unit 24 and guide the developing unit 24, which is inserted and removed in the longitudinal direction, along the longitudinal direction.

[0124] The first developing guide section 301a has a facing section 301d that faces the first inclined surface 69L1 of the lifting duct 69. The facing section 301d has a first tray inclined surface that is inclined in the same way as the first inclined surface 69L1 of the lifting duct 69.

[0125] The first development guide section 301a has a partition wall section 301e downstream of the opposing section 301d in the direction of movement from the retracted position of the lifting duct 69 toward the exposure position. The partition wall section 301e is provided between the exposure head 4 and the development unit 24 so as to separate the exposure head 4 and the development unit 24, which are located at the exposure position shown in Figure 22. The partition wall section 301e is the end (upper end) on the development sleeve side of the first development guide section 301a.

[0126] As shown in Figures 2, 8, and 22, the developing support member 301 (cartridge tray 30) is positioned directly below the developing unit 24. The developing support member 301 (cartridge tray 30) forms a closed duct space between its upper surface and the bottom surface of the developing unit 24, and in addition to guiding the attachment and detachment of the developing unit, it also functions as an intermediate path for the developing cooling airflow, which will be described later.

[0127] As will be described later, the duct (closed space) formed by the upper surface of the cartridge tray 30 (developing support member 301) and the upper surface of the developing unit 24 has an opening at one end (front side) in the longitudinal direction that communicates with an opening 41a in the front duct 41, which takes in air from outside the device, via an opening 102c in the inner door 102. The other end (rear side) of the duct also has an opening 42a in the rear duct 42, which exhausts air to the outside of the device. The duct between the developing unit 24 and the developing support member 301 forms a single closed space that communicates with the front duct 41 and the rear duct 42 (see Figure 34).

[0128] (Drum support member) The drum support member 302 is a photoreceptor support member that guides and supports the attachment and detachment operation of the drum unit 23 along the axial direction of the photoreceptor drum, and is a longitudinally shaped member that extends in the axial direction of the photoreceptor drum 2. The drum support member 302 has a first drum guide portion 302a, a second drum guide portion 302b facing the first drum guide portion 302a, and a drum bottom portion 302c provided between the first drum guide portion 302a and the second drum guide portion 302b. The drum support member 302 is integrally formed with the first drum guide portion 302a, the second drum guide portion 302b, and the drum bottom portion 302c.

[0129] The drum bottom portion 302c is located opposite the bottom portion 23D of the frame of the drum unit 23 and extends along the longitudinal direction, which is the axial direction of the photosensitive drum 2. The first drum guide portion 302a is located on one end of the drum bottom portion 302c in the short direction perpendicular to the longitudinal direction and is located between the lifting duct 69 and the drum unit 23 so as to separate the lifting duct 69 from the drum unit 23. The second drum guide portion 302b is located on the other end of the drum bottom portion 302c in the short direction and is located opposite the first drum guide portion 302a. The first drum guide portion 302a and the second drum guide portion 302b each contact the frame of the drum unit 23 and guide the drum unit 23, which is inserted and removed in the longitudinal direction, along the longitudinal direction.

[0130] The first drum guide portion 302a has a facing portion 302d that faces the second inclined surface 69R1 of the lifting duct 69. The facing portion 302d has a second tray inclined surface that is inclined in the same way as the second inclined surface 69R1 of the lifting duct 69.

[0131] (Relationship between cartridge tray and lifting duct) Here, we will explain the relationship between the cartridge tray 30 and the lifting duct 69.

[0132] The lifting duct 69 is movably positioned between the first development guide section 301a and the first drum guide section 302a in the cartridge tray 30, and is moved between the exposure position shown in Figure 24 and the retracted position shown in Figure 25 by the rotation of the rotating arm 65, which will be described later. In other words, the first development guide section 301a and the first drum guide section 302a of the cartridge tray 30 function as guide members that guide the lifting duct 69 in its direction of movement.

[0133] Furthermore, the lifting duct 69 is integrated with the exposure head 4 by the detachable mounting of the exposure head 4, so that the opening 55a of the exposure head 4 and the opening 69a of the lifting duct 69 are in communication. The lifting duct 69 is separated from the development unit 24 by the first development guide portion 301a of the cartridge tray 30, and separated from the drum unit 23 by the first drum guide portion 302a of the cartridge tray 30. In addition, at the exposure position shown in Figure 22, the gap between the lifting duct 69 and the first development guide portion 301a is sealed by a seal 72, which is a sealing member described later. Similarly, at the exposure position shown in Figure 22, the gap between the lifting duct 69 and the first drum guide portion 302a is sealed by a seal 71, which is a sealing member described later.

[0134] In this way, the cartridge tray 30 and the lifting duct 69, which is positioned between the first development guide section 301a and the first drum guide section 302a of the cartridge tray 30, form a duct that is a closed space communicating with the opening 55a of the exposure head 4.

[0135] (Relationship between cartridge tray, lifting duct and duct unit) Furthermore, the cartridge tray 30 and the lifting duct 69 have an opening 64 on the side facing the duct unit 60 (described later) that communicates with the opening 61 of the duct unit 60.

[0136] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 will be explained using Figures 22 and 21.

[0137] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 is formed by the developing support member 301, the drum support member 302, and the lifting duct 69 between the developing support member 301 and the drum support member 302, as shown in Figure 21. More specifically, the opening 64 is formed by the developing guide portion 301a of the developing support member 301, the drum guide portion 302a of the drum support member 302, and the front wall 69F and rear wall 69B of the lifting duct 69 between the developing guide portion 301a and the drum guide portion 302a.

[0138] In this way, the cartridge tray 30 and the lifting duct 69 have openings 64 on the side facing the duct unit 60 (described later) that communicate with the opening 61 of the duct unit 60. When the duct unit 60 (described later) is mounted on the image forming apparatus 100, the opening 61 of the duct unit 60 is pressed from below against the opening 64 formed by the cartridge tray 30 and the lifting duct 69. As a result, the opening 64 formed by the cartridge tray 30 and the lifting duct 69 communicates with the opening 61 of the duct unit.

[0139] Furthermore, the opening 64 formed by the cartridge tray 30 and the lifting duct 69, and the opening 61 of the duct unit are sealed by a sealing member 207, which will be described later.

[0140] (Relationship between the ribs and duct unit of the lifting duct) Furthermore, the ribs of the lifting duct 69, namely the duct front wall 69F and the duct rear wall 69B, will be explained in detail.

[0141] As will be described later, of the sealing members 207 provided in the opening 61 of the duct unit 60, the sealing member 207 provided in the longitudinal direction is sandwiched between the duct unit 60 and the first developing guide portion 301a and the first drum guide portion 302a of the cartridge tray 30 facing it, as shown in Figure 37, sealing the space between them. The first developing guide portion 301a and the first drum guide portion 302a of the cartridge tray 30 are located on both sides in the left-right direction of the lifting duct 69 (see Figure 22).

[0142] Therefore, sealing of the left and right ends of the opening of the lifting duct 69, i.e., the boundary with the longitudinal duct unit 60 in the range La shown in Figure 20, is achieved by sealing the space between the duct unit 60 and the cartridge tray 30 with the sealing member 207. As a result, a sealed state is always maintained without being affected by the movement of the lifting duct 69.

[0143] On the other hand, a different sealing configuration is required at the front and rear ends of the opening of the lifting duct 69, that is, at the boundary between range La and range Lc, and at the boundary between range La and range Lm, as shown in Figure 20. This is because the boundary between the front and rear ends of the opening of the lifting duct 69 and the duct unit 60 cannot be sealed in the same way as the boundary between the cartridge tray 30 and the duct unit 60.

[0144] In this embodiment, the front and rear ends of the duct unit 60 are sealed between the opening 61 (see Figure 35) and the duct front wall 69F and the duct rear wall 69B shown in Figure 28.

[0145] Figures 29 and 30 show cross-sections of the exposure head 4, the lifting duct 69, and the duct unit 60. The positions of the cross-sections shown in Figures 29 and 30 correspond to the positions indicated by the EE arrow in Figure 37, and the cartridge tray 30 is not shown. Figure 29 is a cross-sectional view showing the arrangement of the lifting duct 69 when it has been moved to the exposure position. Figure 30 is a cross-sectional view showing the arrangement of the lifting duct 69 when it has been moved to the retracted position.

[0146] The front wall 69F and rear wall 69B of the lifting duct 69 are positioned outside the duct region (area La in Figure 20) where the opening 69a of the lifting duct 69 is provided, in the axial direction of the photosensitive drum 2. The front wall 69F and rear wall 69B have a length that protrudes toward the duct unit 60, which will be described later, in the direction of movement of the lifting duct 69, and overlaps with the side surface of the duct unit 60 (see Figures 29 and 30). The length of the front wall 69F and rear wall 69B is such that, when the exposure head 4 is in the exposure position, the front wall 69F and rear wall 69B overlap with the side surface of the sealing member 207 provided in the opening 61 of the duct unit 60. The front wall 69F and rear wall 69B of the duct, both in the exposure position shown in Figure 29 and the retracted position shown in Figure 30, have sides on the opening 69a side that contact the longitudinally outer side of the sealing member 207 provided in the opening 61 of the duct unit 60, which will be described later. In other words, the front wall 69F and rear wall 69B of the duct have the length such that, in the exposure position shown in Figure 22, the sides on the opening 69a side contact the longitudinally outer side of the sealing member 207 provided in the opening 61 of the duct unit 60, which will be described later.

[0147] In the exposure position shown in Figure 29, the lifting duct 69 has its front wall 69F and rear wall 69B forming walls at the front and rear ends of the range La. Furthermore, sealing between the front wall 69F and rear wall 69B of the duct and the duct unit 60 is achieved by the contact between the side surface of the sealing member 207 on the upper surface of the duct unit 60 and the side surfaces of the front wall 69F and rear wall 69B of the duct.

[0148] In the retracted position shown in Figure 30, the lifting duct 69 is retracted so that the sides of the front wall 69F and the rear wall 69B of the duct overlap the outside of the sides of the duct unit 60, and does not interfere with the duct unit 60.

[0149] Furthermore, as shown in Figure 28, the left wall 69L and the right wall 69R of the lifting duct 69 are shorter in length in the direction of movement (UD axis direction) than the front wall 69F and the rear wall 69B of the duct. The left wall 69L and the right wall 69R of the lifting duct 69 are of a length such that they do not protrude below the cartridge tray 30 when the exposure head 4 is in the retracted position (see Figure 23).

[0150] In other words, the height of the left wall 69L and the right wall 69R of the lifting duct 69 in the range La shown in Figure 20 is lower than the front wall 69F and the rear wall 69B of the duct at both ends that are outside the range La. Figure 28 shows a perspective view of the exposure head 4 and the lifting duct 69 engaged and integrated. As shown in Figure 28, in the front-rear direction, the left wall 69L (and the right wall 69R) of the duct in the range La is configured to be lower, with the front wall 69F and the rear wall 69B of the duct as the boundary.

[0151] This is to prevent the lower ends of the left wall 69L and right wall 69R of the lifting duct 69 from protruding from the cartridge tray 30 and entering the interior of the duct unit 60, even when the lifting duct 69 is retracted from the photosensitive drum 2.

[0152] Even if the left wall 69L and right wall 69R of the lifting duct 69 within range La are not lowered and are configured to penetrate the interior of the duct unit 60, sealing is still possible. In that case, the third opening 201 and fourth opening 202 on the upper surface of the duct unit 60 must be large enough for the retracted lifting duct 69 to enter, and furthermore, space must be required inside the duct unit 60 to accommodate the retracted lifting duct 69. This imposes constraints on the shape of the duct unit 60. In addition, it also imposes constraints on the assembly order of the duct unit 60. For this reason, it is desirable to keep the left wall 69L and right wall 69R of the lifting duct 69 within range La lower than the front and rear walls of the duct so that they do not protrude below the cartridge tray 30 when the exposure head 4 is in the retracted position.

[0153] With this configuration, the lower ends of the left duct wall 69L and the right duct wall 69R do not enter the interior of the duct unit 60 when the exposure head 4 is moved to the retracted position, and thus do not obstruct its movement.

[0154] With this configuration, the lifting duct 69, which moves together with the exposure head 4, forms a duct that guides air from the duct unit 60 to the exposure head 4, and also provides sealing between the duct unit 60 and the duct, thereby reducing toner scattering inside the image forming apparatus.

[0155] In addition, the configuration shown in Figure 30 illustrates how the front wall 69F and rear wall 69B of the lifting duct 69 overlap the side surface that is outside the opening 61 of the duct unit 60 in the retracted position shown. However, the present invention is not limited to this. For example, the configuration may be such that only the front wall 69F and the rear wall 69B of the left wall 69L, right wall 69R, front wall 69F, and rear wall 69B of the duct penetrate inside the openings 201 and 202 of the duct unit 60.

[0156] (Development Stay) The cartridge tray 30 includes a developing stay 31 that slides along the axial direction of the photosensitive drum 2. The developing stay 31 will be described with reference to Figures 31 and 32. Figures 31 and 32 are side views of the developing stay 31 as seen from the right.

[0157] The developing stay 31, which is a sliding member, is movably mounted relative to the developing support member 301 of the cartridge tray 30. The developing stay 31 is movably mounted on the developing bottom surface portion 301c of the developing support member 301 in the axial direction of the photosensitive drum 2. The developing stay 31 has an elongated shape (longitudinal shape) extending in the axial direction of the photosensitive drum 2 and includes a developing pressure block 32, a developing pressure block 33, a developing stay link 34, an arm retraction member 68F, and an arm retraction member 68B.

[0158] The developing stay link 34 is fixed to the front end of the developing stay 31 and engages with the inner door 102 which is pivotally supported by the cartridge tray 30. The developing pressure block 32 is fixed to one longitudinal side (front side) of the developing stay 31, and the developing pressure block 33 is fixed to the other longitudinal side (rear side) of the developing stay 31. The developing pressure blocks 32 and 33 are positioned opposite the developing unit 24.

[0159] When the inner door 102 is open, the link engagement portion 102b that engages with the developing stay link 34 is located closer to the rear end (lower end when open) of the inner door 102 than to the pivot axis 102a. Therefore, as the inner door 102 rotates, the link engagement portion 102b of the inner door 102 moves in the rotational direction along the trajectory of a circle with a radius equal to the distance between the pivot axis 102a and the link engagement portion 102b. In other words, as shown in Figure 32, opening the inner door 102 causes the link engagement portion 102b to also rotate and move towards the rear of the device.

[0160] This causes the developing stay link 34, which engages with the link engagement portion 102b of the inner door 102, to slide in the direction of arrow B, which is towards the rear of the device, and the two developing pressure blocks 32 and 33, which are integrally formed through the developing stay 31, also slide in the direction of arrow B. As shown in Figure 32, this means that the two developing pressure blocks 32 and 33 are released from the position that holds the developing unit 24. When the developing pressure blocks 32 and 33 are released from their holding position, the developing unit 24 moves in the direction of arrow D, which is the direction that moves it away from the photosensitive drum 2 due to its own weight.

[0161] From the above explanation, it can be seen that the developing unit 24 retracts from the photosensitive drum 2 in conjunction with the opening of the inner door 102. When closing the inner door 102, the developing unit 24 is moved toward the photosensitive drum 2 and pressed down by following the reverse procedure of the opening operation.

[0162] In this manner, the developing stay 31 slides in the front-rear direction by a developing stay link 34 that engages with a link engagement portion 102b, in conjunction with the opening and closing operation of the inner door 102. The sliding movement of the developing stay 31 in the front-rear direction moves the developing unit 24 between a developing position (see Figure 22) where the developing sleeve 5 is close to the photosensitive drum 2 during development, and a separated position (see Figure 23) where the developing sleeve 5 is separated from the photosensitive drum 2 when not developing.

[0163] As shown in Figure 31, the developing stay 31 slides forward F in conjunction with the closing of the inner door 102. At this time, the developing unit 24 moves upward (arrow U) along the slopes of the developing pressure slabs 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves in a direction closer to the photosensitive drum 2 of the drum unit 23.

[0164] Furthermore, as shown in Figure 32, the developing stay 31 slides backward B in conjunction with the opening of the inner door 102. At this time, the developing unit 24 moves downward (arrow D) along the slope of the developing pressure slabs 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves away from the photosensitive drum 2 of the drum unit 23, and the developing sleeve 5 is separated from the photosensitive drum 2 compared to during development.

[0165] Furthermore, the developing stay 31 includes an arm retraction member 68F and an arm retraction member 68B for rotating the rotating arm 65, which will be described later. The arm retraction members 68F and 68B are integrally configured with the developing stay 31. The arm retraction member 68F is fixed to one side of the developing stay 31 in the longitudinal direction (front side of the device) and is provided on the side opposite to the developing pressure chamber 32. The arm retraction member 68B is fixed to the other side of the developing stay 31 in the longitudinal direction (rear side of the device) and is provided on the side opposite to the developing pressure chamber 33. The arm retraction members 68F and 68B move in the same direction as the developing stay 31 slides in the front-rear direction in conjunction with the opening and closing operation of the inner door 102, thereby rotating the rotating arm 65.

[0166] The developing stay 31 disengages from the rotating arm 65 by moving in one direction along the axis. This causes the rotating arm 65 to rotate in one direction, moving the exposure head 4 to the exposure position together with the lifting duct 69. On the other hand, the developing stay 31 engages with the rotating arm 65 by moving in the other direction along the axis. This causes the rotating arm 65 to rotate in the other direction, moving the exposure head 4 to the retracted position together with the lifting duct 69.

[0167] (Rotating arm) As shown in Figures 24 and 25, the rotating arm 65, which is a rotating member, is rotatably mounted on the developing support member 301 of the cartridge tray 30. One end of the rotating arm 65 in the left-right direction perpendicular to the axial direction of the photosensitive drum 2 is supported so as to be rotatable about an axis parallel to the axial direction. The other end of the rotating arm 65 in the left-right direction, which is an engaging boss 66, supports engaging portions 69d and 69e at both ends of the region outside the opening 69a of the lifting duct 69 in the axial direction.

[0168] Specifically, the rotating arm 65 rotates at one end in the left-right direction around a pivot axis 30a integrally provided on the cartridge tray 30. The pivot axis 30a is centered on an axis parallel to the direction of movement of the developing stay 31 and is integrally provided on the back surface of the developing bottom surface portion 301c of the developing support member 301, on the side opposite to the surface facing the developing unit 24. The direction of movement of the developing stay 31 can be described as either the axial direction of the rotation center of the photosensitive drum 2, or the longitudinal direction of the drum unit 23, developing unit 24, and exposure head 4. This is the condition that allows the rotating arm 65 to be positioned most compactly relative to the width dimension of the cartridge tray 30 shown in Figure 25, taking into account the operation of the arm retraction members 68F and 68B, which will be described later. Consequently, this also minimizes the impact on the arrangement and operation of the surrounding components of the rotating arm 65.

[0169] The rotating arm 65 has an engagement boss 66 at its tip, which is the other end in the left-right direction. The engagement boss 66 is provided on the end of the rotating arm 65 opposite to the pivot axis 30a. The rotating arm 65 supports both ends of the region outside the opening 55a in the longitudinal direction of the exposure head 4 from below. That is, the rotating arm 65 supports both ends of the lifting duct 69 that supports the exposure head 4 in the longitudinal direction in the region outside the duct region (region La in Figure 20) of the exposure head 4 (region Lm in Figure 20). Specifically, the rotating arm 65 supports the bottom surfaces of the first engagement portion 69d and the second engagement portion 69e at both ends of the lifting duct 69 in the longitudinal direction from below, respectively, by the engagement boss 66 provided at its tip.

[0170] The rotating arm 65 presses upward the bottom surfaces of the first engagement portion 69d and the second engagement portion 69e at both ends in the longitudinal direction of the lifting duct 69 by the force of the arm pressure spring 67, which is a biasing member. Here, a torsion coil spring is used as the arm pressure spring 67. In Figure 24, the exposure head 4 is positioned close to the photosensitive drum 2, and this is maintained by the rotating arm 65 pressing upward the bottom surfaces of the first engagement portion 69d and the second engagement portion 69e at both ends of the lifting duct 69. This pressure is ensured by a predetermined spring pressure from the arm pressure spring 67.

[0171] In this manner, the rotating arm 65 does not directly press against the exposure head 4, but rather presses against the lifting duct 69 that supports the exposure head 4.

[0172] The rotating arm 65, together with the arm pressure spring 67 and the pivot shaft 102a provided on the cartridge tray 30, constitutes a moving mechanism (retraction mechanism) for raising and lowering the lifting duct 69. In other words, the moving mechanism for moving (raising and lowering) the lifting duct 69 comprises the pivot shaft 102a, the rotating arm 65 which is a rotating member that rotates around the pivot shaft 102a, and the arm pressure spring 67 which is a biasing member that biases the rotating arm 65.

[0173] The rotating arm 65 rotates around the pivot axis 30a in response to the sliding movement of the developing stay 31, moving the exposure head 4 to the exposure position (see Figure 24) or the retracted position (see Figure 25). Specifically, the rotating arm 65, in conjunction with the opening and closing of the inner door 102, moves the exposure head 4 to the exposure position to expose the photosensitive drum 2 by rotating in one direction, and moves the exposure head 4 to the retracted position, which is the position away from the exposure position, by rotating in the other direction.

[0174] Specifically, as shown in Figure 32, the developing stay 31 slides in the rearward direction B in conjunction with the opening of the inner door 102. At this time, the arm retraction members 68F and 68B, which are moved in the rearward direction B, engage with the rotating arm 65. As a result, the rotating arm 65 rotates and is pushed downward against the force of the arm pressure spring 67 (see Figure 25). This rotation of the rotating arm 65 causes the engagement boss 66 provided at the tip of the rotating arm 65 to push down the engagement ribs 69d1 and 69e1 provided at the lower ends of the engagement portions 69d and 69e of the lifting duct 69, thereby retracting the exposure head 4, which is integrated with the lifting duct 69, from the photosensitive drum 2. In other words, the exposure head 4 is moved from the exposure position to the retracted position.

[0175] The retraction of the rotating arm 65 is performed by inserting wedge-shaped arm retraction members 68F and 68B between the upper surface of the rotating arm 65 and the lower surface of the cartridge tray 30 at a position close to the pivot shaft 30a.

[0176] Furthermore, as shown in Figure 31, the developing stay 31 slides forward in direction F in conjunction with the closing of the inner door 102. At this time, the arm retraction members 68F and 68B move forward in direction F, and the engagement between the arm retraction members 68F and 68B and the rotating arm 65 is released. As a result, the rotating arm 65 rotates and is pushed upward by the force of the arm pressure spring 67 (see Figure 24). This rotation of the rotating arm 65 causes the engagement boss 66 provided at the tip of the rotating arm 65 to push up the bottom surfaces of the engagement portions 69d and 69e of the lifting duct 69, thereby bringing the exposure head 4, which is integrated with the lifting duct 69, closer to the photosensitive drum 2. In other words, the exposure head 4 is moved from the retracted position to the exposure position.

[0177] Thus, one end of the rotating arm 65, in a direction perpendicular to the axial direction of the photosensitive drum 2, is supported by the rotating shaft 102a so as to be rotatable about an axis parallel to the axial direction. The other end of the rotating arm 65, the engaging boss 66, supports the engaging portions 69d and 69e, which are the ends of the region outside the opening 69a of the lifting duct 69 in the axial direction. As described above, the movement mechanism of the exposure head 4 is established even within the range Lm shown in Figure 20.

[0178] Furthermore, the rotating arm 65, which constitutes the movement mechanism for moving the exposure head 4 between the exposure position and the retracted position, is located outside the duct region of the exposure head (region La shown in Figure 20). Therefore, it does not obstruct the supply of air from below the exposure head 4 to the duct region, and air can be directly blown onto the back surface of the substrate 50 of the exposure head 4. This allows for more effective cooling of the substrate 50, including the light-emitting element of the exposure head 4.

[0179] Furthermore, the exposure head 4 is separated from the adjacent developing unit 24 and drum unit 23 by the housing support member 55 of the exposure head 4. As a result, the air used to cool the exposure head 4, which is introduced on the back surface of the substrate 50, does not leak to the side of the developing unit 24 adjacent to the exposure head 4, thereby reducing the scattering of toner inside the device.

[0180] The operation of the rotating arm 65, which moves the exposure head 4 to the exposure position or the retracted position, is powered by the sliding movement of the developing stay 31, which retracts the developing unit 24. However, power may also be obtained via another component that is linked to the inner door 102.

[0181] (Sealing properties of the exposure head) The sealing properties of the exposure head 4 will be explained using Figure 33. Figure 33 is a cross-sectional view taken along the XX arrow in Figure 20, similar to Figure 22. Figure 33 is a cross-sectional view taken from the front of the exposure head 4, the lifting duct 69, and the cartridge tray 30, without showing the drum unit 23 or the developing unit 24.

[0182] As can be seen from Figure 33, the exposure head 4 is mounted on the lifting duct 69, forming a cooling duct for the exposure head.

[0183] As described above, the housing support member 55 of the exposure head 4 is provided with engaging claws 55b1 and 55b2 for engaging with the lifting duct 69. On the other hand, the lifting duct 69 is provided with engaging holes 69b and 69c on the upper surface portion 69U facing the exposure head 4 for engaging with the engaging claws 55b1 and 55b2. Based on this configuration, the exposure head 4 can be engaged with the lifting duct 69 and integrated into one unit according to the procedure for replacing and attaching the exposure head 4 described later.

[0184] Furthermore, there is a small gap between the engaging claws 55b1 and 55b2 of the exposure head 4 and the lifting duct 69.

[0185] This gap exists in the vertical direction in Figure 59, that is, in the direction of arrow D shown in Figure 49, and is a necessary gap from the standpoint of ease of assembly and part accuracy.

[0186] Firstly, from the standpoint of ease of assembly, if this gap is absent, it will create resistance to the sliding motion in the direction of arrow B shown in Figure 52, potentially causing it to get stuck during the sliding motion and preventing it from reaching its intended position as shown in Figure 57.

[0187] Next, from the standpoint of component precision, the housing support member 55 and the lifting duct 69 have an elongated shape in the direction of movement (front-to-back direction), and it is unavoidable that a certain amount of warping occurs during the component manufacturing process.

[0188] For example, if the housing support member 55 has a curvature such that its longitudinal central portion protrudes by 0.5 mm in the direction of the lifting duct 69 relative to both ends, then unless the aforementioned gap is 0.5 mm or more, the engaging claws 55b1 and 55b2 will not engage with the edges of the engaging holes 69b and 69c in the first place.

[0189] From the above explanation, it can be seen that a predetermined amount of clearance is necessary to absorb the warping of the parts and to prevent resistance to the mounting operation of the exposure head 4 to the lifting duct 69.

[0190] However, from the perspective of the duct that supplies air to cool the exposure head 4, this gap is undesirable, as blowing or sucking through the gap could create a risk of toner scattering inside the device. Therefore, in order to reduce the aforementioned risk, the gap size must be minimized.

[0191] One possible countermeasure is to install a seal, such as a foamed sealant, in the gap. Specifically, the seal would be applied to the exposure head or lifting duct that forms the gap. However, the sliding motion of the exposure head, indicated by arrow B in Figure 52, may cause the seal to peel or detach. Furthermore, considering that the seal is located near the photosensitive drum 2 and the developing sleeve 5, and that fragments of the seal may adhere to them, it is desirable to implement a countermeasure using a method other than applying a seal.

[0192] Therefore, in this embodiment, in order to reduce this gap, the system is configured as shown in Figure 28. Figure 28 is a perspective view showing the lifting duct 69 engaged with the exposure head 4 and the rotating arm 65 engaged with the lifting duct 69.

[0193] As described above, the rotating arm 65, as the mechanism for moving the exposure head 4, presses upward the bottom surfaces of the first engaging portion 69d and the second engaging portion 69e at both longitudinal ends of the lifting duct 69 by the force of the arm pressure spring 67, which is a biasing member. Here, the bottom surfaces of the first engaging portion 69d and the second engaging portion 69e of the lifting duct 69 are the second surfaces, which are positioned opposite the first surface in the direction of movement of the lifting duct 69, if the upper surface portion 69U on which the exposure head 4 is mounted is considered the first surface. By rotating in one direction, the rotating arm 65 presses upward the bottom surfaces of the first engaging portion 69d and the second engaging portion 69e at both ends of the lifting duct 69, thereby moving the exposure head 4 to the exposure position in conjunction with the lifting duct 69 and maintaining the exposure position of the exposure head 4 relative to the photosensitive drum 2. As mentioned above, this pressure is ensured by a predetermined spring pressure provided by the arm pressure spring 67.

[0194] Thus, the rotating arm 65 does not directly press the exposure head 4, but rather presses the lifting duct 69 that supports the exposure head 4.

[0195] Furthermore, the rotating arm 65 biases the lifting duct 69 toward the photosensitive drum 2 with a predetermined spring pressure from the arm pressure spring 67, which is a biasing member. In other words, the rotating arm 65 biases the lifting duct 69 toward the housing support member 55 with a predetermined spring pressure from the arm pressure spring 67.

[0196] Here, the spring pressure from the arm pressure spring 67 is set to a sufficiently strong value. As a result, the rotating arm 65 biases the lifting duct 69 with the biasing force of the arm pressure spring 67, thereby reducing the gap between the housing support member 55 of the exposure head 4 and the lifting duct 69.

[0197] Furthermore, even if the housing support member 55 of the exposure head 4 and the upper surface portion 69U of the lifting duct 69 that engages with the housing support member 55 have a predetermined amount of warping due to the manufacturing process, the biasing force of the arm pressure spring 67 corrects the posture of both, thereby reducing the gap between the members caused by the warping.

[0198] This configuration allows for easy attachment and detachment of the exposure head 4 to the lifting duct 69, reduces assembly and component precision gaps between the exposure head 4 and the lifting duct 69, and reduces toner scattering inside the image forming apparatus.

[0199] (Duct unit) The image forming apparatus 100 is also equipped with a detachable duct unit 60. The duct unit 60 will be described with reference to Figures 35, 37, 39, and 36. Figure 35 is a perspective view of the duct unit from above. Figure 36 is a perspective view of the duct unit from below. Figure 37 is a cross-sectional view of the intake side of the exposure cooling airflow, which is a cross-sectional view taken at Y3-Y3 as shown in Figure 34. Figure 39 is a cross-sectional view of the exhaust side of the exposure cooling airflow, which is a cross-sectional view taken at Y4-Y4 as shown in Figure 34.

[0200] The duct unit 60 is an exposure cooling unit that communicates with the opening 64 formed by the cartridge tray 30 and the lifting duct 69, and cools the exposure head 4 by airflow through the lifting duct 69.

[0201] The duct unit 60 includes an intake fan 62 and an intake duct 205 for supplying air from outside the image forming apparatus to each exposure head 4. The duct unit 60 also includes an exhaust fan 63 and an exhaust duct 206 for exhausting air from each exposure head 4 to the outside of the image forming apparatus. The duct unit 60 integrates the intake fan 62, the exhaust fan 63, the intake duct 205, and the exhaust duct 206, and is detachably mounted on the main body of the image forming apparatus 100 directly below the cartridge tray 30.

[0202] The duct unit 60 includes an intake duct 205 and an exhaust duct 206 provided separately from the intake duct 205. In other words, the duct unit 60 includes an intake duct 205 as a first duct and an exhaust duct 206 as a second duct provided separately from the first duct.

[0203] The duct unit 60 is equipped with an intake port 203 and an exhaust port 204 on the same side (left side) as the image forming apparatus 100. An intake fan 62 is located at the intake port 203, and an exhaust fan 63 is located at the exhaust port 204. In this embodiment, as shown in Figure 34, the intake fan 62, located towards the front of the image forming apparatus 100, functions as an intake fan that takes in air from outside the apparatus, and the exhaust fan 63, located towards the rear, functions as an exhaust fan that exhausts air to the outside of the apparatus.

[0204] The exterior cover forming the left side of the image forming apparatus has louvers (not shown) formed as openings (first opening, second opening) opposite the respective fans 62 and 63. The louvers formed in the exterior cover communicate with the intake port 203 and exhaust port 204 where the fans 62 and 63 are located, respectively. Intake by the intake fan 62 and exhaust by the exhaust fan 63 are performed through the louvers formed in the exterior cover forming the left side of the image forming apparatus.

[0205] As shown in Figures 35 and 37, the duct unit 60 has a third opening 201 (Y, M, C, K) on its upper surface, located towards the front of the image forming apparatus 100, for each exposure head. The intake port 203 and each of the openings 201 (Y, M, C, K) for each exposure head are connected by an intake duct 205. The duct unit 60 is configured to draw in air from outside the image forming apparatus (fresh air) through the intake port 203 using an intake fan 62 and discharge it through each of the openings 201.

[0206] As shown in Figures 35 and 39, the duct unit 60 has a fourth opening 202 (Y, M, C, K) on its upper surface, located towards the rear of the image forming apparatus 100, for each exposure head. The exhaust port 204 and each opening 202 for each exposure head are connected by an exhaust duct 206. The duct unit 60 is configured to use an exhaust fan 63 to draw in air from each opening 202 and discharge it to the outside of the image forming apparatus through the exhaust port 204.

[0207] In this embodiment, due to the convenience of part molding, the duct unit 60 is composed of two parts, an upper frame 60a and a lower frame 60b, which are divided vertically, as shown in Figures 35 and 36. Here, the duct unit 60 is fixed by snap-fitting the outer edges of the upper frame 60a and the lower frame 60b in the front-rear direction, and also by snap-fitting the parts that straddle the intake duct 205 and the exhaust duct 206. Here, fixing the parts that straddle the intake duct 205 and the exhaust duct 206 means that the part of the upper frame 60a between the intake duct 205 and the exhaust duct 206 is fixed by snap-fitting the part of the lower frame 60b that is opposite to the part of the upper frame 60a between the intake duct 205 and the exhaust duct 206. By fixing the upper frame 60a and the lower frame 60b together using snap fittings, airflow leakage from the gaps in the dividing surfaces of the intake duct 205 and exhaust duct 206 is suppressed.

[0208] As shown in Figure 35, the duct unit 60 has openings 61 (Y, M, C, K) on its upper surface. The openings 61 of the duct unit 60 include a third opening 201 located towards the front of the device and a fourth opening 202 located towards the rear of the device. The openings 61 (Y, M, C, K) of the duct unit 60 are provided to correspond to each of the exposure heads 4 of each color.

[0209] In other words, the opening 60Y of the duct unit 60 includes an opening 201Y provided towards the front of the device and an opening 202Y provided towards the rear of the device. The opening 60M of the duct unit 60 includes an opening 201M provided towards the front of the device and an opening 202M provided towards the rear of the device. The opening 60C of the duct unit 60 includes an opening 201C provided towards the front of the device and an opening 202C provided towards the rear of the device. The opening 60K of the duct unit 60 includes an opening 201K provided towards the front of the device and an opening 202K provided towards the rear of the device.

[0210] The opening 61 of the duct unit 60 is positioned opposite the opening 64 formed by the lifting duct 69 and the cartridge tray 30, and is connected to the opening 64 by being pressed against it, forming a closed space.

[0211] (Configuration of sealing members in duct units) As explained earlier, as shown in Figure 37, the exposure cooling airflow flows from the third opening 201 of the duct unit 60 to the first opening 73 which is connected to it, and as shown in Figure 39, from the fourth opening 202 to the second opening 74 which is connected to it. In other words, the exposure cooling airflow flows from the opening 61 of the duct unit 60, which includes the third opening 201 and the fourth opening 202, to the cartridge tray 30 and the lifting duct 69, which include the first opening 73 and the second opening 74 which are connected to it. Therefore, in order to prevent toner scattering due to airflow leakage and a decrease in cooling efficiency due to pressure loss of the airflow, it is desirable to seal the gaps between each opening.

[0212] As shown in Figures 26 and 38, it is desirable that the gap between the opening 64 formed by the cartridge tray 30 and the lifting duct 69 and the opening 61 of the duct unit 60 that communicates with it be sealed.

[0213] Therefore, in this embodiment, as shown in Figure 35, a sealing member 207 is provided to surround the third opening 201 and the fourth opening 202 of the duct unit 60. The sealing member 207 is made of an elastic material such as sponge or rubber made of urethane or silicone. Figure 21 is a schematic view of the cartridge tray 30 and the lifting duct 69 from below. In Figure 21, the opening 64 formed by the cartridge tray 30 and the lifting duct 69 is shown with hatching.

[0214] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 is formed by the developing support member 301, the drum support member 302, and the lifting duct 69 between the developing support member 301 and the drum support member 302, as shown in Figure 21. More specifically, the opening 64 is formed by the developing guide portion 301a of the developing support member 301, the drum guide portion 302a of the drum support member 302, and the front wall 69F and rear wall 69B of the lifting duct 69 between the developing guide portion 301a and the drum guide portion 302a.

[0215] On the upper surface of the duct unit 60, a sealing member 207 is provided so as to surround all four sides of each opening 61, including the opening (exhaust port) 201 of the intake duct 205 and the opening (intake port) 202 of the exhaust duct 206.

[0216] Of these, the sealing member 207 provided on the upper surface of one longitudinal side of the opening 61 of the duct unit 60 is sandwiched between the developing guide portion 301a of the developing support member 301 by the pressure of the duct unit 60. The sealing member 207 provided on the upper surface of one longitudinal side of the opening 61 of the duct unit 60 extends from the opening 201 on one side (front side) to the opening 202 on the other side (rear side) in the front-rear direction.

[0217] The sealing member 207 provided on the upper surface of the other longitudinal side of the opening 61 of the duct unit 60 is sandwiched between the drum guide portion 302a of the drum support member 302 by the pressure of the duct unit 60. The sealing member 207 provided on the upper surface of the other longitudinal side of the opening 61 of the duct unit 60 is also provided extending from the opening 201 on one side (front side) to the opening 202 on the other side (rear side) in the front-rear direction.

[0218] The sealing member 207, provided on the upper surface of one of the shorter sides of the opening 61 of the duct unit 60, comes into contact with the side surface of the front wall 69F of the lifting duct 69 when pressed by the duct unit 60. The side surface of the front wall 69F of the lifting duct 69 that the sealing member 207 contacts is the surface that faces the side surface of the rear wall 69B of the duct in the front-rear direction.

[0219] The sealing member 207, provided on the upper surface of the other side in the shorter direction of the opening 61 of the duct unit 60, comes into contact with the rear wall 69B of the lifting duct 69 when pressed by the duct unit 60. The side surface of the rear wall 69B of the lifting duct 69 that contacts the sealing member 207 is the surface that faces the side surface of the front wall 69F of the duct in the front-rear direction.

[0220] The reason why the sides of the duct front wall 69F and the duct rear wall 69B are in contact with the sides of the sealing member 207 is as follows: The lifting duct 69 is moved between the exposure position shown in Figure 22 and the retracted position shown in Figure 23 by the rotation of the rotating arm 65, and this movement is to be prevented from being obstructed by the duct unit 60.

[0221] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 communicates with the opening 55a of the exposure head 4, which is integrally supported by the lifting duct 69. When the duct unit 60 is mounted on the image forming apparatus 100, the opening 61 of the duct unit is pressed against the opening 64 formed by the cartridge tray 30 and the lifting duct 69, and the opening 64 and the opening 61 communicate with each other. This forms a closed space called a duct from the duct unit 60 through the cartridge tray 30 and the lifting duct 69 to the exposure head 4.

[0222] In this manner, the sealing member 207 is pressed between the opening 61 of the duct unit 60 and the developing guide section 301a and drum guide section 302a, causing the side surface of the sealing member 207 to be in close contact with the side surface of the duct front wall 69F and the side surface of the duct rear wall 69B, thereby sealing the gap. That is, the gap between the opening 61 of the duct unit 60 and the opening 64 formed by the cartridge tray 30 and the lifting duct 69 is sealed by the sealing member 207. This prevents toner scattering due to airflow leakage and a decrease in cooling efficiency due to airflow pressure loss.

[0223] (Assembly and removal of duct units) The configuration for assembling and detaching the duct unit 60 to the image forming apparatus 100 will be explained using Figures 2, 35, 37, 38, 21, 40, 41, and 36. Figure 37 is a cross-sectional view showing the state in which the duct unit 60 is assembled to the image forming apparatus 100. Figure 40 is a cross-sectional view showing the state immediately before the duct unit 60 is assembled to the image forming apparatus 100 or immediately after it has been removed. Figure 41 is a partial enlargement view of Figures 37 and 40. Figure 36 is a perspective view of the duct unit 60 viewed from the lower right front direction.

[0224] The duct unit 60 is inserted into the image forming apparatus 100 from one side (the left side in this case) towards the other, and at the timing of positioning, it is moved from below to above by guides (guide section 103, support section 104) inside the apparatus. At this time, the opening 61 of the duct unit 60 is pressed (engaged) by the opening 64 formed by the cartridge tray 30 and the lifting duct 69, and an air passage is formed in which the opening 64 and the opening 61 are connected. The following will be explained with reference to the drawings.

[0225] As mentioned above, the duct unit 60 presses and tightly seals the sealing member 207 between itself and the cartridge tray 30 and the lifting duct 69, thereby sealing the gap and preventing toner scattering due to airflow leakage and a decrease in cooling efficiency due to pressure loss of the airflow. For this reason, it is desirable that the duct unit 60 be assembled to the components assembled to the image forming apparatus 100, such as the cartridge tray 30, so as to rise from approximately below.

[0226] On the other hand, as shown in Figure 2, a sheet cassette 12 is positioned below the duct unit 60, making it difficult to simply assemble the duct unit 60 to the image forming apparatus 100 from below due to the arrangement of each unit. Therefore, in this embodiment, the duct unit 60 is assembled from the side of the image forming apparatus 100, and is configured to rise slightly at the same time as insertion from the side just before the assembly position.

[0227] In this case, it is preferable to assemble the duct unit 60 from the left side of the image forming apparatus 100. This is because the right side of the image forming apparatus 100 houses rollers and guides involved in the transport of the recording paper P, and assembling the duct unit 60 requires the removal of these transport rollers and guides, thus avoiding assembly from the right side.

[0228] As shown in Figures 37, 41(a), and 41(b), the supported portion 209 on the lower surface of the duct unit 60 is supported by a support portion 104 formed on the image forming apparatus 100. The upper surface of the duct unit 60 receives a downward reaction force via a sealing member 207, thereby restricting its height. In this embodiment, the support portion 104 is provided on a part of the sheet metal 100C that bridges between the front plate 100F and the rear plate 100B, which constitute part of the frame (housing) of the image forming apparatus. The supported portion 209 is provided at two locations each on the right and left ends of the duct unit 60 in the front-to-back direction, for a total of four locations. As a result, the duct unit 60 is free from tilt and distortion relative to the image forming apparatus 100, ensuring reliable communication with the openings of each color on the image forming apparatus side and allowing air to circulate.

[0229] At this time, the opening 64 and the opening 61 face each other, and the gap between the opening 64 and the opening 61 is sealed by the sealing member 207.

[0230] As shown in Figures 37, 41(a), and 41(b), the duct unit 60 is fixed to the image forming apparatus 100 by fastening members 211 at the fastening portion 210 of the duct unit 60 to the fastening portion 105 of the sheet metal 100C. As shown in Figure 35, the fastening portion 210 is provided at two locations on the left end of the duct unit 60, and is positioned near the intake fan 62 and the exhaust fan 63. The fastening portion 105 is provided at two locations on the left end of the sheet metal 100C, and is positioned opposite the fastening portion 210 in the insertion and removal direction of the duct unit 60. As a result, the intake fan 62 and the exhaust fan 63 are firmly fixed to the image forming apparatus 100, and the occurrence of rattling noise due to vibration and the occurrence of image defects such as streaks due to the transmission of vibration to the drum 2, etc., can be suppressed.

[0231] As shown in Figures 40, 41(c), and 41(d), immediately before the duct unit 60 is assembled to the image forming apparatus 100, or immediately after it is removed, the sealing member 207 is spaced apart in the height direction from the cartridge tray 30 and the lifting duct 69. Therefore, the sealing member 207 of the duct unit 60 does not slide against the image forming apparatus 100, and the duct unit 60 can be easily assembled to and removed from the image forming apparatus 100. At this time, the guided portion 208 of the duct unit 60 is in contact with the guide portion 103 of the image forming apparatus 100. In this embodiment, the guide portion 103 is formed as a curved surface continuous with the support portion 104, and the guided portion 208 is formed as an inclined surface with respect to the assembly direction of the duct unit 60, continuous with the supported portion 209. As a result, by assembling the duct unit 60 from the left side of the image forming apparatus 100 toward the right, it naturally traces a trajectory toward the upper right, transitioning to the assembly state shown in Figures 37, 41(a), and 41(b).

[0232] Then, when the exposure cooling unit, the duct unit 60, is inserted into the image forming apparatus 100, it is guided by the guided portion 208, which has an inclined portion that slopes along the insertion direction, and moves upward and to the right. As a result, the sealing member 207 is compressed and tightly adhered to the cartridge tray 30 and the lifting duct 69, sealing the gap between the opening 64 and the opening 61.

[0233] (Intake and exhaust ports of the duct unit) Next, the intake fan 62 and exhaust fan 63 of the duct unit 60 will be described in more detail.

[0234] The exposure cooling airflow is formed as a separate path from the overall view of the developer cooling airflow shown in Figure 34, and from the paths of the developer cooling airflow as can be seen in Figures 22 and 37. Therefore, toner leaking from the developer unit 24 does not mix with the exposure cooling airflow, reducing the risk of toner scattering inside the device.

[0235] Furthermore, the airflow is made compact by arranging the intake port 203 and exhaust port 204 of the exposure cooling airflow on the same side of the image forming apparatus body. In addition, by arranging the intake port 203 and exhaust port 204 of the exposure cooling airflow on different sides from the intake port 101a and exhaust port of the development cooling airflow, mutual influence with the development cooling airflow can be minimized.

[0236] For example, in this embodiment, the exhaust port for the developing and cooling airflow is located on the rear of the device body, while the intake port 203 for the exposure and cooling airflow is located on the left side of the device body. As a result, the exposure and cooling airflow hardly takes in any of the heat generated during image formation by the developing process, and vice versa.

[0237] Even when the temperature rise conditions of the developing unit 24 and the exposure head 4 differ due to an image or a paper path mode, the cooling paths and fans of the exposure cooling means and the developing cooling means are separate. Therefore, it is possible to perform optimal cooling for each, and high degrees of freedom in air flow control and efficient control can be achieved.

[0238] (Configuration of the fans of the duct unit) Here, the details of the arrangement of the intake fan 62 and the exhaust fan 63 will be described with reference to FIG. 42.

[0239] FIG. 42 is a cross-sectional view of the duct unit as viewed from above the image forming apparatus in the direction of the arrow F - F in FIGS. 37 and 39. In FIG. 42, the arrangements of the intake fan 62 and the exhaust fan 63, which were simply shown in FIG. 34, are shown in detail.

[0240] In FIG. 42, the intake fan 62 is arranged at an angle θF with respect to the direction perpendicular to the left side surface of the image forming apparatus 100, that is, with respect to the longitudinal direction of the intake duct 205 and the exhaust duct 206. Similarly, the exhaust fan 63 is arranged at an angle θR with respect to the longitudinal direction of the intake duct 205 and the exhaust duct 206. As a result, the intake direction by the intake fan 62 is a direction from one end side in the longitudinal direction of the substrate 50 toward the central side in the longitudinal direction, and the exhaust direction by the exhaust fan 63 is a direction from the central side in the longitudinal direction of the substrate 50 toward the other end side in the longitudinal direction. And, as shown by the arrows in FIG. 42, the angles θF and θR are angles such that the intake angle by the intake fan 62 and the exhaust angle by the exhaust fan 63 are in directions opposite to each other (upward, downward) with respect to the horizontal. For this reason, it can be said that the intake of fresh air by the intake fan 62 makes it difficult to take in the heat contained in the exhaust of the exhaust fan 63, contributing to suppressing a decrease in the cooling efficiency due to the circulation of the exposure cooling air flow.

[0241] In Figure 42, angles θF and θR are set as relative angles such that they are diagonally upward and diagonally downward, but they may also be set as relative angles such that they are diagonally left and diagonally right. Alternatively, a combination of these relative angles may be used. That is, it is preferable to set the relative angles such that the intake central axis and the exhaust central axis do not intersect outside the image forming apparatus 100, and that the intake central axis and the exhaust central axis diverge as the distance from the image forming apparatus 100 increases.

[0242] As described above, by attaching a fan to the duct unit 60, it is possible to reduce toner scattering into the image forming apparatus and provide a highly efficient and flexible cooling method for the LED exposure apparatus.

[0243] (Cooling configuration of the developing unit) Next, the cooling configuration of the developing unit 24 will be explained using Figure 34. Figure 34 is a cross-sectional view of the image forming apparatus as seen through the AA arrow in Figure 2. In Figure 34, the airflow for cooling the developing unit 24 is shown by a dashed line. The airflow shown by the dashed line in Figure 34 is also called the developing cooling airflow.

[0244] As described above, the developing unit 24 contains a screw 7 that rotates at high speed and toner that circulates at high speed. This operation generates frictional heat in the bearing of the screw 7 and the toner, and this frictional heat is stored in the developing unit 24, causing its temperature to rise. Once image formation is complete, the developing unit 24 stops accumulating heat and gradually cools down. However, as long as image formation continues, heat is accumulated as far as the heat capacity of the developing unit 24 allows, and its temperature rises. Because toner is easily melted by heat, if the developing unit 24 rises above a certain temperature, the toner fuses inside the developing unit 24, resulting in a coating defect on the developing sleeve 5, distorting the toner image, and leading to an image defect.

[0245] Therefore, a cooling configuration for the developing unit 24 is necessary to prevent the developing unit 24 from rising above a certain temperature.

[0246] The image forming apparatus 100 includes a fan 40 and a front duct 41 for supplying air from outside the apparatus to each developing unit 24. The image forming apparatus 100 also includes a rear duct 42 for exhausting air from each developing unit 24 to the outside of the apparatus and a toner filter 43. The image forming apparatus 100 has a duct formed by the developing unit 24 and the cartridge tray 30.

[0247] The duct formed axially in the direction of the photosensitive drum between the developing unit 24 and the cartridge tray 30 is located between a front duct 41 located on the front side of the device and a rear duct 42 located on the rear side of the device. The duct formed axially in the direction of the photosensitive drum between the developing unit 24 and the cartridge tray 30 has one axial end on the front side of the device that communicates with the front duct 41, and the other axial end on the rear side of the device that communicates with the rear duct 42, forming a closed space.

[0248] The fan 40 is located on the right side of the front of the main body of the image forming apparatus 100 and draws in air from outside the apparatus through an air intake port 101a located on the right side of the front cover 101 of the image forming apparatus 100. The front duct 41 is located inside the front cover 101 and extends in the left-right direction, which is the direction in which the developing units 24 are arranged. The front duct 41 has openings 41a at positions corresponding to each developing unit 24. The openings 41a of the front duct 41 are located in the axial direction of the photosensitive drum and are positioned opposite to the openings 102c of the inner doors 102 of each cartridge tray 30, and they communicate with each other when the front cover 101 is closed. The openings 102c of each inner door 102 are located at positions corresponding to the openings at one end in the longitudinal direction of the closed space formed between the developing unit 24 and the developing support member 301, and they communicate with each other when the inner doors 102 are closed.

[0249] The rear duct 42 has openings 42a at positions corresponding to each developing unit 24. The openings 42a of the rear duct 42 are located in the axial direction of the photosensitive drum and correspond to the openings at the other end of the closed space formed between the developing unit 24 and the developing support member 301 in the longitudinal direction, and are in communication with each other.

[0250] Thus, the duct, which is a closed space formed between the developing unit 24 and the cartridge tray 30, forms part of a single closed space that communicates with the front duct 41 and the rear duct 42. The duct formed between the developing unit 24 and the cartridge tray 30, along with the front duct 41 and the rear duct 42 that communicate with it, form the first cooling duct, which is the single closed space that serves as the flow path for the developing cooling airflow.

[0251] The first cooling duct forms a closed space that serves as a flow path for the developing cooling airflow that cools the developing unit 24. In other words, the first cooling duct is a developing cooling means that cools the developing unit, which is a developing means. However, the first cooling duct, which is a developing cooling means, only needs to be partly formed by the duct, which is a closed space formed between the developing unit 24 and the cartridge tray 30, and the other configurations are not limited to those described above.

[0252] Each developing unit 24 is cooled by a developing and cooling airflow (shown as a dashed line in Figure 34) flowing through the aforementioned closed space.

[0253] The developing and cooling airflow shown by the dashed line in Figure 34 is first generated by the fan 40 located in front of the right side of the image forming apparatus and the first cooling duct, which is the aforementioned enclosed space.

[0254] When the fan 40 rotates, air from outside the apparatus is drawn in through the intake port 101a of the front cover 101 located on the right side of the image forming apparatus 100, and sent to the developing unit 24, which is to be cooled, via the opening 41a of the front duct 41 located inside the front cover 101 and the opening 102c of the inner door 102.

[0255] The air supplied to the developing unit 24 is taken in through the front opening in the front-to-back direction of the duct formed between the developing unit 24 and the cartridge tray 30, sent along the axial direction of the photosensitive drum, and exhausted through the rear opening in the front-to-back direction.

[0256] The air exhausted from the rear side in the front-to-back direction of the duct formed between the developing unit 24 and the cartridge tray 30 passes through the opening 42a of the rear duct 42, then passes through the toner filter 43, and is exhausted to the outside of the device from the rear of the device.

[0257] Now, let's describe the toner filter 43. The toner filter 43 is located in the rear duct 42, directly in front of the exhaust port at the rear of the device. Since the developing and cooling airflow is an airflow that passes around the developing unit 24, it is unavoidable that a small amount of toner will be taken into the airflow. Therefore, it is desirable to place the toner filter 43 directly in front of the exhaust port of the developing and cooling airflow to prevent even a small amount of toner from being discharged outside the device.

[0258] In general, cooling by airflow primarily involves using inexpensive fans to create airflow, and the same applies to airflow other than developing and cooling.

[0259] (Cooling configuration for exposure head) Next, the cooling configuration of the exposure head 4 will be explained using Figure 34. In Figure 34, the airflow for cooling the exposure head 4 is shown by a dashed line. The airflow shown by the dashed line in Figure 34 is also called the exposure cooling airflow.

[0260] Since the exposure head 4 dissipates heat according to the amount of light emitted by the LED (light-emitting element) 51 and is disposed in proximity to the developing unit 24 that uses toner vulnerable to heat, a cooling means is required. In particular, when used in an apparatus that repeats the image forming process frequently, i.e., an apparatus with high productivity, or when continuously outputting images with high density, etc., the light emission time is long and the amount of light emitted is large. Therefore, the amount of heat generated from the LED 51 and the circuits on the substrate 50 on which it is mounted also increases.

[0261] As a countermeasure against this, for example, the housing 54 of the exposure head 4 is also utilized as a heat dissipation plate, and the exposure head 4 is configured to be easily cooled and difficult to store heat. However, even in such a case, it is conceivable that the cooling of the exposure head 4 is insufficient and heat storage progresses, increasing the heat dissipated to the surroundings. As a result, part of the toner around the developing sleeve 5 provided in the developing unit 24 and the circulating toner inside the developing unit 24 may fuse, affecting the toner coat layer on the surface of the developing sleeve 5 and resulting in image defects.

[0262] Even when the developing unit 24 is provided with a cooling configuration, it is easily assumed that heat storage due to the light emission of the LED 51 prevails in the portion of the developing unit 24 close to the exposure head 4. Therefore, separately from the cooling configuration of the developing unit 24 (developing cooling air flow), it is desirable to provide a cooling configuration (exposure cooling air flow) for the exposure head 4 to cool the exposure head 4 and exhaust heat to the outside of the apparatus, in order to suppress the amount of heat dissipated around the exposure head 4.

[0263] Furthermore, as shown in Figure 8, the developing unit 24 and the developing sleeve 5 attached to the developing unit 24 are positioned adjacent to the exposure head 4. The developing sleeve 5 is coated with toner on its surface, and due to its structure, toner adheres to the vicinity of the bearings at both ends of the sleeve, as well as toner around the developing unit 24. This is because the developing sleeve 5 and screw 7 rotate at high speed, causing the agitated toner to fly up and peel off from the surfaces of the developing sleeve 5 and screw 7. In addition, the increase in internal pressure of the developing unit 24 due to the high-speed rotation of the developing sleeve 5 and screw 7 can cause toner to be ejected to the outside through gaps in the developing unit 24.

[0264] Therefore, it is desirable that the cooling configuration of the exposure head 4 be such that it does not involve or mix in these toners. In other words, when configuring the exposure cooling airflow separately from the development cooling airflow, it is desirable that it be such that it does not involve or mix in the toners from around the development unit 24 adjacent to the exposure head 4.

[0265] The image forming apparatus 100 includes an exposure head 4, a lifting duct 69, a cartridge tray 30, and a duct unit 60. The exposure head 4 is mounted on the lifting duct 69 located in the image forming apparatus 100 and becomes integrated with the lifting duct 69. By mounting the exposure head 4 on the lifting duct 69, the opening 55a of the housing support member 55 of the exposure head 4 communicates with the opening 69a of the lifting duct 69. The lifting duct 69 is positioned between the first development guide section 301a and the first drum guide section 302a of the cartridge tray 30, and together with the cartridge tray 30, forms a duct that connects the exposure head 4 and the duct unit 60. The duct unit 60 is mounted on the image forming apparatus 100. When the duct unit 60 is mounted on the image forming apparatus 100, the opening 61 of the duct unit 60 communicates with the opening 64 formed by the lifting duct 69 and the cartridge tray 30.

[0266] In this way, the housing support member 55 of the exposure head 4, the lifting duct 69, the cartridge tray 30, and the duct unit 60 form a second cooling duct, which is a continuous closed space. Each exposure head 4 is cooled by the exposure cooling airflow (dashed line shown in Figure 34) flowing through the closed space formed by the housing support member 55, the lifting duct 69 communicating with it, and the duct unit 60 communicating with the lifting duct and the cartridge tray 30.

[0267] The second cooling duct, which is a closed space that serves as the flow path for the exposure cooling airflow and is shown by a dashed line in Figure 34, is configured separately from the first cooling duct, which is a closed space that serves as the flow path for the development cooling airflow and is shown by a dashed line in Figure 34.

[0268] The first cooling duct, which circulates airflow to cool the developing unit 24, and the second cooling duct, which circulates airflow to cool the exposure head 4, are separated by the first developing guide section 301a and the lifting duct 69 of the developing support member 301. In other words, the first developing guide section 301a and the lifting duct 69 of the developing support member 301 separate the first cooling duct, which circulates airflow to cool the developing unit 24, from the second cooling duct, which circulates airflow to cool the exposure head, between the exposure head 4 and the developing unit 24.

[0269] The second cooling duct forms a closed space that serves as a flow path for the exposure cooling airflow that cools the exposure head 4. In other words, the second cooling duct is an exposure cooling means that cools the exposure head, which is an exposure means. However, the second cooling duct, which is an exposure cooling means, is not limited to the above configuration, as long as a separate closed space is formed from the first cooling duct by the lifting duct 69, which is an exposure support member, the cartridge tray 30, which is a support member, and the duct unit 60, which is an exposure cooling unit.

[0270] As described above, the duct unit 60, cartridge tray 30, lifting duct 69, and housing support member 55 form a continuous closed space, thereby constituting the exposure cooling airflow. As shown in Figure 35, the intake fan 62 and exhaust fan 63 of the duct unit 60 face the outside of the device only through the device's outer cover. The flow path of the exposure cooling airflow is completed in the shortest possible path, formed by directly drawing air into the duct unit 60 from the louvers of the outer cover and directly exhausting it from the duct unit 60. Therefore, the intake and exhaust flow is configured to have little effect on the atmospheric air inside the device.

[0271] Furthermore, a finisher is available as an option on the paper output side of the image forming apparatus 100. When installed, the finisher blocks almost the entire left side of the image forming apparatus 100, which is faced by the intake fan 62 and exhaust fan 63. In this case, the intake and exhaust of air by the intake fan 62 and exhaust fan 63 will be directed into the interior of the finisher, but the interior of the finisher has many cavities. Therefore, the louvers (not shown) of the exterior cover are positioned to avoid facing the main structure inside the finisher. This makes it possible to suppress the degradation of exposure cooling airflow performance to a level that does not cause problems in practical use.

[0272] (Sealing configuration using sealing member) Next, using Figures 22 and 23, we will describe the sealing configuration of a first cooling duct, which is a closed space that serves as a flow path for the developing cooling airflow, and a second cooling duct, which is provided separately from the first cooling duct and serves as a flow path for the exposure cooling airflow.

[0273] Specifically, we will describe a sealing configuration in which the gap between the cartridge tray 30 and the lifting duct 69 is sealed by seals 71 and 72, which are sealing members, and a sealing configuration in which the gap between the developing unit 24 and the cartridge tray 30 is sealed by seal 70, which is a sealing member.

[0274] As shown in Figures 37 and 39, the cartridge tray 30, the lifting duct 69, and the housing support member 55 form a second cooling duct, and exposure cooling airflow is configured for the back surface of the substrate 50 on which the LED 51 is mounted, through the opening 55a of the housing support member 55.

[0275] The entire width of the lower surface of the lifting duct 69 is open, ensuring maximum airflow to the substrate 50 positioned directly above it, which is advantageous for cooling the exposure head 4.

[0276] Furthermore, if the substrate 50 has a shape that extends long in the axial direction of the photosensitive drum 2, cooling efficiency is better when the exposure cooling airflow flows perpendicular to the longitudinal direction of the substrate 50 rather than parallel to the longitudinal direction of the substrate 50. In the duct cross-section shown in Figure 37, the airflow flowing inside the second cooling duct is configured to be approximately perpendicular to the longitudinal direction of the substrate 50, which is the object to be cooled. This configuration is also advantageous for cooling in terms of the angle of the exposure cooling airflow.

[0277] In the second cooling duct, the cartridge tray 30 and the lifting duct 69 form a portion of the duct. The gap between the cartridge tray 30 and the lifting duct 69 that forms this portion of the duct is sealed by seals 71 and 72, preventing airflow from leaking to the outside of the duct.

[0278] In other words, the image forming apparatus 100 includes seals 71 and 72, which are sealing members that seal the gap between the cartridge tray 30 and the lifting duct 69.

[0279] In the state shown in Figure 22, where the exposure head 4 is in the exposure position, the gap between the lifting duct 69 that integrally supports the exposure head 4 and the developing support member 301 of the cartridge tray 30 is sealed by a sealing member, which is a seal 72.

[0280] Furthermore, when the exposure head 4 is in the exposure position, the gap between the lifting duct 69 that integrally supports the exposure head 4 and the drum support member 302 of the cartridge tray 30 is sealed by a sealing member, which is a seal 71.

[0281] The seal 72 is provided on the first inclined surface 69L1 of the left wall 69L of the lifting duct 69, which is the side wall of the lifting duct 69 on the developing unit 24 side. As shown in Figures 27 and 28, the seal 72 is provided on the first inclined surface 69L1 of the left wall 69L of the duct, extending longitudinally over a range La from the front wall 69F of the duct to the rear wall 69B of the duct. At the exposure position of the exposure head 4, the seal 72 seals the gap between the first inclined surface 69L1 of the left wall 69L of the lifting duct 69 and the opposing portion 301d of the first developing guide portion 301a of the developing support member 301 that faces it. Here, a configuration in which the seal 72 is provided on the lifting duct 69 side is illustrated, but a configuration in which it is provided on the developing support member 301 side is also possible.

[0282] The seal 71 is provided on the second inclined surface 69R1 of the right duct wall 69R, which is the side wall of the lifting duct 69 on the drum unit 23 side. The seal 71 is provided on the second inclined surface 69R1 of the right duct wall 69R in the longitudinal direction, extending over a range La from the front duct wall 69F to the rear duct wall 69B. At the exposure position of the exposure head 4, the seal 71 seals the gap between the second inclined surface 69R1 of the right duct wall 69R of the lifting duct 69 and the opposing portion 302d of the first drum guide portion 302a of the drum support member 302 that faces it. Here, a configuration in which the seal 71 is provided on the lifting duct 69 side is illustrated, but a configuration in which it is provided on the drum support member 302 side is also possible.

[0283] Figure 24 shows the exposure head 4 positioned in close proximity to the photosensitive drum 2. That is, the exposure head 4 is positioned in the exposure position relative to the photosensitive drum 2. As mentioned above, this is maintained by the rotating arm 65 pressing upward on the bottom surfaces of both ends of the lifting duct 69. This pressure is ensured by a predetermined spring pressure from the arm pressure spring 67, which is a torsion coil spring. In other words, when the exposure head 4 is in the exposure position as shown in Figures 22 and 24, the seals 71 and 72 are crushed by the pressure of the lifting duct 69 against the developing support member 301 and the pressure of the lifting duct 69 against the drum support member 302, ensuring the sealing of the gap.

[0284] On the other hand, when retracting the exposure head 4 from the photosensitive drum 2, as shown in Figure 25, the rotation of the rotating arm 65 in the direction of retraction from the photosensitive drum 2 is the starting point. As a result, the engaging boss 66 provided at the tip of the rotating arm 65 pushes down the engaging ribs 69d1 and 69e1 located at the lower end of the lifting duct 69, thereby retracting the exposure head 4, which is integrated with the lifting duct 69, from the photosensitive drum 2.

[0285] As shown in Figures 25 and 23, when the exposure head 4 is in the retracted position, seals 71 and 72 are separated from the developing support member 301 and drum support member 302 with which they abut, respectively, and the sealing of the gap is released.

[0286] In other words, when the exposure head 4 is moved to the retracted position, the lifting duct 69 moves in a direction that widens the gap between it and the developer support member 301 and the drum support member 302 compared to the gap at the exposure position. That is, when the exposure head 4 is moved to the retracted position, the seals 71 and 72 move away from the developer support member 301 and the drum support member 302, causing them to separate and releasing the seal over the gap.

[0287] Thus, at the exposure position of the exposure head 4, the gap between the cartridge tray 30 and the lifting duct 69 is sealed over a longitudinal range La by sealing members, seals 71 and 72. As a result, the air flowing to the exposure head 4 through the gap between the cartridge tray 30 and the lifting duct 69 does not leak from the aforementioned gap into the space around the developing unit 24 and the developing sleeve 5. Furthermore, the air flowing to the exposure head 4 through the gap between the cartridge tray 30 and the lifting duct 69 does not leak from the aforementioned gap into the space around the photosensitive drum 2 and the charging roller 3. Therefore, the possibility of toner mixing into the exposure cooling airflow, which is the airflow used to cool the exposure head 4, is small, and toner scattering into the image forming apparatus can be reduced.

[0288] Furthermore, the development cooling airflow is guided in the front-rear direction by a duct formed between the development unit 24 and the cartridge tray. In the first cooling duct, the duct formed between the cartridge tray 30 and the development unit 24 forms a portion of the first cooling duct. The gap between the cartridge tray 30 and the development unit 24 that forms this portion of the duct is sealed by a seal 70, preventing the development cooling airflow from leaking in the direction of the development sleeve 5.

[0289] In other words, the image forming apparatus 100 includes a seal 70, which is a sealing member that seals the gap between the cartridge tray 30 and the developing unit 24.

[0290] At the pressing position of the developing unit 24 shown in Figure 22, the gap between the developing unit 24 and the developing support member 301 separating the developing unit 24 from the exposure head 4 is sealed by a sealing member, which is a seal 70.

[0291] The seal 70 is provided on the first development guide portion 301a of the development support member 301, which separates the development unit 24 from the exposure head 4. The seal 70 is provided in the area between the frame of the development unit 24 and the first development guide portion 301a of the development support member 301, where the area narrows as the development unit 24 moves toward the development position. Here, the seal 70 is provided on the end (partition wall portion 301e) of the first development guide portion 301a of the development support member 301 on the development roller side when the development unit 24 is in the development position. The seal 70 is provided on the part of the partition wall portion 301e of the development support member 301 that faces the frame of the development unit 24. The seal 70 is provided on the first development guide portion 301a of the development support member 301, extending from one end in the longitudinal direction to the other end. The seal 70 seals the gap between the partition wall portion 301e, which is the end of the developing support member 301 on the developing roller side, and the frame of the developing unit 24 that faces it. Here, a configuration in which the seal 70 is provided on the developing support member 301 side is illustrated, but a configuration in which it is provided on the developing unit 24 side is also possible.

[0292] As shown in Figure 31, the developing stay 31 slides forward F in conjunction with the closing of the inner door 102. At this time, the developing unit 24 moves upward (arrow U) along the slopes of the developing pressure blocks 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves closer to the photosensitive drum 2 of the drum unit 23, and the developing sleeve 5 is pressed against the photosensitive drum 2.

[0293] When the developing unit 24 is moved to the developing position shown in Figures 22 and 24, it moves in a direction that narrows the gap between it and the first developing guide portion 301a of the developing support member 301 that separates it from the exposure head 4. In other words, as the developing unit 24 moves to the developing position shown in Figures 22 and 24, the seal 70 is crushed by moving in a direction that brings the developing unit 24 closer to the developing support member 301, thereby sealing the gap.

[0294] Furthermore, as shown in Figure 32, the developing stay 31 slides backward B in conjunction with the opening of the inner door 102. At this time, the developing unit 24 moves downward (arrow D) along the slope of the developing pressure slabs 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves to a position further away from the photosensitive drum 2 of the drum unit 23 than it does during development.

[0295] When the developing unit 24 is moved to the retracted position shown in Figures 25 and 23, the gap between it and the first developing guide portion 301a of the developing support member that separates it from the exposure head 4 is widened compared to the gap shown in Figure 22. That is, in the retracted position of the developing unit 24 shown in Figures 25 and 23, the seal 70 is separated by moving away from the developing support member 301 and the developing unit 24, and the sealing of the gap is released.

[0296] Thus, when the developing unit 24 is in the developing position, the seal 70 seals the gap between the developing sleeve side end (partition wall portion 301e) of the developing support member 301 and the frame of the developing unit 24 facing it. As a result, air flowing between the developing unit 24 and the cartridge tray 30 does not leak out of the aforementioned gap towards the developing sleeve 5.

[0297] The developing and cooling airflow flows around the developing unit 24, as shown by the dashed line in Figure 34, and may contain trace amounts of toner. Therefore, by shielding the paths between the airflows in this way, toner will not be introduced from the developing and cooling airflow. Considering that the exposure and cooling airflow is composed of the shortest possible path through which the duct directly draws in and exhausts air to and from the outside of the device, the possibility of toner scattering inside the device can be reduced.

[0298] In this example, seals 71, 72, and 73 are separated by moving the lifting duct 69 and the developing unit 24 away from the target member, but the configuration is not limited to this. Even if seals 71, 72, and 73 are not separated by moving the lifting duct 69 and the developing unit 24 away from the target member, the seal of the gap can be released by reducing the pressure applied.

[0299] Furthermore, the sealing members, seals 71, 72, and 73, here use foamed sealing material made of rubber sponge. In terms of the dimensions of the seals, the thickness of the seals is made larger than the width of the gap mentioned above, and the difference is used as the amount of compression of the seals, thereby compressing the air bubbles inside and increasing the sealing force.

[0300] The sealing material used for sealing is not limited to foamed sealant; for example, a rubber sheet material such as a urethane sheet (sheet material) may also be used. In this case, a sheet longer than the width of the gap mentioned above is used, and the sealing is achieved by aligning the edge of the sheet with the object it is in contact with. To increase the sealing force, unlike with foamed sealant, the length of the sheet and the contact angle can be increased to raise the contact force with the object.

[0301] Regardless of whether the seal is made of rubber sponge or rubber sheet material, it must be attached using adhesive means such as double-sided tape. Since the adhesive area is small, equal to or less than the width of the seal, if the seal is subjected to stress such as bending or shifting in its short direction, the adhesive may peel off, potentially leading to the seal lifting, detaching, or falling off. Therefore, when attaching and applying the seal, the configuration should be such that the stress it receives in its short direction is minimized.

[0302] Furthermore, while bellows-shaped rubber materials could also be considered as general sealing materials, they require a certain amount of space for expansion and contraction, and their ease of assembly is not ideal. Therefore, they are not intended for use in this embodiment.

[0303] (Angle of sealing member) Here, we will explain the sealing members, seals 71 and 72, in more detail.

[0304] The sealing members, seals 71 and 72, reduce the risk of toner contamination in the exposure cooling airflow and the developer cooling airflow, thereby reducing toner scattering inside the device. For this reason, the sealing members must be constructed in a way that prevents them from peeling, detaching, or falling off.

[0305] Here, the direction of movement of the exposure head 4 from the retracted position shown in Figure 25 to the exposure position shown in Figure 24 is indicated by arrow G in Figure 23. Seals 71 and 72 are attached to the lifting duct 69 at predetermined angles θ1 and θ2, respectively, with respect to the direction of movement of the exposure head 4, which is arrow G.

[0306] Specifically, the seal 71 is provided on the second inclined surface 69R1 of the right wall 69R of the lifting duct 69, which is the side wall on the drum unit 23 side. The second inclined surface 69R1 of the right wall 69R of the duct is inclined at a predetermined angle θ1 with respect to the direction of arrow G. Here, a configuration in which the lifting duct 69 is provided with an inclined surface inclined at an angle θ1 is illustrated, but a configuration in which the contact surface of the seal 71 is inclined at an angle θ1 may also be used.

[0307] The seal 72 is provided on the first inclined surface 69L1 of the left wall 69L of the lifting duct 69, which is the side wall on the developing unit 24 side. The first inclined surface 69L1 of the left wall 69L of the duct is inclined at a predetermined angle θ2 with respect to the direction of arrow G. Here, a configuration in which the lifting duct 69 is provided with an inclined surface inclined at an angle θ2 is illustrated, but a configuration in which the contact surface of the seal 72 is inclined at an angle θ2 may also be used.

[0308] The sealing force of the gap by seals 71 and 72 is determined by the amount of compression of the seals, as described above, in the case of rubber sponge material. Therefore, if a predetermined amount of seal compression is secured at the exposure position shown in Figure 24, where the exposure head 4 is close to the photosensitive drum 2, the angle at which seals 71 and 72 are attached does not affect the sealing of the gap between the lifting duct 69 and the cartridge tray 30. Also, in Figure 22, seals 71 and 72 are mainly subjected to a load that compresses their thickness, and this load does not cause the seals to peel, detach, or fall off.

[0309] Next, the load on seals 71 and 72 due to the movement of the exposure head 4 will be explained using Figure 23.

[0310] The cross-sectional position shown in Figure 23 is the same as in Figure 22, corresponding to the position indicated by arrow XX in Figure 20, and is a cross-sectional view of the range La shown in Figure 20. However, while in Figure 22 the exposure head 4 is in an exposure position close to the photosensitive drum 2, in Figure 23 the exposure head 4 has moved to a retracted position away from the photosensitive drum 2. This corresponds to the position shown in Figure 25, where the exposure head 4 has been retracted from the exposure position to the retracted position.

[0311] In Figure 23, seals 71 and 72, including seal 70, are separated from the member they are in contact with, and the seal of the gap is released. In other words, when the exposure head 4 is retracted from the exposure position and the developing unit 24 is retracted from the developing position, the seals 71, 72, and 73 release the seal of the gap.

[0312] This is because sealing the gap is not necessary during the movement of the exposure head 4, but only when the exposure head 4 is positioned relative to the photosensitive drum 2 at the exposure position shown in Figure 22 and the image formation process begins.

[0313] In the state shown in Figure 23 (retracted position), no load is applied to seals 71 and 72. Therefore, seals 71 and 72 will not peel, detach, or fall off.

[0314] Regarding the load on seals 71 and 72 during the movement of the exposure head 4, consider moving seals 71 and 72 in the direction of arrow G from the state shown in Figure 23.

[0315] In the case of the seal 71, until the lifting duct 69 reaches the state shown in Figure 22 (exposure position), the seal 71 provided on the second inclined surface 69R1 of the lifting duct 69 does not come into contact with the opposing portion 302d of the first drum guide portion 302a, and is therefore not subjected to any load.

[0316] In the case of seal 72, the corners of seal 72 come into contact with the cartridge tray 30 after movement begins, but only an oblique load is applied to the surface of seal 72, and the risk of seal 72 peeling or detaching is small. This oblique load on seal 72 is determined by the application angle θ2 of seal 72, and the larger the angle θ2, the smaller the component force that induces peeling or detachment of seal 72. For example, if the angle θ2 is 90°, that is, if it is applied perpendicular to the direction of movement of the exposure head 4 (direction of arrow G), seal 72 will not be subjected to any load during the movement of the exposure head 4. Therefore, similar to the retracted position shown in Figure 34, peeling or detachment of seal 72 will not occur.

[0317] However, increasing the angles θ1 and θ2 increases the area required for the movement of seals 71 and 72 due to the movement of the exposure head 4, making it difficult to house the movement mechanism of the exposure head 4 compactly. Therefore, it is necessary to set the angles θ1 and θ2 within a predetermined range. In this embodiment, the appropriate range for angles θ1 and θ2 is from 20° to 90° (20°≦θ1≦90°, 20°≦θ2≦90°).

[0318] Therefore, the load on seals 71 and 72 due to the movement of the exposure head 4 can be minimized. As a result, seals 71 and 72 will not peel, detach, or fall off during the movement of the exposure head 4. In addition, friction between seals 71 and 72 does not create resistance to the movement of the exposure head 4 itself. This contributes to the stability of the exposure head's movement.

[0319] By configuring it in this way, it is possible to provide a cooling means for the exposure head 4 that is compatible with the movement mechanism of the exposure head 4 and has sealing properties that reduce toner scattering inside the device.

[0320] (Cooling control of the exposure head and the developing unit) Next, we will explain the cooling control of the exposure head 4 and the cooling control of the development unit 24.

[0321] The cooling of the exposure head 4 is controlled by controlling the intake fan 62 and exhaust fan 63 in the duct unit 60 based on detection signals from temperature sensors (not shown) placed on each color substrate 50. As a result, the intake fan 62 and exhaust fan 63 of the duct unit 60 do not rotate constantly, but rather start rotating when the temperature detected by the temperature sensors reaches a predetermined threshold. In this way, the operation of the exposure cooling airflow by the intake fan 62 and exhaust fan 63 is minimized, and the airflow is also kept to the minimum necessary, thereby reducing toner scattering inside the image forming apparatus 100 from a control standpoint.

[0322] On the other hand, the cooling control of the developing unit 24 is performed by controlling a fan 40 located on the front side of the device based on a detection signal from an in-machine temperature sensor (not shown) located inside the image forming apparatus 100, separate from the temperature detection sensor. In other words, the cooling control of the developing unit is performed by controlling the fan 40, and is controlled differently from the intake fan 62 and exhaust fan 63 in the duct unit 60. This ensures that the developing unit 24 is cooled to the optimal and minimum extent in response to its elevated temperature.

[0323] The heating conditions for the developing unit 24 and the exposure head 4 are different. Therefore, as mentioned above, the cooling control for the exposure head 4 and the cooling control for the developing unit 24 are controlled separately. This allows the fan operation and fan airflow to be kept to the minimum necessary for each cooling control, further reducing toner scattering inside the image forming apparatus 100.

[0324] By configuring it in this way, it is possible to provide a cooling means for the exposure head 4 that prevents toner from scattering inside the image forming apparatus 100, thereby reducing the possibility of image defects and toner adhering to the user.

[0325] Figure 26 is a cross-sectional view of the EE shown by the arrow in Figure 37. Note that Figure 26 shows the FFC 58, drum unit 23, and developing unit 24, which were not shown in Figure 37.

[0326] In the duct unit 60, the intake fan 62, positioned towards the front of the image forming apparatus 100, functions as an intake fan that draws in air from outside the apparatus. Therefore, when the intake fan 62 rotates, air is drawn into the intake duct 205 from outside the apparatus through the intake port 203. The air drawn in from outside the apparatus flows along the intake duct 205 from left to right of the image forming apparatus 100, as shown by the dotted line (airflow 310 inside the duct) in Figure 37. The air flowing from left to right within the intake duct 205 branches out from the left side of the apparatus through the third openings 201 for each color, provided on the upper surface of the intake duct 205, in the order of openings 201Y, 201M, 201C, and 201K, as shown in Figure 37.

[0327] Air sent from the third opening 201 of the duct unit 60 is sent upward through the first opening 73, which is in communication with the opening 201, between the cartridge tray 30 and the lifting duct 69. The air sent upward through the space between the cartridge tray 30 and the lifting duct 69 is blown onto the back surface of the substrate 50 of the exposure head 4 through the opening 69a of the lifting duct 69 and the opening 55a of the exposure head 4, which are connected vertically.

[0328] Here, the first opening 73 is an opening that is located towards the front of the device and communicates with the third opening 201 of the duct unit 60, within the opening 64 formed by the cartridge tray 30 and the lifting duct 69.

[0329] In other words, the first opening 73 is located on one end of the substrate 50, rather than at the center in the longitudinal direction, and faces the third opening 201 when the duct unit 60 is mounted.

[0330] At the front of the image forming apparatus 100, the air blown onto the back surface of the substrate 50 of the exposure head 4 attempts to flow along the longitudinal direction of the substrate 50 through the space between the left wall 55L and the right wall 55R of the housing support member 55. At this time, in the exposure head 4, the airflow toward the connector area is blocked by the shielding wall 76. Therefore, the airflow blown onto the back surface of the substrate 50 flows through the duct area from one side (front) to the other side (rear).

[0331] The exposure head 4 and the duct unit 60 are connected by a duct (cooling duct 75) formed by the cartridge tray 30 and the lifting duct 69. As a result, the airflow blown onto the back surface of the substrate 50 is guided through this duct (for example, from the front to the back in the longitudinal direction of the substrate), and the substrate 50 is cooled in the process.

[0332] In addition to the aforementioned intake, the exhaust fan 63 located towards the rear of the image forming apparatus 100 in the duct unit 60 functions as an exhaust fan that exhausts air from inside the duct unit 60 to the outside of the apparatus. Therefore, when the exhaust fan 63 rotates, air is drawn in through the fourth openings 202 (Y, M, C, K) for each color, which are provided on the upper surface of the exhaust duct 206. The fourth openings 202 are in communication with the second openings 74. Therefore, air from inside the duct (cooling duct 75) formed by the cartridge tray 30 and the lifting duct 69 is drawn in through the second openings 74, which are in vertical communication with the fourth openings 202 for each color, which are provided on the upper surface of the exhaust duct 206.

[0333] Here, the second opening 74 is an opening that is located towards the rear of the device, within the opening 64 formed by the cartridge tray 30 and the lifting duct 69, and communicates with the fourth opening of the duct unit 60, which is opening 202.

[0334] In other words, the second opening 74 is located on the other end of the substrate 50, rather than at the center in the longitudinal direction, and faces the fourth opening 202 when the duct unit 60 is mounted.

[0335] Air is drawn in from the fourth opening 202 of the duct unit 60 through the second opening 74. As a result, an exposure cooling airflow, which is the airflow shown by the dotted line (airflow inside the duct 311) in Figure 26, is generated in the duct formed by the cartridge tray 30 and the lifting duct 69, and in the exposure head 4 which is integrally supported by the lifting duct 69, and the substrate 50 on which the LED 51 is mounted is cooled.

[0336] In the duct unit 60, the air taken in from the fourth opening 202 of the exhaust duct 206 flows from the right side of the device towards the left side, as shown by the dotted line (duct airflow 312) in Figure 39, by sequentially converging through openings 202K, 202C, 202M, and 202Y. Finally, the air taken into the exhaust duct 206 is exhausted to the outside of the device through the exhaust port 204.

[0337] Furthermore, in the duct unit 60, the cross-sectional area of ​​the intake duct 205 is made smaller compared to the cross-sectional area of ​​the exhaust duct 206. As a result, the airflow rate in the exhaust duct 206 is greater than the airflow rate in the intake duct 205. This ensures that the exposure cooling airflow can be reliably exhausted from the exhaust port 204 without leaking out of the cooling duct 75 formed between the cartridge tray 30 and the lifting duct 69. In addition, the above configuration prevents heated air from raising the temperature of the developing unit 24, etc., and suppresses toner scattering.

[0338] In this embodiment, the balance of intake and exhaust airflow was adjusted by the cross-sectional area of ​​the intake duct 205 and the exhaust duct 206, but it may also be adjusted by reducing the airflow of the intake fan 62 relative to that of the exhaust fan 63.

[0339] (Positioning of the exposure head) Next, the positioning of the exposure head 4 will be explained with reference to Figures 26, 43, and 44-49.

[0340] (Positioning pins for the exposure head) First, let's explain the positioning pins 45F and 45B of the exposure head 4.

[0341] The housing 54 of the exposure head 4 is provided with positioning pins 45F and 45B, which are positioning axes. Both positioning pins 45F and 45B are examples of metal pins. The housing 54 is made of a conductive material, and the positioning pins are also made of a conductive material. Positioning pins 45F and 45B are fixed to both ends of the housing 54 in the longitudinal direction. Positioning pin 45F is fixed to the housing 54 on one side (front side) of the lens array 52 in the axial direction of the photosensitive drum 2, and protrudes from both sides of the housing 54 in the optical axis direction of the lens array 52. ​​Positioning pin 45B is fixed to the housing 54 on the other side (rear side) of the lens array 52 in the axial direction of the photosensitive drum 2, and protrudes from both sides of the housing 54 in the optical axis direction of the lens array 52.

[0342] Positioning pin 45F, 45B In order to ensure high precision in the distance between the surface of the photosensitive drum 2 and the light-emitting surface of the lens array 52 of the exposure head 4, the position of the positioning surface at the tip of the shaft is adjusted with reference to the housing 54 and crimped to the housing 54. Note that the fixing of the positioning pins 45F and 45B to the housing 54 is not limited to this, and for example, metal positioning pins 45F and 45B may be fixed to the metal housing 54 by welding. Thus, in this embodiment, the positioning pins 45F and 45B are integrated with the housing 54.

[0343] Then, the positioning pins 45F and 45B of the exposure head 4 abut against the drum bearing 26 of the drum unit 23 in the direction of movement of the lifting duct 69, thereby creating a gap between the lens array 52 and the photosensitive drum 2. In this way, the distance (gap) between the exposure head 4 and the photosensitive drum 2 is determined in a direction perpendicular to the axial direction of the photosensitive drum 2, and the position of the exposure head 4 relative to the photosensitive drum 2 is determined.

[0344] Furthermore, the exposure head 4 is fixed not only in distance from the photosensitive drum 2 but also in angle by positioning pins 45F and 45B. In the image forming apparatus 100 shown in Figure 2, the exposure head 4 is positioned to face the center of the photosensitive drum 2. This arrangement is adopted because, due to the mechanism of the LED (light-emitting element) 51 of the exposure head 4, it is not necessary to consider the effect of specular reflection on the surface of the photosensitive drum 2.

[0345] Figure 43 is a cross-sectional view showing the relationship between three components: the photosensitive drum 2, positioning pins 45F and 45B (part of the positioning end), and the rotating arm 65. Figure 43 is a visualization of only the surrounding components of the three components in the YY cross-sectional view of Figure 24. The cross-sectional position has been moved to the center of the positioning pins 45F and 45B.

[0346] Figure 44 is a perspective view taken from the front of the photosensitive drum 2, cut in a direction perpendicular to the axial direction of the photosensitive drum 2, at the center positions of the positioning pins 45F and 45B. Figure 45 is a perspective view taken from the rear of the photosensitive drum 2, cut in a direction perpendicular to the axial direction of the photosensitive drum 2, at the center positions of the positioning pins 45F and 45B.

[0347] In Figures 43 and 44, the optical axis direction of the exposure head 4 is positioned by the positioning pin 45F (45B) on the front side of the exposure head 4 and the drum bearing 26 on the front side of the photosensitive drum 2 abutting against the end face of the positioning pin 45F (45B).

[0348] Each drum bearing 26 has a recessed engaging portion 26F, 26B integrally formed at a position opposite to each positioning pin 45F, 45B, so that it can engage with the tip of each positioning pin 45F, 45B. By precisely machining the diameter of the tip of the positioning pin 45 and the width of the recessed portion of the drum bearing 26, precise positioning is achieved in a direction perpendicular to the optical axis direction of the exposure head 4 and perpendicular to the axial direction of the photosensitive drum 2. In addition, a slope is formed at the entrance to the engaging portion 26F, 26B of the drum bearing 26 to prevent the positioning pins 45F, 45B from riding up onto the edge of the recessed portion.

[0349] As shown in Figure 26, the positioning pins 45F and 45B and the drum bearing 26 are not in contact in the axial direction of the photosensitive drum 2, and are positioned by the positioning member 250, which will be described later.

[0350] Here, the drum bearing 26 is a bearing member in the drum unit 23 that pivotally supports the front and rear ends (both ends) of the photosensitive drum 2. By increasing the dimensional accuracy at the engagement point of this drum bearing 26, the photosensitive drum 2 is pivotally supported by the drum bearing 26 without any gaps. In other words, high-precision positioning on the drum bearing 26 can be considered to be high-precision positioning on the photosensitive drum 2. The photosensitive drum 2 is rotated in accordance with the image forming process. Therefore, the positioning pin 45 of the exposure head 4 is positioned relative to the drum bearing 26.

[0351] Figures 43 and 44 show cross-sections of the front drum bearing 26 of the image forming apparatus, but the rear drum bearing 26 has a similar shape. As shown in Figure 45, the positioning pins 45B of the exposure head 4 are also positioned with high precision relative to the rear drum bearing 26 of the image forming apparatus. Therefore, the exposure head 4 is positioned with high precision at both ends in the axial direction of the photosensitive drum 2.

[0352] Furthermore, as shown in Figure 43, the pressing position where the engaging boss 66 of the rotating arm 65 presses against the lifting duct 69, the contact positions between the positioning pins 45F, 45B and the engaging portions 26F, 26B of the drum bearing 26, and the center position of the photosensitive drum 2 are arranged in a nearly straight line, as indicated by the dashed line.

[0353] This arrangement ensures that the exposure head 4 is pressed toward the center of the photosensitive drum 2, thus preventing any unnecessary rotational moment from being applied to the lifting duct 69. This means that there is no component in the pressing force that would cause the exposure head 4 to tilt relative to the photosensitive drum 2, leading to improved positioning accuracy in terms of distance and angle, as well as stability during repeated attachment and detachment operations.

[0354] Furthermore, as shown in Figures 44 and 45, the positioning pins 45F and 45B are auxiliaryly fitted to the auxiliary fitting portions 30h and 30i of the cartridge tray 30 at their lower end circumferential surfaces in directions perpendicular to the optical axis direction of the exposure head 4 and perpendicular to the axial direction of the photosensitive drum 2. This ensures stable positioning accuracy in terms of distance and angle, as well as the ability to repeatedly attach and detach parts, even when slight rotational moments occur due to the weight of the parts, surface properties, dimensional errors, etc.

[0355] (Positioning member for exposure head) Next, the positioning of the exposure head 4 in the axial direction of the photosensitive drum 2 by the positioning member 250 will be explained in detail with reference to Figures 46 to 48.

[0356] Figure 46 is a perspective view after the positioning member 250 has been installed, and Figure 47 is a perspective view before the positioning member has been installed. Figure 48 is a perspective view showing the shape of the positioning member 250.

[0357] As shown in Figure 46, a positioning member 250 is attached to the front of the exposure head 4. As shown in Figure 47, a biasing portion 30d, a round hole portion 30e, a square hole portion 30f, and a claw engagement portion 30g are provided on the front of the cartridge tray 30.

[0358] Furthermore, as shown in Figure 48, the lower surface of the positioning member 250 is provided with a third engaging portion, which consists of a restricting portion 250a, a biasing portion 250b, a cross projection 250c, an I-shaped projection 250d, and a claw portion 250e.

[0359] The outer diameter of the cross-shaped projection 250c is approximately equal to the inner diameter of the round hole 30e, and the length of the I-shaped projection 250d in the left-right direction is approximately equal to the length of the square hole 30f in the left-right direction. The position of the positioning member 250 in the front-rear and left-right directions is determined by the fitting of each projection 250c, 250d with the holes 30e, 30f.

[0360] Furthermore, the claw portion 250e has a return shape, and the vertical position of the positioning member 250 is determined by the return shape catching on the claw engagement portion 30g.

[0361] The third engaging portion, the regulating portion 250a, is a positioning pin 45F A first contact surface 250a1 that abuts against one side in the axial direction of the and a positioning pin 45F The regulating portion 250a has a second contact surface 250a2 that abuts against the other side in the axial direction of the regulating portion 250a. The first contact surface 250a1 and the second contact surface 250a2 face each other in the axial direction. The regulating portion 250a has a concave shape with an opening on the right side in the left-right direction, and the width of the notch in the front-rear direction of the concave shape and the outer diameter of the positioning pin 45F are configured to be approximately equal. Here, the left-right direction is a second direction perpendicular to the direction of movement of the lifting duct 69 (first direction) and the axial direction of the photosensitive drum 2. The exposure head 4 in the axial direction of the photosensitive drum 2 is positioned relative to the positioning member 250 by fitting the regulating portion 250a, which is the third engaging portion, with the positioning pin 45F.

[0362] In this way, the positioning member 250, which is attached after the exposure head 4 is mounted, allows for precise positioning of the axial position of the photosensitive drum 2 of the exposure head 4.

[0363] Here, all parts, including the positioning member 250, the cartridge tray 30, and the positioning pin 45F, will have some play between them due to manufacturing variations. If the play is large, there is a risk that the position of the exposure head 4 will vary due to repeated attachment and detachment of the exposure head 4.

[0364] In this embodiment, to address the aforementioned problem, play is eliminated by the biasing portion 250b and the biasing portion 30d. The biasing portion 250b extends to the right in the left-right direction from the positioning member 250, and the thickness in the axial direction of the photosensitive drum 2 is thin, making it a shape that is easily elastically deformed in the axial direction of the photosensitive drum 2. On the other hand, the biasing portion 30d has a shape that protrudes from the upper surface of the cartridge tray 30, and is configured to have a rigid shape that does not deform in the axial direction of the photosensitive drum 2. When the positioning member 250 is mounted on the cartridge tray 30, the tip of the biasing portion 250b is configured to interfere with (contact) the biasing portion 30d. The front surface of the tip of the biasing portion 250b and the back surface of the biasing portion 30d come into contact, and the biasing portion 250b elastically deforms in the direction of the back, and the positioning member 250 is biased in the direction of the back, that is, from one side to the other in the axial direction of the photosensitive drum 2, by the reaction force.

[0365] In this way, by configuring the positioning member 250 to be biased in the axial direction of the photosensitive drum 2, it is possible to achieve highly accurate positioning of the exposure head 4, which is less susceptible to the effects of repeated attachment and detachment operations of the exposure head 4, and to achieve even more precise positioning.

[0366] (Exposure head replacement / removal configuration) The replacement and attachment / detachment configuration of the exposure head 4 will be explained in detail using Figures 33 and 49 to 65. Figure 33 is a cross-sectional view taken along the XX arrow in Figure 20, similar to Figure 22. Figure 33 is a cross-sectional view of the exposure head 4, the lifting duct 69, and the cartridge tray 30 from the front, without showing the drum unit 23 or the developing unit 24.

[0367] As already explained, the exposure head 4 is configured to be detachable from the image forming apparatus 100. The procedure for attaching the exposure head 4 will be explained in detail with reference to Figures 49 to 65.

[0368] Figure 49 is a right-side perspective view showing the state immediately before the exposure head 4 is attached to the lifting duct 69, Figure 50 is a front cross-sectional view, and Figure 51 is a left-side perspective view.

[0369] In the state shown in Figures 49 and 51, the drum unit 23, the developing unit 24, and the positioning member 250 have been removed from the image forming apparatus. The exposure head 4 is replaced and attached / detached with the drum unit 23, the developing unit 24, and the positioning member 250 removed. Also, with the photosensitive drum 2 removed, the exposure head 4 is operated manually. by The system is configured to allow movement from the retracted position to the exposure position. Therefore, when replacing or attaching / detaching the exposure head 4, the process is carried out with the exposure head 4 manually moved to the exposure position. At this time, as shown in Figure 50, the FFC 58 connected to the main body of the device is pre-connected to the FFC connector 57 of the exposure head 4.

[0370] As described above, the housing support member 55 of the exposure head 4 is provided with engaging claws 55b and 55c for engaging with the lifting duct 69. On the other hand, the lifting duct 69 is provided with engaging holes 69b and 69c on the upper surface portion 69U facing the exposure head 4 for engaging with the engaging claws 55b and 55c. Based on this configuration, the procedure for engaging the engaging claws 55b and 55c of the exposure head with the engaging holes 69b and 69c of the lifting duct to form a single unit is as follows.

[0371] First, as shown in Figures 49 and 51, by moving the exposure head 4 in the direction of arrow D relative to the lifting duct 69, the engaging claws 55b and 55c of the exposure head 4 are dropped into the engaging holes 69b and 69c of the lifting duct 69, respectively. That is, the engaging claws 55b and 55c of the exposure head are engaged with the engaging holes 69b and 69c in a protruding direction. At the same time, the lower end of the positioning pin 45F of the exposure head 4 is dropped into the auxiliary fitting portion 30h of the cartridge tray 30 with a gap. At this time, the excess length of the FFC 58 connected to the substrate of the main body of the device and the substrate of the exposure head 4 protrudes from the harness opening 252, which will be described later. This state is shown in Figures 52 to 56.

[0372] Figure 52 is a right-side perspective view with the exposure head 4 placed in the lifting duct 69, Figure 53 is a front cross-sectional view, and Figure 54 is a left-side perspective view. Figure 55 is a cross-sectional view with the exposure head 4 placed in the lifting duct 69. Figure 56 is a perspective view of the vicinity of the conductive member with the exposure head 4 placed in the lifting duct 69.

[0373] Next, as shown in Figure 52, the exposure head 4 is slid in the direction of arrow B relative to the lifting duct 69, and the engaging claws 55b and 55c are engaged with the engaging holes 69b and 69c in an extending direction perpendicular to the protruding direction. The state at this time is shown in Figures 57 to 61.

[0374] Figure 57 is a right-side perspective view of the exposure head 4 mounted on the lifting duct 69, and Figure 58 is a left-side perspective view. Figure 59 is a cross-sectional view taken along the WW arrow in Figure 33, showing the exposure head 4 mounted on the lifting duct 69. Figure 60 is an enlarged cross-sectional view of the engagement portion shown in Figure 59. Figure 61 is a perspective view of the vicinity of the conductive member with the exposure head 4 mounted on the lifting duct 69. Figure 62 is a right-side cross-sectional view showing the harness opening. Figure 63 is a right-side perspective view of the FFC after excess length processing. Figure 64 is a front cross-sectional view of the FFC after excess length processing. Figure 65 is a front cross-sectional view showing the state of the FFC in the retracted position.

[0375] The engaging claws 55b and 55c of the exposure head 4 are formed to protrude toward the lifting duct 69 and have a roughly L-shape that extends in the direction of arrow B, which is the sliding direction of the exposure head 4. Therefore, when the exposure head 4 slides in the direction of arrow B, the tips of the roughly L-shaped claws 55b and 55c engage with the edges of the engaging holes 69b and 69c. Through this engagement, the exposure head 4 is mounted on the lifting duct 69 and becomes integrated with the lifting duct 69 at the positions shown in Figures 57 to 59.

[0376] In this manner, after stabilizing the position of the exposure head 4 with its engaging claws 55b and 55c passing through the engaging holes 69b and 69c of the lifting duct 69, the exposure head 4 is slid to complete the mounting. This makes it possible to achieve easy mounting of the exposure head 4 with an inexpensive configuration.

[0377] (Relationship between engaging claw and engaging hole) Here, with reference to Figure 60, the relationship between the engagement claws of the exposure head 4 and the engagement holes of the lifting duct 69 will be explained in more detail. Here, the relationship between the engagement claws 55b of the exposure head 4 and the engagement holes 69b of the lifting duct 69 will be explained, but the relationship between the engagement claws 55c of the exposure head 4 and the engagement holes 69c of the lifting duct 69 is similar.

[0378] As shown in Figure 60, the engaging claw 55b is elastic, and a recess 55f is provided at the extended tip of the engaging claw 55b. The engaging hole corresponds to the recess 55f. 69b The edge is provided with a protrusion 69f that engages with the recess 55f. Engagement hole 69b The protrusion 69f provided on the edge is positioned at a location corresponding to the recess 55f provided on the tip of the engaging claw 55b when the exposure head 4 completes its sliding movement relative to the lifting duct 69, i.e., when it is fully mounted.

[0379] Just before the exposure head 4 completes its sliding motion in the direction of arrow K, the tip of the engaging claw 55b interferes with the protrusion 69f, causing the engaging claw 55b to elastically deform, and the sliding force of the exposure head 4 increases once compared to the force immediately before the interference. Then, the recess 55f of the engaging claw 55b immediately reaches the protrusion 69f, and the recess 55f and the protrusion 69f engage, causing the sliding force of the exposure head 4 to decrease. In other words, when the exposure head 4 is moved in the extension direction relative to the lifting duct 69, the elastic deformation of the engaging claw 55b before the recess 55f and the protrusion 69f engage changes the force required to move the exposure head 4 in the extension direction. This rapid increase or decrease in the sliding force of the exposure head 4 provides a click sensation that indicates the completion of the sliding operation of the exposure head 4.

[0380] In this way, the elastic deformation of the engaging claw 55b until the recess 55f of the engaging claw 55b and the protrusion 69f of the engaging hole 69b engage changes the sliding force of the exposure head 4, thereby clearly indicating that the exposure head 4 has been mounted.

[0381] As mentioned above, as shown in Figures 44 and 45, the positioning pins 45F and 45B of the exposure head 4 are auxiliaryly fitted to the auxiliary fitting portions 30h and 30i of the cartridge tray 30 at their lower end circumferential surfaces. This fitting is performed simultaneously by the sliding operation of the exposure head 4 in the direction of arrow B, as shown in Figures 54 and 58.

[0382] Furthermore, in this embodiment, the ground connection between the exposure head 4 housing 54 and the image forming apparatus 100 is also performed simultaneously by the sliding operation of the exposure head 4 in the direction of arrow B described above. The exposure head 4 housing 54 and the positioning pins 45F and 45B are crimped and fixed together, and electrical conductivity is ensured. The ground connection with the image forming apparatus 100 is made by the circumferential surface of the positioning pin 45F of the exposure head 4 contacting a conductive member 251 provided on the cartridge tray 30 on the apparatus side, as shown in Figures 56 and 61. The conductive member is electrically conductive. Specifically, the conductive member 251 is made of a thin metallic plate. Therefore, it is configured to obtain sufficient contact pressure by contacting and deforming due to the sliding operation of the exposure head 4. The conductive member 251 is electrically connected to the frame sheet metal of the image forming apparatus 100 after passing through a circuit board on which a harness (not shown), a resistor element for noise reduction, and a capacitor are mounted.

[0383] In this way, the positioning pin 45F of the exposure head 4 can be electrically connected to the conductive member 251 by sliding, thereby connecting the exposure head 4 to ground. This makes it possible to easily connect the exposure head 4 to ground or the like to suppress the generation of radiated noise such as electromagnetic waves. In other words, stable grounding characteristics can be obtained simply by sliding the exposure head 4 to the lifting duct 69.

[0384] (FFC excess length processing) Here, we will explain the excess length processing for FFC58.

[0385] Figure 62 is a right-side cross-sectional view showing the harness opening. The harness opening 252 is composed of a first opening forming portion 55g formed in the housing support member 55 that constitutes the exposure head 4, a second opening forming portion 69g formed in the lifting duct 69 which is left on the main body side of the image forming apparatus 100 when replaced, and a second opening forming portion 30c formed in the cartridge tray 30.

[0386] In other words, the harness opening 252 is formed by surrounding a first opening forming portion 55g provided near the connector 57 of the exposure head 4, and a second opening forming portion 69g, 30c provided near the first opening forming portion 55g and on the main body of the device. Here, an example is shown in which the second opening forming portion constituting the harness opening 253 is provided on the lifting duct 69 and the cartridge tray 30, respectively.

[0387] In this embodiment, the harness opening 252 is formed on the drum unit 23 side, which is the photoreceptor unit. This is because, on the developing unit 24 side, a part of the duct that serves as a flow path for airflow (developing cooling airflow) to cool the developing unit 24 is provided by the developing unit 24 and the developing support member 301. For this reason, the harness opening 252 is provided on the drum unit 23 side so as not to affect the developing cooling airflow.

[0388] In this way, by providing the harness opening 252 on the drum unit 23 side located near the exposure head 4, it is possible to prevent it from affecting the airflow along the developing unit 24.

[0389] As shown in Figures 52, 53, and 57, when the exposure head 4 is lowered into the lifting duct 69 and when it is mounted, the excess length of the FFC 58 protrudes from the harness opening 252 toward the drum support member 302, interfering with the insertion and removal trajectory of the drum unit 23.

[0390] This excess length of FFC58 is the slack (excess length) of FFC58 formed between the exposure head 4 and the lifting duct 69 when the exposure head 4 is lowered into the lifting duct and when it is mounted.

[0391] In this way, the exposure head 4 can be mounted on the image forming apparatus with the excess length of the FFC 58 extended from the harness opening 252, which consists of the first opening forming section 55g and the second opening forming section 69g and 30c.

[0392] After the exposure head 4 is attached to the lifting duct 69, the excess length of the FFC 58 is processed. The FFC 58 has a bent portion 58a that is pre-folded in one or more places. The FFC 58 is folded along the bent portion 58a, and the excess length is stored through the harness opening 252.

[0393] Figures 63 and 64 show the state after the excess length of the FFC58 has been processed. Figure 63 is a right side perspective view of the FFC58 after the excess length has been processed. Figure 64 is a front cross-sectional view of the FFC58 after the excess length has been processed. Figure 64 is a front cross-sectional view of the position of the FFC58 when the exposure head 4 is in close proximity to the photosensitive drum 2 due to the movement mechanism of the exposure head 4 (hereinafter referred to as the exposure head proximity state). By bending the FFC58 back and forth multiple times in the direction of the optical axis and storing it, the excess length of the FFC58 can be stored in a space-saving manner, especially on the upper side near the FFC connector 57.

[0394] Furthermore, as shown in Figure 64, the length of the FFC 58 from the connection end to the FFC connector 57 to the first bent portion 58a as viewed from that end is longer than the distance from the harness opening 252 to the FFC connector 57. This prevents the bent portion 58a of the FFC 58 from overlapping the harness opening 252, thus preventing the FFC 58 from protruding from the harness opening 252.

[0395] Figure 65 is a front cross-sectional view of the position of the FFC 58 when the exposure head 4 is retracted from the photosensitive drum 2 by the exposure head 4's movement mechanism (hereinafter referred to as the exposure head retracted state). It can be seen that the opening area of ​​the harness opening 252 is smaller in the exposure head retracted state shown in Figure 65 compared to the exposure head close state shown in Figure 64. This prevents the FFC 58 from protruding from the harness opening 252 even when the exposure head 4 moves between the exposure head close state and the retracted state multiple times by the movement mechanism.

[0396] Finally, as shown in Figure 47, the positioning member 250 is assembled to the cartridge tray 30, thereby completing the installation of the exposure head 4 as shown in Figure 46.

[0397] Next, the procedure for removing the exposure head 4 will be explained using Figures 49 to 65.

[0398] When removing the exposure head 4, the removal is also carried out in the same way as when installing it (Figures 52 and 54), with the exposure head in close proximity, and is basically done in the reverse order of installation.

[0399] First, from the state shown in Figure 46, the claw portion 250e of the positioning member 250 is deformed to release the engagement from the claw engagement portion 30g of the cartridge tray 30, and the positioning member 250 is removed from the cartridge tray 30 as shown in Figure 25.

[0400] In this case, unlike when installing, when removing the exposure head 4, there is no need to handle the excess length of the FFC58, for example, by pulling the FFC58 out of the harness opening 252.

[0401] Next, the exposure head 4 is slid in the opposite direction to the direction of arrow B shown in Figure 52, releasing the engagement between the engaging claws 55b and 55c and the engaging holes 69b and 69c, making it possible to separate it from the lifting duct 69.

[0402] Finally, the exposure head 4 is lifted in the opposite direction to arrow D shown in Figure 49, and the engaging claws 55b and 55c are pulled out from the engaging holes 69b and 69c. As the exposure head 4 is lifted, the folded and stored FFC 58 extends, making it possible to pull the exposure head 4 out of the image forming apparatus 100. In this state, the FFC 58 is pulled out from the FFC connector 57, completing the removal of the exposure head 4.

[0403] [Other examples] The configuration according to the present invention is not limited to the embodiments described above.

[0404] In the above-described embodiment, a tandem-intermediate transfer type four-color full-color printer was used as an example. However, for example, a direct transfer method may be used in which the toner image is transferred from the photosensitive drum 2 to the recording paper P without using the intermediate transfer belt 9. Furthermore, a five-color or more full-color printer using one-color monocolor or spot color toner may also be used. In that case, a configuration equipped with exposure heads 4 corresponding to the number of colors may be used.

[0405] In the embodiments described above, an elastic material such as a sponge or rubber made of urethane or silicone was used as the sealing member 207. However, a resin sheet such as PET, modified PPE, or PE may also be used and elastically deformed to seal the gaps in each opening.

[0406] Furthermore, although the sealing member 207 is configured to be placed in the duct unit 60, it may also be placed in the cartridge tray 30 or the lifting duct 69, or a configuration in which it is placed in multiple parts may be selected.

[0407] Furthermore, although the third opening 201 and fourth opening 202 of the duct unit 60 are connected to an opening 64 (first opening 73 and second opening 74) formed by the cartridge tray 30 and the lifting duct 69, the configuration is not limited to this. For example, the opening 64 may be eliminated, and a first opening 73 and a second opening 74 may be provided in the lifting duct 69, respectively, so that the third opening 201 and fourth opening 202 of the duct unit 60 are directly connected to the first opening 73 and the second opening 74, respectively.

[0408] Furthermore, in the embodiment described above, the duct unit 60 was configured to have one opening that includes both the third opening 201 and the fourth opening 202, but it is also acceptable to have only one of the openings. In that case, either the first opening 73 or the second opening 74 on the image forming apparatus side can be brought into close contact with the third opening 201 or the fourth opening 202 via the sealing member 207. At this time, it is also possible to bring one of the first opening 73 or the second opening 74 on the image forming apparatus side into close contact and extend the other opening to a space where there is no risk of toner scattering.

[0409] Furthermore, in the embodiment described above, a configuration was shown in which the cooling duct 75 (see Figure 26) is formed between the duct unit 60 and the cartridge tray 30 or the lifting duct 69. However, it is not necessarily required to form it with the duct unit 60. In that case, the cooling duct 75 may be formed using only the cartridge tray 30 or the lifting duct 69.

[0410] In the embodiment described above, the intake port 203 was configured to draw in air directly from outside the image forming apparatus 100, and the exhaust port 204 was configured to exhaust air directly to the outside of the apparatus. However, it is not necessary to adopt such a configuration. For example, the intake port 203 may be configured to draw in relatively cool air from a space without heat sources such as the sheet cassette 12. Similarly, the exhaust port 204 may be configured to exhaust air into a space where there is no influence from heat inside the image forming apparatus 100.

[0411] Furthermore, the intake fan 62 and exhaust fan 63 are not necessarily required; the system may be configured to circulate airflow through the pressure difference between the exposure cooling airflow and the outside air without either or both of them.

[0412] Furthermore, the vertical orientation of the units and components was described in accordance with the arrangement of each unit in the cross-sectional view of the image forming apparatus 100 shown in Figure 2. However, the unit arrangement may also be such that the photosensitive drum 2 is positioned above the intermediate transfer belt 9, and the exposure head 4 is positioned above that, as in the top exposure method where the photosensitive drum 2 is exposed from approximately above. In that case, the vertical orientation described in the embodiment is reversed, and the duct unit 60 will be configured to descend just before the assembly position.

[0413] Furthermore, although the guide portion 103 is a curved surface and the guided portion 208 is a sloped surface, their relationship can be reversed, or combinations such as two curved surfaces or two slopes can be selected.

[0414] Furthermore, although the above-described embodiment illustrates a configuration in which the harness opening 252 is provided on the drum unit 23 side, the invention is not limited to this, and it may also be provided on the developing unit 24 side. By providing the harness opening 252 on the developing unit 24 side, which is located near the exposure head, it is possible to prevent it from affecting the airflow along the drum unit 23.

[0415] In the embodiment described above, an example was shown in which engaging claws 55b and 55c are provided on the housing support member 55 that constitutes the exposure head 4. However, engaging claws may also be provided on the components on the image forming apparatus 100 side. In that case, L-shaped engaging claws may be provided on the lifting duct 69, and engaging holes that engage with the engaging claws may be provided on the housing support member 55.

[0416] Furthermore, in the embodiment described above, a configuration was shown in which a recess 55f is provided in the housing support member 55 that constitutes the exposure head 4, but the recess may also be provided in a component on the image forming apparatus 100 side. In that case, a recess should be provided in the lifting duct 69 and a protrusion that engages with the recess should be provided in the housing support member 55.

[0417] Furthermore, in the embodiment described above, the sliding motion for mounting the exposure head 4 was performed from the front to the rear of the image forming apparatus 100, but it may also be configured to slide from the rear to the front. In that case, the shapes of the engaging claw and the engaging hole should be reversed in the front-to-back direction.

[0418] In the embodiment described above, the positioning of the photosensitive drum of the exposure head 4 in the two-axis direction and the ground connection were performed using the front positioning pin 45F, but this may also be done using the rear positioning pin 45B. Furthermore, the ground connection may be performed using both the front and rear positioning pins 45F and 45B. [Explanation of symbols]

[0419] 1 ...Image forming unit 2. Photosensitive drum (photoconductor) 3. Charging roller (charging means) 4. Exposure head (exposure means) 5. Developing sleeve (developer carrier) 7... Screw 9…Intermediate transfer belt 23... Drum unit (photoconductor unit) 24 ...Developing unit (developing means, developing unit) 26… Drum bearing 26F,26B…Engagement part 30 ... Cartridge tray (support member) 30a ... Rotating shaft 30c ... Second opening forming section 30d...Biasing part 31... Development Stay 40...fan 45F, 45B ... Positioning pin (positioning axis) 50 ... circuit board 51 ... LED (Light-emitting element) 52... Lens array 54 ...Housing (holding member) 55 ... Housing support member (holding member) 55D ...Bottom surface (opposite side) 55a...Aperture 55b,55c...Engagement claw 55f ... recessed 55g ... First opening forming section 57 …FFC connector 58 …FFC 58a ...Folded section 60... Duct unit (exposure cooling unit) 61…Opening 62 ... Intake fan 63 ... Exhaust fan 64…Opening 65 ... Rotating arm (rotating member) 66 ...Engagement Boss 67 ... Arm pressure spring 68B ... Arm retraction member 68F ... Arm retraction member 69... Lifting duct (exposure support member) 69B ... rear wall of the duct 69F... Duct front wall 69L ... Duct left wall 69L1 ... First inclined surface 69R... Right wall of the duct 69R1 ... Second inclined surface 69U...Top part (support part) 69U1 ... First upper surface 69U2 ... Second upper surface 69a...Aperture 69b,69c...Engagement hole 69d ... First engaging part 69e ... Second engagement part 69f ... protruding part 69g ...Second opening forming section 70, 71, 72... stickers 73 ...First opening 74 ...Second opening 76…shielding wall 100 ...Image forming apparatus 100B…Rear side plate 100C ... Sheet metal 100F…Front side plate 101... Front cover 101a ... Air intake 102 ...Inner door 103…Information Department 104...Support part 105 ... Fastening part 201 ... Third opening 202 ...Fourth opening 203 ... Air intake 204 ... Exhaust port 205 ... Intake duct 206... Exhaust duct 207...Sealing member 208...Guided part 209...Guided part 209...Supported part 210...part to be fastened 211 ... Fastening member 250 ... Positioning member 250a ... Regulatory Department 250a1 ... First contact surface 250a2 ... Second contact surface 250b...Biasing part 251 ... Conductive member 252 ... Harness opening 301 ... Development support member 301a ... First development guide section 301b ... Second development guide section 301c ... Bottom of the developing area 301d ... Opposite section 301e...Partition wall part 302 ... Drum support member 302a ...First drum guide section 302b ... Second drum guide section 302c ... bottom of the drum 302d ... Opposite section

Claims

1. A photoreceptor unit having a photoreceptor, An exposure means is positioned in close proximity to the photoreceptor and exposes the photoreceptor to form a latent image on the photoreceptor, A developing means for developing the latent image formed on the photoreceptor using toner, A photoreceptor support member guides the photoreceptor unit along the axial direction of the photoreceptor and detachably supports the photoreceptor unit, A developing support member guides the developing means along the axial direction of the photoreceptor and detachably supports the developing means, An exposure support member is provided between the photoreceptor support member and the developer support member, has an opening that communicates with the exposure means, integrally supports the exposure means, and moves integrally with the exposure means to an exposure position where the photoreceptor is exposed and to a retracted position where it is retracted from the exposure position. An exposure cooling unit that communicates with the opening of the exposure support member and cools the exposure means by airflow through the opening of the exposure support member, The device includes a sealing member that seals the gap between the exposure support member and the development support member and the gap between the exposure support member and the photoreceptor support member at the exposure position, The sealing member is positioned at a predetermined angle with respect to the direction of movement of the exposure support member. The exposure support member is Through the opening, on one side in a direction perpendicular to the axial direction of the photoreceptor, at a position facing the developing support member, there is a first duct wall having a first inclined surface forming the predetermined angle, Through the opening, on the other side in a direction perpendicular to the axial direction of the photoreceptor, at a position facing the photoreceptor support member, there is a second duct wall having a second inclined surface forming the predetermined angle, The sealing members are provided on the first inclined surface and the second inclined surface, respectively, and are at the predetermined angle. An image forming apparatus characterized by the following features.

2. The sealing member is a sheet material or a foamed sealing material. The image forming apparatus according to feature 1.

3. The predetermined angle formed by the sealing member is an angle between 20° and 90° with respect to the direction of movement of the exposure support member. The image forming apparatus according to claim 1 or 2.

4. The sealing member has a configuration in which the contact surface with the exposure support member or the developing support member that forms the gap, and the contact surface with the exposure support member or the photoreceptor support member that forms the gap, are inclined at the predetermined angle. The image forming apparatus according to any one of claims 1 to 3.

5. The first inclined surface is inclined in the direction of movement from the upstream side to the downstream side, away from the second duct wall. The second inclined surface is inclined in the direction of movement, moving away from the first duct wall from the upstream side to the downstream side. The image forming apparatus according to feature 1.

6. The exposure means performs exposure using an organic EL. The image forming apparatus according to any one of claims 1 to 5.

Images