Image forming device

Abstract

To achieve easy mounting of exposure means with an inexpensive configuration.SOLUTION: An image forming apparatus includes: exposure means that exposes a photoconductor; and an exposure support member that has a support portion for detachably supports the exposure means and is moved integrally with the exposure means in a first direction orthogonal to an axial direction of the photoconductor. The exposure means has a first engagement portion that is formed on a facing portion facing the support portion of the exposure support member in the first direction so as to protrude toward the exposure support member and further formed to extend in the axial direction of the photoconductor orthogonal to a protruding direction. The exposure support member has, on the support portion facing the exposure means, a second engagement portion that is formed at a position corresponding to the first engagement portion and engaged with the first engagement portion. The exposure means is mounted on the exposure support member by moving the exposure means in the first direction with respect to the exposure support member to engage the first engagement portion with the second engagement portion in the protruding direction and then moving the exposure means in the axial direction to engage the first engagement portion with the second engagement portion in an extending direction orthogonal to the protruding direction, and the exposure means is integrated with the exposure support member.SELECTED DRAWING: Figure 59

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus equipped with an exposure head that exposes a photosensitive member. [Background technology]

[0002] 2. Description of the Related Art Conventionally, the techniques described in Patent Documents 1 and 2 are known as techniques relating to exposure heads used in electrophotographic image forming apparatuses.

[0003] In Patent Document 1, an exposure head using an LED array system in which a plurality of light-emitting elements are arranged along the axial direction of the photosensitive member is used as an exposure head for forming a latent image on the photosensitive member.

[0004] The exposure head is composed of a circuit board, a rod lens array, a holder that supports them, a frame that covers the holder, and a pressing member that is installed between the holder and the frame and presses the holder against the photosensitive member.

[0005] Generally, the image forming device and the exposure head are electrically connected by a wire harness for power supply and control signal transmission, so a configuration is required in which, for example, an opening (not shown) is made in the frame, the harness is inserted through it, and the circuit board is connected.

[0006] The exposure head described in Patent Document 2 does not include a pressing member that presses the exposure head against the photosensitive member, and discloses a configuration in which the pressing member is provided in the image forming apparatus main body.

[0007] In this case, the exposure head is attached to the image forming apparatus body while the exposure head presses the pressing member in the direction opposite to the pressing direction, thereby deforming the pressing member.

[0008] The exposure heads described in Patent Documents 1 and 2 are precision parts, so it is desirable that they be configured to be easily replaceable in the unlikely event of an accidental breakdown. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 06056333 [Patent Document 2] Patent No. 04655713 Public Relations Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the configuration disclosed in Patent Document 1, the circuit board is not fixed to the frame and is biased by a pressing member, which causes the circuit board to move when connecting the harness, resulting in poor workability. Furthermore, the work must be done while the harness is being inserted into the frame, which raises concerns about further deterioration of workability.

[0011] Furthermore, since the exposure head is configured integrally with the pressing member, the replacement cost when replacing the exposure head may be higher than in a configuration that does not include a pressing member.

[0012] On the other hand, even if the image forming apparatus main body is equipped with a pressing member and the exposure head does not have a pressing member, as in the configuration disclosed in Patent Document 2, the exposure head must be attached while applying force to the pressing member with the exposure head. In this case, there is a risk that the exposure head, which is a precision component, may be hit and damaged.

[0013] SUMMARY OF THE INVENTION It is therefore an object of the present invention to realize an exposure head that is easy to mount with an inexpensive configuration. [Means for solving the problem]

[0014] A representative configuration of the present invention for achieving the above object includes a photosensitive body, an exposure means disposed in the vicinity of the photosensitive body and exposing the photosensitive body to light to form a latent image on the photosensitive body, and an exposure support member having a support portion for detachably supporting the exposure means, which is moved integrally with the exposure means in a first direction perpendicular to the axial direction of the photosensitive body, and is moved between an exposure position where the photosensitive body is exposed and a retracted position where the exposure means is retracted from the exposure position, and the exposure means is formed at an opposing portion facing the support portion of the exposure support member in the first direction so as to protrude toward the exposure support member, and is further formed at an opposing portion facing the support portion of the exposure support member ... in the axial direction of the photosensitive body perpendicular to the protruding direction. the exposure support member has a first engaging portion formed by extending in a direction perpendicular to the protruding direction, and the exposure means has a second engaging portion formed on the support portion facing the exposure means at a position corresponding to the first engaging portion and engaging with the first engaging portion, and the exposure means is attached to the exposure support member by moving the exposure means in the first direction relative to the exposure support member to engage the first engaging portion with the second engaging portion in the protruding direction, and then moving the exposure means in the axial direction to engage the first engaging portion with the second engaging portion in the extending direction perpendicular to the protruding direction, thereby integrating the exposure means with the exposure support member. [Effects of the Invention]

[0015] According to the present invention, it is possible to realize an inexpensive structure and easy installation of the exposure means. [Brief explanation of the drawings]

[0016] [Figure 1] Perspective view of an image forming apparatus [Figure 2] 2 is a schematic cross-sectional view of the image forming apparatus in FIG. 1. [Figure 3] 2 is a schematic cross-sectional view of the image forming apparatus in FIG. 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] Partially enlarged perspective view of an image forming apparatus [Figure 8] Perspective view of the cartridge tray [Figure 9] Perspective view of the cartridge tray [Figure 10] Cross-sectional view of the exposure head [Figure 11] Perspective view of the exposure head [Figure 12] Perspective view of the exposure head [Figure 13] (a), (b), and (c) are diagrams showing the substrate of the exposure head, and (d) and (e) are diagrams showing the lens array. [Figure 14] A perspective view of the board seen from the side where the LED is mounted (board surface) [Figure 15] A perspective view of the board seen from the side where the connector is mounted (back side of the board) [Figure 16] A perspective view of the exposure head from below with the substrate attached to the housing. [Figure 17] Enlarged view of the connector side of the exposure head in Figure 16 [Figure 18] FIG. 17 is a perspective view showing the exposure head in a state where the lens array is assembled in the housing in FIG. 16. [Figure 19] 1 is a perspective view of the connector side of an exposure head in which a housing and a housing support member are integrally formed, as viewed from below; [Figure 20] Perspective view of the cartridge tray [Figure 21] Bottom view of the cartridge tray and lifting duct [Figure 22] 21 is a cross-sectional view taken along the arrow XX in FIG. 20. [Figure 23] Cross-sectional view taken along arrow XX in Figure 20 [Figure 24] Cross-sectional view taken along arrow YY in Figure 20 [Figure 25] Cross-sectional view taken along arrow YY in Figure 20 [Figure 26] Cross section of exposure cooling airflow perpendicular to the optical axis [Figure 27] A perspective view of the exposure head, lifting duct, and rotating arm [Figure 28] A perspective view of the exposure head, lifting duct, and rotating arm [Figure 29] Cross section taken along arrow EE in Figure 37 [Figure 30] Cross section taken along arrow EE 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 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 section 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 section of the exhaust side of the exposure cooling airflow [Figure 40] Cross-section of the duct unit just before assembly [Figure 41] (a) and (b) Enlarged cross-sectional views of the duct unit positioning shape, (c) and (d) Enlarged cross-sectional views of the duct unit just before assembly [Figure 42] Cross section of Figure 39 taken along the arrow FF [Figure 43] Cross-sectional view of the photosensitive drum, exposure head, and rotating arm [Figure 44] 1 is a cross-sectional perspective view showing the positioning of the photosensitive drum and the exposure head on the front side; [Figure 45] 1 is a cross-sectional perspective view showing the positioning of the photosensitive drum and the exposure head on the rear side. [Figure 46] FIG. 10 is a perspective view showing a state after the positioning member is attached. [Figure 47] FIG. 10 is a perspective view showing a state before the positioning member is attached; [Figure 48] FIG. 10 is a perspective view showing the shape of a positioning member; [Figure 49] Right perspective view of the exposure head removed from the lifting duct [Figure 50]Front cross-sectional view of the exposure head removed from the lifting duct [Figure 51] Left perspective view of the exposure head removed from the lifting duct [Figure 52] Right perspective view of the exposure head placed on the lifting duct [Figure 53] Front cross-sectional view of the exposure head placed on the lifting duct [Figure 54] Left perspective view of the exposure head placed on the lifting duct [Figure 55] Cross-sectional view of the exposure head placed on the lifting duct [Figure 56] 1 is a perspective view of the vicinity of the conductive member when the exposure head is placed on the lifting duct. [Figure 57] Right perspective view of the exposure head attached to the lifting duct [Figure 58] Left perspective view of the exposure head attached to the lifting duct [Figure 59] Cross-sectional view of the exposure head attached to the lifting duct [Figure 60] FIG. 59 is an enlarged cross-sectional view of the engagement portion shown in FIG. [Figure 61] FIG. 10 is a perspective view of the vicinity of the conductive member in a state where the exposure head is attached to the lifting duct. [Figure 62] Right side cross section showing harness opening [Figure 63] Right perspective view of the FFC after excess length processing [Figure 64] Front cross-sectional view of FFC with excess length processed [Figure 65] Front cross-sectional view showing the FFC in the retracted position DETAILED DESCRIPTION OF THE INVENTION

[0017] The following describes embodiments of the present invention with reference to the drawings. Note that the dimensions, materials, shapes, relative positions, etc. of the components described below are not intended to limit the scope of the present invention unless otherwise specified.

[0018] (Image forming device) First, a schematic configuration of an image forming apparatus 100 will be described with reference to 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 embodiments may also be other image forming apparatuses, such as a printer that does not have a reading device. Furthermore, embodiments are not limited to color image forming apparatuses equipped with multiple photosensitive drums 2 as shown in Figures 2 and 3, but may also be color image forming apparatuses equipped with one photosensitive drum 2 or image forming apparatuses that form monochrome images.

[0019] 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 units 1") that form toner images of yellow, magenta, cyan, and black, respectively.

[0020] The image forming units 1Y, 1M, 1C, and 1K are provided with photosensitive drums 2Y, 2M, 2C, and 2K (hereinafter, collectively referred to simply as "photosensitive drums 2"), which are examples of photosensitive bodies. The photosensitive drums 2 may be photosensitive belts.

[0021] The image forming units 1Y, 1M, 1C, and 1K are also provided with charging rollers 3Y, 3M, 3C, and 3K (hereinafter also collectively referred to simply as "charging rollers 3") as charging means for charging the photosensitive drums 2Y, 2M, 2C, and 2K, respectively.

[0022] In addition, 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 as "exposure heads 4") as exposure means for exposing the photosensitive drums 2Y, 2M, 2C, and 2K.

[0023] Furthermore, the image forming units 1Y, 1M, 1C, and 1K are equipped with developing units 24Y, 24M, 24C, and 24K (hereinafter collectively referred to as "developing units 24") as developing means that develop the electrostatic latent images on the photosensitive drums 2 with toner and develop toner images of the respective colors on the photosensitive drums 2. The letters Y, M, C, and K attached to the reference numerals indicate the colors of the toner.

[0024] 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, i.e., the exposure head 4 is disposed below the photosensitive drum 2. The following description will be given on the assumption that the image forming apparatus employs the bottom exposure method. Note that, although not shown, an embodiment may also employ an image forming apparatus that employs an "top exposure method" in which the photosensitive drum is exposed from above.

[0025] The image forming apparatus 100 includes an intermediate transfer belt 9 onto 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 onto the intermediate transfer belt 9. The intermediate transfer belt 9 is disposed above the image forming unit 1. Note that, in addition to the intermediate transfer method using the intermediate transfer belt 9, a direct transfer method in which an image is directly transferred from the photosensitive drum 2 to paper may also be used.

[0026] The image forming apparatus 100 also includes a secondary transfer roller 16 as a transfer means for transferring the toner image on the intermediate transfer belt 9 onto the recording paper P transported from the feed section 11, and a fixing device 19 as a fixing means for fixing the secondarily transferred image onto the recording paper P.

[0027] Furthermore, toner bottles 22Y, 22M, 22C, and 22K (hereinafter collectively referred to as "toner bottles 22") that contain replenishment toner of each color are units that can be detached and replaced with respect to image forming apparatus 100. Toner bottles 22 are disposed above intermediate transfer belt 9. Toner bottles 22 replenish the appropriate amount of toner at the appropriate time to each of the development units provided in the four image forming units by a toner replenishment mechanism (not shown) from the corresponding toner bottles.

[0028] The image forming apparatus 100 also includes a feeding unit 11 that feeds recording paper P. The feeding unit 11 has sheet cassettes 12a and 12b, feeding rollers 13a and 13b, and registration rollers 15. The sheet cassettes 12a and 12b are disposed below the image forming unit 1. The recording paper P stored in the sheet cassettes 12a and 12b is fed one sheet at a time by the feeding rollers 13a and 13b, and is transported to the secondary transfer unit T2 at a predetermined timing by the registration rollers 15.

[0029] (Image formation process) Next, a brief description will be given of the image formation process of the image forming apparatus 100. The charging roller 3Y charges the surface of the photosensitive drum 2Y. The exposure head 4Y exposes the surface of the photosensitive drum 2Y 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 formed in a similar image formation process and transferred to the intermediate transfer belt 9 so as to be superimposed on top of each other.

[0030] The toner images of each color transferred onto the intermediate transfer belt 9 are transported by the intermediate transfer belt 9 to a secondary transfer unit T2. The toner images transported to the secondary transfer unit T2 are transferred all at once by a secondary transfer roller 16 onto a recording sheet P transported from a feed unit 11. The recording sheet P onto which the toner images have been transferred is transported to a fuser 19. The fuser 19 fuses the toner images onto the recording sheet P by heat and pressure. The recording sheet P that has been fixed by the fuser 19 is discharged by a discharge roller 20 onto a discharge tray 21 that is located above a toner bottle 22.

[0031] (Drum unit and developing unit) The replaceable drum unit 23 and developing unit 24 in the image forming apparatus 100 of this embodiment will be described as an example.

[0032] The photosensitive drum 2 and charging roller 3 described above are integrated into a unit (drum unit, drum cartridge) together with a cleaning device (not shown). An example of the configuration will be described with reference to FIGS. 4, 5, 6, and 7. FIGS. 4 and 5 are perspective views showing the schematic structure of the drum unit 23 (Y, M, C, K) and the developing unit 24 (Y, M, C, K) provided in the image forming apparatus 100. FIG. 6 is a diagram showing how the drum unit 23 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus main body. FIG. 7 is a diagram showing how the developing unit 24 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus main body.

[0033] Drum units 23Y, 23M, 23C, and 23K (hereinafter collectively referred to as "drum units 23") each having a photosensitive drum 2 are attached to the image forming apparatus 100. The drum units 23 are cartridges that are replaced by an operator such as a user or a maintenance technician. The drum units 23 rotatably support the photosensitive drums 2. Specifically, the photosensitive drums 2 are rotatably supported by the frame of the drum units 23. The drum units 23 may not necessarily be equipped with a charging roller 3 or a cleaning device.

[0034] Furthermore, image forming apparatus 100 is equipped with developing units 24Y, 24M, 24C, and 24K (hereinafter collectively referred to as "developing units 24") that are separate from drum unit 23, which is a photosensitive unit. Developing unit 24 includes developing sleeves 5Y, 5M, 5C, and 5K (hereinafter collectively referred to as "developing sleeves 5") that serve as developer carriers that carry developer, and screws 7Y, 7M, 7C, and 7K (hereinafter collectively referred to as "screws 7") that supply developer to developing sleeve 5 and agitate the developer. Developing unit 24 is a cartridge in which developing sleeve 5 and screw 7 are integrated, and is removed from the main body of image forming apparatus 100 and replaced by an operator, as shown in FIGS. 5 and 7.

[0035] Inside the developing unit 24, the toner is circulated and transported at high speed by the screw 7. The rotation speed of the screw 7 is relatively very high compared to the rotation speeds of the developing sleeve 5 and the photosensitive drum 2, so that the toner can be coated evenly and uniformly onto the developing sleeve 5.

[0036] The image forming apparatus 100 also includes a cartridge tray 30 (30Y, 30M, 30C, 30K) for each image forming unit (see FIGS. 8 and 9). The drum unit 23 and the developing unit 24 are supported by the cartridge tray 30 for each image forming unit, guided in the axial direction of the photosensitive drum, and inserted into or removed from the main body of the image forming apparatus 100.

[0037] The image forming apparatus 100 also includes a front panel 100F made of sheet metal and a rear panel 100B also made of sheet metal (see FIG. 34). The front panel 100F is a side wall provided on the front side of the image forming apparatus 100. The front panel 100F forms part of the housing of the apparatus body on the front side of the apparatus body of the image forming apparatus 100. The rear panel 100B is a side wall provided on the rear side of the image forming apparatus 100. The rear panel 100B forms part of the housing of the apparatus body on the rear side of the apparatus body of the image forming apparatus 100. The front panel 100F and the rear panel 100B are arranged facing each other on one side and the other side in the axial direction of the photosensitive drum, and a metal beam (not shown) bridges between them. The front panel 100F, the rear panel 100B, and the beam (not shown) each form part of the frame (housing) of the image forming apparatus. Here, with respect to the image forming apparatus of this embodiment 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.

[0038] The cartridge tray 30 is attached at one end to a front side plate 100F (see FIG. 34) and at the other end to a rear side plate 100B (see FIG. 34) in the axial direction of the photosensitive drum. The cartridge tray 30 will be described later.

[0039] The drum unit 23 and the developing unit 24 deteriorate as the image forming process is repeated, so they are in the form of units (cartridges) that can be replaced or detached for maintenance.

[0040] 3 shows the arrangement of the drum unit 23, the developing unit 24, and the exposure head 4 when replacing or removing them. In the image forming apparatus shown in FIG. 3, unlike the image forming apparatus shown in FIG. 2, it can be seen that the developing unit 24 and the exposure head 4 are retracted and separated from the photosensitive drum 2.

[0041] This is because if the developing unit 24 and the exposure head 4 are kept close to the photosensitive drum 2 as shown in FIG. 2, dynamic interference when attaching or detaching the units may damage each unit, or even make it impossible to remove the units.

[0042] For this reason, when the unit is attached or detached, the developing unit 24 and exposure head 4 are retracted and separated from the photosensitive drum 2 as shown in FIG. 3 by a retraction mechanism including the developing stay 31, the pivoting arm 65, and the lifting duct 69, which will be described later.

[0043] Drum unit 23 and developing unit 24 are inserted and removed from the front side of image forming apparatus 100, and are mounted in predetermined positions (mounting positions) on the main body of image forming apparatus 100.

[0044] Image forming apparatus 100 is provided with inner doors 102Y, 102M, 102C, and 102K (hereinafter collectively referred to as "inner door 102") that cover the front sides of both drum unit 23 and developing unit 24 that are installed in the installation positions. As shown in Figures 8 and 9, one end of inner door 102 is fixed to the front side of cartridge tray 30 by a hinge, and is rotatable relative to cartridge tray 30 by the hinge.

[0045] The inner door 102 is a necessary member for protecting each unit and for making it difficult for the photosensitive drum 2 to be exposed to light in processes other than the image formation process, and is disposed in a position facing the front of the units of each color in the attachment / detachment direction.

[0046] Furthermore, a front cover 101 that forms the exterior of the device is provided on the front side of the image forming apparatus 100. One end of the front cover 101 is fixed to the front side of the device body of the image forming apparatus 100 by a hinge, and the front cover 101 is rotatable relative to the device body of the image forming apparatus 100 by the hinge. The front cover 101 is provided forward of the inner door 102 in the axial direction of the photosensitive drum. In the closed state shown in FIG. 1, the front cover 101 entirely covers the multiple inner doors 102 that are lined up in the left-right direction, forming the exterior of the front side of the device.

[0047] Therefore, the replacement work of drum unit 23 and developing unit 24 is performed by an operator in the following procedure. The operator opens front cover 101 as shown in Fig. 4, then opens inner door 102 as shown in Fig. 5, and removes drum unit 23 (Fig. 6) or developing unit 24 (Fig. 7) from the main body of the apparatus. Then, a new drum unit 23 or developing unit 24 is inserted, inner door 102 is closed, and front cover 101 is closed to complete the replacement work.

[0048] The retraction mechanism for the developing unit 24 and the exposure head 4 is linked to the opening of the inner door 102, and retracts the developing unit 24 and the exposure head 4 from the photosensitive drum 2. This retraction mechanism (developing stay 31, rotating arm 65, and lifting duct) will be described later.

[0049] In the following description, the front panel side of the apparatus body is defined as the front side (near side or front side), and the rear panel side is defined as the rear side (rear side or back side). Furthermore, when the photosensitive drum 2K on which the electrostatic latent image for the black toner image is formed is used as a reference, the side on which the photosensitive drum 2Y on which the electrostatic latent image for the yellow toner image is formed is defined as the left side. When the photosensitive drum 2Y on which the electrostatic latent image for the yellow toner image is formed is used as a reference, the side on which the photosensitive drum 2K on which the electrostatic latent image for the black toner image is formed is defined as the right side. Furthermore, the direction perpendicular to the front-rear and left-right directions defined here, and pointing vertically upward, is defined as the up direction, and the direction perpendicular to the front-rear and left-right directions defined here, and pointing vertically downward is defined as the down direction. The defined front direction F, rear direction B, right direction R, left direction L, up direction U, and down direction D are shown in FIG. 1.

[0050] In addition, the axial direction of the photosensitive drum 2 described below is the direction that coincides with the front-to-rear direction (front-to-rear direction) shown in FIG. 1. The longitudinal direction of the exposure head 4 also coincides with the front-to-rear direction shown in FIG. 1. That is, the axial direction of the photosensitive drum 2 and the longitudinal direction of the exposure head 4 coincide with each other. Furthermore, one end side in the axial direction of the photosensitive drum 2 means the front side as defined here, and the other end side means the rear side as defined here. One end side and the other end side in the front-to-rear direction also correspond to the front side and rear side as defined here. One end side in the left-to-right direction means the left side as defined here, and the other end side means the right side as defined here.

[0051] (Exposure head) Next, the exposure head 4 will be described with reference to 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 as seen from above. Figure 12 is a perspective view of the exposure head 4 as seen from below.

[0052] The exposure head 4 has an elongated shape (longitudinal shape) extending in the axial direction of the photosensitive drum 2. The exposure head 4 includes a substrate 50, light-emitting elements 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 (described later) and a housing support member 55 that supports the housing 54. Here, the exposure head 4 includes LEDs 51 (Light Emitting Diodes) as light-emitting elements that emit light.

[0053] (Substrate and lens array) Here, the substrate 50 and lens array 52 of the exposure head 4 will be described with reference to 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 as seen from the side on which the LEDs are mounted (the front surface of the substrate). Figure 15 is a perspective view of the substrate as seen from the side on which the FFC connector is mounted (the back surface of the substrate). One side of the arrow in the figure indicates the front side of the image forming apparatus 100, and the other side indicates the rear side of the image forming apparatus 100.

[0054] An LED chip 53 is mounted on the substrate 50. As shown in Figures 13(a), 14, and 15, the LED chip 53 is provided on one surface of the substrate 50, and a long FFC connector 57 is provided on the other surface. The one surface of the substrate 50 here refers to the surface (top surface, front surface) on which the LED chip 53 is provided. The other surface of the substrate refers to the surface (bottom surface, back surface) opposite to the side on which the LED chip 53 is provided.

[0055] The FFC connector 57 is attached to the other surface (bottom surface, back surface) of the board 50 so that its longitudinal direction is along the longitudinal direction of the board 50. The long FFC connector 57 is provided on the front side of the image forming apparatus 100 (one side in the longitudinal direction of the board 50). 50 Each LED chip 53To the FFC connector 57, one end of a flexible flat cable 58 (see FIG. 26, hereinafter referred to as FFC) as an example of a cable is connected.

[0056] The control circuit section of the image forming apparatus 100 is provided with a board (not shown) that includes a control section and a connector. The other end of the FFC 58 is connected to the connector. That is, the FFC 58 electrically connects the board (control circuit section) of the apparatus main body with the board 50 of the exposure head 4. A control signal (drive signal) is input from the control circuit section of the apparatus main body of the image forming apparatus 100 to the board 50 of the exposure head 4 via the FFC 58 and the FFC connector 57. The control signal is transferred to each LED chip 53. The LED chips 53 are driven (to emit light or turn off) by the control signal input to the board 50.

[0057] The LED chips 53 mounted on the substrate 50 will be described in more detail. As shown in FIGS. 13(b) and 13(c), LED chips 53-1 to 53-29 (29 chips) each having a plurality of LEDs 51 (an example of a light-emitting element) arranged thereon are arranged on one surface of the substrate 50. Each of the LED chips 53-1 to 53-29 has 516 LEDs 51 arranged in its longitudinal direction. The center-to-center distance k2 between adjacent LEDs 51 in the longitudinal direction of the LED chip 53 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 are arranged such that the center-to-center distance k2 between adjacent LEDs 51 in the longitudinal direction of the LED chips 53-1 to 53-29 is 21.16 μm. Therefore, the exposure range of the exposure head 4 in this embodiment is approximately 314 mm. The length of the photosensitive layer in the axial direction of the photosensitive drum 2 is 314 mm or more. 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 of this embodiment has an exposure range that can form images on A4 size recording paper and A3 size recording paper.

[0058] The LED chips 53-1 to 53-29 are arranged in a staggered pattern in the axial direction of the photosensitive drum 2. Specifically, the LED chips 53-1 to 53-29 are arranged alternately in two rows along the axial direction of the photosensitive drum 2. That is, as shown in FIG. 13(b), counting from the left, the odd-numbered LED chips 53-1, 53-3, ... 53-29 are mounted in a row in the longitudinal direction of the substrate 50. Also, counting from the left, the even-numbered LED chips 53-2, 53-4, ... 53-28 are mounted in a row in 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), in the longitudinal direction of the LED chip 53, the center-to-center distance k1 between the LEDs 51 arranged between one end of one LED chip 53 and the other end of the other LED chip 53 on different adjacent LED chips 53 can be made equal to the center-to-center distance k2 between adjacent LEDs 51 on one LED chip 53.

[0059] In this embodiment, the light emitting element is a semiconductor LED, which is a light emitting diode, but it may also be, for example, an OLED (Organic Light Emitting Diode). This OLED is also called an organic EL (Organic Electro-Luminescence), and is a current-driven light emitting element. An OLED is, for example, a TFT (Thin Film Transistor ) are arranged in a line on the substrate along the main scanning direction (axial direction of the photosensitive drum 2), and are electrically connected in parallel by power supply wiring also provided along the main scanning direction.

[0060] Next, the lens array 52, which is a lens assembly, will be described. FIG. 13(d) is a schematic diagram of the lens array 52 as viewed from the photosensitive drum 2 side. FIG. 13(e) is a schematic perspective view of the lens array 52. ​​As shown in FIG. 13(d), the lens array 52 focuses light emitted from the light-emitting elements onto the photosensitive drum 2. The lens array 52 is a lens assembly having a plurality of lenses. These lenses are arranged in two rows along the arrangement direction of the plurality of LEDs 51. The lenses are alternately arranged such that one lens in one row is in contact with both of the adjacent lenses in the arrangement direction of the lenses in the other row. Each lens is a cylindrical glass rod lens and has a light incident surface 52b onto which light emitted from the LEDs 51 enters and a light exit surface 52a from which light incident from the light incident surface exits (see FIG. 10). The material of the lens is not limited to glass and may be plastic. The shape of the lens is also not limited to cylindrical and may be polygonal, such as a hexagonal prism.

[0061] The dotted line Z in Figure 13(e) indicates the optical axis of the lens. The exposure head 4 is moved in a direction generally along 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) described later. The optical axis of the lens here refers to the line connecting the center of the light-emitting surface of the lens to 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 lenses. Strictly speaking, the multiple lenses in the lens array 52 may be slightly tilted relative to each other. This is due to assembly tolerances. However, deviations within the tolerance range will not be taken into account when defining the direction of the optical axis. Therefore, the optical axes of the multiple lenses are considered to be in the same direction. The lens array 52 serves to focus light emitted from the LED 51 onto the surface of the photosensitive drum 2.

[0062] When assembling the exposure head 4, the mounting position of the lens array 52 relative to the housing 54 is adjusted so 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-exiting surface of the lens and the surface of the photosensitive drum 2.

[0063] (Housing) 10, the housing 54 holds the lens array 52 and the substrate 50. In this embodiment, the housing 54 is a metal member formed by bending a plate material such as a galvanized steel plate or a cold-rolled steel plate that has been plated.

[0064] As described above, the housing 54 is made of metal. For example, the housing 54 is formed into a U-shape by pressing a metal plate such as a thin iron plate. The shape of the housing 54 will be described below.

[0065] 10, the housing 54 has a flat surface (facing surface) 54U in which a first opening 54a into which the lens array 52 is inserted is formed. The flat surface 54U faces the photosensitive drum 2 in the optical axis direction of the lenses of the lens array 52. ​​Note that this flat surface 54U is not limited to a flat surface, and may be a slightly curved surface. The housing 54 also has an extension 54R that extends from one side of the flat surface 54U in the width direction in a direction away from the photosensitive drum 2. The housing 54 also has an extension 54L that extends from the other side of the flat surface 54U in the width direction in a direction away from the photosensitive drum 2.

[0066] The extending portions 54R and 54L form a board support portion in the housing 54 for supporting the board 50 inserted through the second opening 54b. 54U The lens array 52 and the substrate support portions (extension portions 54R, 54L) are integral with each other and form a housing 54 that holds the lens array 52 and the substrate 50, and the cross section of the housing 54 is formed in a substantially U-shape. By forming the housing 54 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 substrate support portions (extension portions 54L, 54R) that extend from the flat portion 54U to the side away from the photosensitive drum.

[0067] The substrate 50 is inserted from the second opening 54b, i.e., from the lower side of the U-shaped housing 54, and is adhered with an adhesive to the inside of each substrate support portion (the inside of the extension portion 54L and the inside of the extension portion 54R). Note that the position of the substrate 50 in the focus direction is determined by a jig (not shown), and therefore the exposure head 4 does not include a positioning means for the substrate 50 in the focus direction.

[0068] The lens array 52 is also inserted into the first opening 54a formed in the flat portion 54U and bonded to the flat portion 54U with an adhesive. The lens array 52 is fixed to the flat portion 54U (housing 54) after adjusting the position and tilt in the focus direction using a jig so that the distance in the focus direction between all of the LED chips 53 mounted on the substrate 50 and the lens array 52 is a predetermined value. The lens array 52 is also fixed to the flat portion 54U with an adhesive at multiple locations in the longitudinal direction. That is, the exposure head 4 of this embodiment has multiple bonding locations in the longitudinal direction of the flat portion 54U where the lens array 52 inserted into the first opening 54a is adhesively fixed to the flat portion 54U.

[0069] After the positions of the substrate 50 and the lens array 52 are adjusted 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 and 54R) is sealed in the longitudinal direction with a sealant 59, as shown in FIGS. 16 and 17. FIG. 16 is a perspective view, seen from below, of the exposure head 4, showing the state in which the substrate 50 on which the LEDs 51 are mounted is assembled into the housing 54. FIG. 17 is an enlarged view of the front side of the exposure head shown in FIG. 16. This prevents the LEDs 51 from being contaminated by toner or dust from 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.

[0070] Similarly, a sealant 59 is applied to the gap between the lens array 52 inserted into the first opening 54a and the housing 54 (flat surface portion 54U), and the gap is sealed in the longitudinal direction by the sealant 59, as shown in FIG. 18. FIG. 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 FIG. 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 opening 54a. This reduces the possibility that dust such as toner will enter through the gap between the side wall of the lens array 52 and the first opening 54a and block the light emitted from the LEDs 51. Naturally, the sealant 59 seals not only the gap between one side wall of the lens array 52 and the edge of the first opening 54a, but also the gap between the other side wall of the lens array 52 and the edge of the first opening 54a. The other sidewall of the lens array 52 refers to the sidewall opposite to the sidewall on one side 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 LEDs 51 from being contaminated by toner or dust from outside.

[0071] As described above, the substrate 50 and the lens array 52 are held by the housing 54, so that the LED 51 and the incident surface of the lens 52b As a result, the light emitted from the LED 51 is incident on the lens surface. 52b and the light exits from the lens 52a The light is emitted from the LEDs 51 toward the photosensitive drum 2. In this embodiment, the light emitted from the three LEDs 51 (the plurality of LEDs 51) can pass through the same lens. Furthermore, even if the light is emitted from one LED 51, the light can pass through multiple lenses because the light travels radially. In other words, the light emitted from the plurality of LEDs 51 passes through the lens array 52 (some of the plurality of lenses that the lens array 52 has) to expose the photosensitive drum 2.

[0072] (Housing support member) As shown in FIGS. 11 and 12 , the housing support member 55 supports the housing 54, which holds the substrate 50 and the lens array 52, in the longitudinal direction and is integral with the housing 54. The housing support member 55 is a longitudinal member extending in the axial direction of the photosensitive drum 2. As shown in FIG. 10 , the housing support member 55 is formed in a U-shape. 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 facing the left side wall 55L, and a bottom surface portion 55D which faces the flat surface portion 54U of the housing 54 between the left side wall 55L and the right side wall 55R. A plurality of openings 55a are formed in the bottom surface portion 55D of the housing support member 55 in the longitudinal direction, which is the axial direction of the photosensitive drum 2.

[0073] The opening 55a of the housing support member 55 is provided at a position facing the surface (rear surface of the board 50) opposite to the mounting surface (front surface of the board 50) on which the LEDs 51 are mounted of the board 50. The opening 55a is provided between the left side wall 55L and the right side wall 55R in the short direction perpendicular to the long direction.

[0074] 22, the left side wall 55L, which is a first side wall, 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 short direction perpendicular to the axial direction of the photosensitive drum 2. As shown in FIG. 11, 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.

[0075] 22, the right side wall 55R, which is a second side wall, is provided on the other side in the short direction between the housing 54 and the drum unit 23, which is an adjacent part adjacent to the housing 54. Like the left side wall, the right side wall 55R is also provided in the axial direction of the photosensitive drum 2 so as to separate the housing 54 and the drum unit 23.

[0076] By providing this housing support member 55 integrally with the housing 54, the airflow sent from a duct unit 60 (described later) is blown onto the back surface of the substrate 50 through an opening 55a between a left side wall 55L and a right side 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.

[0077] In this way, 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 side wall 55L, and is separated from the drum unit 23 by the right side wall 55R. Therefore, the airflow that cools the exposure head 4 and is introduced onto the back surface of the substrate 50 does not leak onto the side of the developing unit 24 adjacent to the exposure head 4, and toner in the developing unit 24 can be prevented from scattering inside the image forming apparatus.

[0078] (engaging claws) 11 and 12, the exposure head 4 has engagement claws 55b and 55c which are first engagement portions. The engagement 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.

[0079] In the housing support member 55 of the exposure head 4, the bottom surface portion 55D between the opening 55a at one longitudinal end (front side) and the adjacent opening 55a is referred to as the first bottom surface portion 55D1. Similarly, the bottom surface portion 55D between the opening 55a at the other longitudinal end (rear side) and the adjacent opening 55a is referred to as the second bottom surface portion 55D2. An engagement claw 55b that engages with the lift-up duct 69 is provided on the lower surface of the first bottom surface portion 55D1. An engagement claw 55c that engages with the lift-up duct 69 is provided on the lower surface of the second bottom surface portion 55D2. The first bottom surface portion 55D1 and the second bottom surface portion 55D2, i.e., the bottom surface portion 55D, are opposing portions that face the upper surface portion 69U of the lift-up duct 69.

[0080] The first engagement portions, ie, engagement claws 55b and 55c, are formed on the bottom surface portion 55D so as to protrude toward the lifting / lowering duct 69 in the movement direction of the lifting / lowering duct 69, which will be described later, and are further formed so as to extend in the axial direction of the photosensitive drum 2, which is perpendicular to the protruding direction.

[0081] Specifically, the engagement claws 55b and 55c of the exposure head 4 are formed to protrude toward the lifting duct 69 and are formed in a substantially L-shape that extends in the axial direction of the photosensitive drum 2, which is perpendicular to the protruding direction. As will be described later, when the exposure head 4 is slid, the tips of the substantially L-shaped engagement claws 55b and 55c engage with the edges of the engagement holes 69b and 69c by snap-fitting, and the exposure head 4 becomes one with the lifting duct 69.

[0082] (shielding wall) The housing support member 55 is provided with a shielding wall 76. The shielding wall 76 will be described with reference to Figure 19. Figure 19 is a perspective view of the exposure head 4, in which the housing 54 and the housing support member 55 are integrally formed, as viewed from below.

[0083] For reasons described below, the housing support member 55 has a shielding wall 76 for separating the connector area where the FFC connector 57 is arranged on the back surface of the substrate 50 from the duct area where the opening 55a is located rearward in the fore-and-aft direction from the connector area.

[0084] The connector 57 is disposed at a position shifted toward one end from the center in the longitudinal direction of the substrate 50. On the other hand, a plurality of openings 55a are formed on the substrate 50 at the other end side of the connector 57 in the longitudinal direction. A shielding wall 76 is provided to separate the openings 55a and the connector 57.

[0085] 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 board 50 so as to protrude toward the back surface of the board 50. The shielding wall 76 is provided between the left side wall 55L and the right side wall 55R of the housing support member 55. The shielding wall 76, between the left side wall 55L and the right side wall 55R, separates a duct area on the back surface of the board 50 held in the housing 54 from a connector area of ​​the FFC connector 57 mounted on the board 50. Here, the duct area on the back surface of the board 50 is an area facing an opening 55a provided in the bottom surface 55D of the housing support member 55, and is an area (range La shown in FIG. 20 ) that communicates with an opening 61 of the duct unit 60 via a closed space formed by a lifting duct 69 (described later) and a cartridge tray 30. The connector area mounted on the back surface of the substrate 50 is the area where the FFC connector 57 is mounted on the back surface of the substrate, which is the area outside the duct area (range La) in the axial direction of the photosensitive drum 2, and is the area forward of the duct area in the front-to-back direction, which is the area shown as range Lc in Figure 20.

[0086] 20 is provided on the housing support member 55. This prevents air blown onto the back surface of the board 50 held in the housing 54 from the opening 55a of the housing support member 55 from leaking toward the FFC connector 57, thereby preventing a decrease in the cooling capacity for the board 50.

[0087] The shielding wall 76 separates the duct area from the connector area so that the connector area is outside the duct area and is located on one end side of the photosensitive drum 2 in the axial direction. The shielding wall 76 also separates the duct area from the connector area so that the connector area is located on the front side in the front-to-rear direction of the image forming apparatus 100. Therefore, the FFC connector 57 is positioned as far forward as possible to maximize the length of the range La. This prevents air blown onto the back surface of the circuit board 50 from being blocked by the FFC 58 connected to the FFC connector 57 and flowing in an unintended direction. In other words, air blown from the duct unit 60 (described later) toward the exposure head 4 is blown onto the back surface of the circuit board 50 without being blocked by the FFC 58 connected to the FFC connector 57. The air blown onto the back surface of the circuit board 50 tends to flow along the longitudinal direction of the circuit board 50 through the space between the left side wall 55L and the right side wall 55R of the housing support member 55. At this time, the air flow 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 side) to the other side (rear side). Therefore, the airflow blown onto the back surface of the substrate 50 from the duct unit 60 (described later) can be directed in the intended direction, and toner scattering inside the image forming apparatus due to airflow flowing in an unintended direction can be suppressed.

[0088] In Figure 26, range Li and range Lo are the ranges when range La, which is the duct area, is divided 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, the intake side and the exhaust side. Range Lo is the exhaust side range when range La is divided into two equal parts, the intake side and the exhaust side. Range Ls is the range of range La, which is the duct area, in range Li on the intake side, where the cross-sectional area of ​​the airflow in the duct is locally narrowed.

[0089] As described above, the exposure head 4 is configured as an integrated head unit by the substrate having the LEDs, the lens array made up of a plurality of lenses, the housing 54, and the housing support member 55.

[0090] (Lift 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 line XX in Figure 20. Figures 27 and 28 are perspective views of the exposure head 4, the lifting duct 69, and the pivot arm 65.

[0091] The lifting duct 69 is an exposure support member that detachably supports the exposure head 4, and is provided in the main body of the image forming apparatus 100 together with a cartridge tray 30, which will be described later.

[0092] The lifting duct 69 is provided between a developing device support member 301 that supports the developing unit 24 of the cartridge tray 30, which will be described later, and a drum support member 302 that supports the drum unit 23. The lifting duct 69 is provided between the developing device support member 301 and the drum support member 302 of the cartridge tray 30, so as to be movable between an exposure position (see FIGS. 22 and 24) where the photosensitive drum 2 is exposed to light and a retracted position (see FIGS. 25 and 23) where the photosensitive drum 2 is retracted from the exposure position. Both longitudinal ends of the lifting duct 69 are supported from below by a pivot arm 65, which will be described later. The lifting duct 69 is moved by the pivot arm 65 together with the exposure head 4 in a direction perpendicular to the axial direction of the photosensitive drum 2 (first direction, movement direction). The lifting duct 69 is moved to the exposure position or the retracted position by the rotation of the pivot arm 65.

[0093] The lifting duct 69 has a longitudinal shape that extends in the front-to-rear direction (the axial direction of the photosensitive drum) like the exposure head 4 so that it can support the entire exposure head 4, and its central part has a shape with openings at the top and bottom. The lifting duct 69 forms a duct with one opening 69a communicating with the opening 55a of the exposure head 4 and the other opening 64 communicating with the opening 61 of the duct unit 60. The lifting duct 69 supports the exposure head 4 and also forms part of a duct that cools the exposure head 4.

[0094] The lifting duct 69 is provided on an upper surface 69U ( Figure 26 ) is provided in the upper surface portion 69U of the lifting duct 69. A plurality of openings 69a are provided in the longitudinal direction, which is the axial direction of the photosensitive drum 2. The lifting duct 69 has a duct left wall 69L, a duct right wall 69R facing the duct left wall 69L, a duct front wall 69F, and a duct rear wall 69B facing the duct front wall 69F. The duct left wall 69L, the duct right wall 69R, the duct front wall 69F, and the duct rear wall 69B are provided integrally with the upper surface portion 69U so as to surround the periphery of the upper surface portion 69U, i.e., so as to surround the openings 69a provided in the upper surface portion 69U. As a result, the lift duct 69 has an upper surface portion 69U, a duct left wall 69L, a duct right wall 69R, a duct front wall 69F, and a duct rear wall 69B integrally formed, and has openings at the top and bottom. The lift duct 69 forms a duct (closed space) that circulates airflow from a duct unit 60 (described later) between the duct walls and through openings 69a in the upper surface portion 69U to the exposure head 4.

[0095] The multiple openings 69a are provided at positions facing the multiple openings 55a provided in the bottom surface 55D of the housing support member 55. In other words, the openings 69a of the lifting duct 69 are provided at positions facing the rear surface of the substrate 50, similar to the openings 55a of the housing support member 55. In other words, the lifting duct 69 has openings 69a that communicate with the openings 55a of the exposure head 4.

[0096] The duct left wall 69L, which is the first duct wall, is provided through the opening 69a on the left side, which is one side in the short direction perpendicular to the axial direction of the photosensitive drum 2. That is, the duct left wall 69L is provided along the axial direction of the photosensitive drum 2 from the duct front wall 69F to the duct rear wall 69B at a position facing the developing unit 24, which is the developing means.

[0097] The duct left wall 69L has a first inclined surface 69L1 that is inclined from upstream to downstream in a direction away from the duct right wall 69R in the movement direction from the exposure position to the retracted position. The first inclined surface 69L1 is inclined in the same manner from the duct front wall 69F to the duct rear wall 69B. The first inclined surface 69L1 is provided at a position of the duct left wall 69L facing the developing device support member 301, and forms a predetermined angle θ2 with respect to the movement direction (the direction of arrow G shown in FIG. 22).

[0098] The duct right wall 69R, which is the second duct wall, is provided on the right side, that is, the other side in the short direction, through the opening 69a. That is, the duct right wall 69R is provided along the axial direction of the photosensitive drum 2 from the duct front wall 69F to the duct rear wall 69B at a position facing the drum unit 23, which is an adjacent part adjacent to the elevation duct 69.

[0099] The duct right wall 69R has a second inclined surface 69R1 that is inclined from upstream to downstream in a direction away from the duct left wall 69L in the movement direction from the exposure position to the retracted position. The second inclined surface 69R1 is inclined in the same manner from the duct front wall 69F to the duct rear wall 69B. The second inclined surface 69R1 is provided at a position on the duct right wall 69R opposite the drum support member 302 and forms a predetermined angle θ1 with respect to the movement direction (the direction of arrow G shown in FIG. 22).

[0100] A duct front wall 69F, which is a third duct wall, is provided outside the plurality of openings 69a provided in the upper surface portion 69U in the axial direction of the photosensitive drum.

[0101] A duct rear wall 69B, which is a fourth duct wall, is provided outside the plurality of openings 69a provided in the upper surface portion 69U in the axial direction of the photosensitive drum.

[0102] The plurality of openings 69a provided in the upper surface 69U of the lifting duct 69 are provided between the duct left wall 69L and the duct right wall 69R, and between the duct front wall 69F and the duct rear wall 69B.

[0103] In other words, the lifting duct 69 is formed by these duct walls into a hollow shape with openings at the top and bottom, with no openings facing the developing unit 24 and the drum unit 23.

[0104] Therefore, the lifting duct 69 allows the airflow generated by the duct unit 60, which will be described later, to flow against the back surface of the substrate 50 of the exposure head 4 through an opening 64, which will be described later, and an opening 69a between the duct left wall 69L and the duct right wall 69R. Therefore, the lifting duct 69 can allow the airflow generated by the duct unit 60 to flow against the back surface of the substrate 50 of the exposure head 4 without leaking to the adjacent developing unit 24 or drum unit 23, thereby reducing toner scattering inside the device.

[0105] Furthermore, the duct front wall 69F and the duct rear wall 69B extend further downward in the movement direction than the duct left wall 69L and the duct right wall 69R. In other words, the duct front wall 69F and the duct rear wall 69B are ribs that protrude in the direction of the duct unit 60 (described later) on both longitudinal outer sides of the opening 69a that communicates with the exposure head 4.

[0106] The lifting duct 69 integrally supports the exposure head 4 and communicates with the duct unit 60 described below, thereby forming a duct (part of the second cooling duct) that circulates the airflow from the duct unit 60 through the opening 69a to the exposure head 4. The duct walls 69F, 69B as ribs form part of the duct at the exposure position.

[0107] The duct front wall 69F and the duct rear wall 69B, together with the cartridge tray 30 described later, form an opening 64 (see FIG. 21) that communicates with an opening 61 (see FIG. 35) of the duct unit 60 described later.

[0108] Furthermore, the lifting duct 69 has a first engagement portion 69d and a second engagement portion 69e at both longitudinal ends thereof that engage with the pivot arm 65. The first engagement portion 69d is provided on the outer side of the duct front wall 69F at one longitudinal end. The first engagement portion 69d is also provided on the outer side of the region where the FFC connector 57 is provided, which is located on the outer side of the duct front wall 69F at one longitudinal end. The second engagement portion 69e is provided on the outer side of the duct rear wall 69B at the other longitudinal end.

[0109] Therefore, the area where first engagement portion 69d is provided (area Lm in FIG. 20) and the area where second engagement portion 69e is provided (area Lm in FIG. 20) are provided outside the duct area (area La in FIG. 20) in which opening 69a is surrounded by a duct wall. In other words, the duct area (area La in FIG. 20) in which opening 69a is surrounded by a duct wall is provided between the area where first engagement portion 69d is provided (area Lm in FIG. 20) and the area where second engagement portion 69e is provided (area Lm in FIG. 20).

[0110] The area where the FFC connector 57 is provided (area Lc in Figure 20) is outside the duct area (area La in Figure 20) that forms a duct in which the opening 69a is surrounded by a duct wall, and is located between the duct area and the area where the first engagement portion 69d is provided (area Lm in Figure 20).

[0111] Furthermore, the area La forming the duct includes most of the board 50 on which the LEDs 51 are mounted, and by blowing airflow onto this area La, it is possible to sufficiently cool the exposure head 4. The area Lc is the mounting area for the FFC connector 57 of the signal line that transmits the drive signal to the board 50 on which the LEDs 51 are mounted. No opening that forms a duct is provided in the area Lc, but as described above, the area La is configured to provide necessary and sufficient cooling.

[0112] As a result, air taken in from outside the apparatus by duct unit 60 (described later) passes through lifting duct 69 and is blown from opening 55a of exposure head 4 onto the rear surface of substrate 50 (see FIG. 37). In addition, the airflow blown onto the rear surface of substrate 50 from opening 55a of exposure head 4 is exhausted to the outside of the apparatus by duct unit 60 through lifting duct 69 (see FIG. 39).

[0113] (Engagement hole) 26, the lifting duct 69 has engagement holes 69b and 69c which are second engagement parts. The engagement holes 69b and 69c which are second engagement parts engage with the engagement claws 55b and 55c which are first engagement parts of the exposure head 4 by snap-fitting.

[0114] In the lift duct 69, the upper surface portion 69U between the opening 69a at one longitudinal end (front side) and the adjacent opening 69a is referred to as a first upper surface portion 69U1. Similarly, the upper surface portion 69U between the opening 69a at the other longitudinal end (rear side) and the adjacent opening 69a is referred to as a 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 portion 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.

[0115] The engagement holes 69b and 69c, which are the second engagement portions, are formed on an upper surface portion 69U facing the exposure head 4 at positions corresponding to the engagement claws 55b and 55c.

[0116] This allows the exposure head 4 to be detachably attached to the image forming apparatus 100. The exposure head 4 is moved (downward direction D shown in FIG. 49) so that the engagement claws 55b and 55c of the exposure head 4 drop into the engagement holes 69b and 69c of the lift-up duct 69, respectively, and the bottom surface 55D of the exposure head 4 comes into contact with the upper surface 69U of the lift-up duct 69. In other words, the exposure head 4 is moved in a direction perpendicular to the axial direction relative to the lift-up duct 69, and the engagement claws 55b and 55c are engaged in the protruding direction with the engagement holes 69b and 69c.

[0117] Thereafter, by moving the exposure head 4 along the upper surface 69U of the lifting duct 69 (rearward direction B shown in Figure 52), the engagement claws 55b and 55c of the exposure head 4 engage with the engagement holes 69b and 69c of the lifting duct 69, respectively, by snap-fit.

[0118] That is, the exposure head 4 is moved in the axial direction relative to the lift duct 69 to engage the engagement claws 55b, 55c with the engagement holes 69b, 69c in an extension direction perpendicular to the protruding direction. In this way, the exposure head 4 is connected to the lift duct 69 in the image forming apparatus 100, and the exposure head 4 becomes one with the lift duct 69. The procedure for removing the exposure head 4 from the lift duct 69 is the reverse of the procedure described above. The structure for replacing and detaching the exposure head will be described in detail later.

[0119] (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 as seen from below.

[0120] The cartridge tray 30 is a support member that supports the drum unit 23 and the developing unit 24, and guides and supports the attachment and detachment operation along the axial direction of the photosensitive drum 2. The cartridge tray 30 supports the rotation shaft 102a of the inner door 102 so that the inner door 102 is rotatable within a predetermined range.

[0121] A cartridge tray 30 is provided for each image forming unit. Each cartridge tray 30 has a developer support member 301 that supports and guides the attachment and detachment operation of the developing unit 24 along the axial direction of the photosensitive drum 2, and a drum support member 302 that supports and guides the attachment and detachment operation of the drum unit 23 along the axial direction of the photosensitive drum 2. In the cartridge tray 30, the developer support member 301 and the drum support member 302 are integrally formed. Note that the cartridge tray 30 is not limited to being provided for each image forming unit.

[0122] The lifting duct 69 is movably disposed between the developing device support member 301 and the drum support member 302 of the cartridge tray 30. The lifting duct 69 has a first engagement portion 69d and a second engagement portion 69e at both longitudinal ends supported by a pivot arm 65 from below between the developing device support member 301 and the drum support member 302. The pivot arm 65, which will be described later, is pivotably provided on the developing device support member 301 of the cartridge tray 30. The exposure head 4 is detachably attached to the lifting duct 69 movably disposed 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 / detachment operation along the axial direction of the photosensitive drum 2.

[0123] (developer support member) The developing device support member 301 is a developing device support member that supports and guides the attachment / detachment operation of the developing unit 24 along the axial direction of the photosensitive drum 2, and is a longitudinal member that extends in the axial direction of the photosensitive drum 2. The developing device support member 301 has a first developing device guide portion 301a, a second developing device guide portion 301b that faces the first developing device guide portion 301a, and a developing device bottom surface portion 301c that is provided between the first developing device guide portion 301a and the second developing device guide portion 301b. The developing device support member 301 has the first developing device guide portion 301a, the second developing device guide portion 301b, and the developing device bottom surface portion 301c that are integrally formed.

[0124] The developing bottom surface portion 301c faces the bottom surface portion 24D of the frame of the developing unit 24 across a space, 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 at one end of the developing bottom surface portion 301c in a width direction perpendicular to the longitudinal direction, and is provided between the lift-up duct 69 and the developing unit 24 so as to separate the lift-up duct 69 and the developing unit 24. The second developing guide portion 301b is provided at the other end of the developing bottom surface portion 301c in the width 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 against the frame of the developing unit 24, and guide the developing unit 24 along the longitudinal direction as it is inserted or removed in the longitudinal direction.

[0125] The first developing guide portion 301a has a facing portion 301d facing the first inclined surface 69L1 of the lifting / lowering duct 69. The facing portion 301d has a first tray inclined surface that is inclined in the same manner as the first inclined surface 69L1 of the lifting / lowering duct 69.

[0126] The first developing guide portion 301a has a partition portion 301e downstream of the opposing portion 301d in the movement direction of the lifting duct 69 from the retracted position toward the exposure position. The partition portion 301e is provided between the exposure head 4 and the developing unit 24 so as to separate the exposure head 4 located at the exposure position shown in FIG. 22 from the developing unit 24. The partition portion 301e is the end (upper end) of the first developing guide portion 301a on the developing sleeve side.

[0127] 2, 8, and 22, the developer support member 301 (cartridge tray 30) is disposed directly below the developing unit 24. The upper surface of the developer support member 301 (cartridge tray 30) and the bottom surface of the developing unit 24 form a duct, which is a closed space, and in addition to guiding the attachment and detachment operation of the developing unit, it also functions as an intermediate path for developer cooling airflow, which will be described later.

[0128] As will be described later, an opening at one longitudinal end (front side) of a duct (closed space) formed by the upper surface of the cartridge tray 30 (developer support member 301) and the upper surface of the developing unit 24 communicates with an opening 41a of a front duct 41 that takes in air from outside the apparatus via an opening 102c of the inner door 102. The opening at the other longitudinal end (rear side) of the duct communicates with an opening 42a of a rear duct 42 that exhausts air to the outside of the apparatus. The duct between the developing unit 24 and the developer support member 301 forms a single closed space that communicates with the front duct 41 and the rear duct 42 (see Figure 34).

[0129] (Drum support member) The drum support member 302 is a photosensitive member support member that supports and guides the attachment / detachment operation of the drum unit 23 along the axial direction of the photosensitive drum, and is a longitudinal member extending in the axial direction of the photosensitive 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 has the first drum guide portion 302a, the second drum guide portion 302b, and the drum bottom portion 302c integrally formed.

[0130] The drum bottom surface portion 302c faces the bottom surface portion 23D of the frame of the drum unit 23 and is provided along the longitudinal direction, which is the axial direction of the photosensitive drum 2. The first drum guide portion 302a is provided at one end of the drum bottom surface portion 302c in a width direction perpendicular to the longitudinal direction, and is provided between the lifting duct 69 and the drum unit 23 so as to separate them. The second drum guide portion 302b is provided at the other end of the drum bottom surface portion 302c in the width direction and is provided so as to face the first drum guide portion 302a. The first drum guide portion 302a and the second drum guide portion 302b each abut against the frame of the drum unit 23 and guide the drum unit 23 along the longitudinal direction as it is inserted or removed in the longitudinal direction.

[0131] The first drum guide portion 302a has a facing portion 302d that faces the second inclined surface 69R1 of the lifting / lowering duct 69. The facing portion 302d has a second tray inclined surface that is inclined in the same manner as the second inclined surface 69R1 of the lifting / lowering duct 69.

[0132] (Relationship between cartridge tray and lifting duct) Here, the relationship between the cartridge tray 30 and the lifting duct 69 will be described.

[0133] The lifting duct 69 is movably disposed between the first developing guide portion 301a and the first drum guide portion 302a on the cartridge tray 30, and is moved between an exposure position shown in Fig. 24 and a retracted position shown in Fig. 25 by the rotation of a pivot arm 65 described later. In other words, the first developing guide portion 301a and the first drum guide portion 302a of the cartridge tray 30 function as guide members that guide the lifting duct 69 in its movement direction.

[0134] Furthermore, when the exposure head 4 is detachably attached to the lift duct 69, the opening 55a of the exposure head 4 and the opening 69a of the lift duct 69 communicate with each other, and the lift duct 69 is integrated with the exposure head 4. The lift duct 69 is separated from the developing unit 24 by the first developing guide portion 301a of the cartridge tray 30, and is separated from the drum unit 23 by the first drum guide portion 302a of the cartridge tray 30. Furthermore, when the lift duct 69 is in the exposure position shown in FIG. 22, the gap between the lift duct 69 and the first developing guide portion 301a is sealed by a seal 72, which is a sealing member described later. Similarly, when the lift duct 69 is in the exposure position shown in FIG. 22, the gap between the lift duct 69 and the first drum guide portion 302a is sealed by a seal 71, which is a sealing member described later.

[0135] In this way, the cartridge tray 30 and the lifting duct 69 arranged between the first developing guide portion 301a and the first drum guide portion 302a of the cartridge tray 30 form a duct which is a closed space communicating with the opening 55a of the exposure head 4.

[0136] (Relationship between the cartridge tray, lifting duct and duct unit) Furthermore, the cartridge tray 30 and the lifting duct 69 have an opening 64 formed on the side facing the duct unit 60, which will be described later, and which communicates with an opening 61 of the duct unit 60.

[0137] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 will be described with reference to FIGS.

[0138] 21, the opening 64 formed by the cartridge tray 30 and the lifting duct 69 is formed by the developing device support member 301, the drum support member 302, and the lifting duct 69 between the developing device support member 301 and the drum support member 302. More specifically, the opening 64 is formed by the developing device guide portion 301a of the developing device support member 301, the drum guide portion 302a of the drum support member 302, and a duct front wall 69F and a duct rear wall 69B of the lifting duct 69 between the developing device guide portion 301a and the drum guide portion 302a.

[0139] In this way, the cartridge tray 30 and the lifting duct 69 form an opening 64 on the side facing the duct unit 60, which is described later, that communicates with the opening 61 of the duct unit 60. When the duct unit 60, which is described later, is attached to 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. This causes the opening 64 formed by the cartridge tray 30 and the lifting duct 69 to communicate with the opening 61 of the duct unit.

[0140] 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 is sealed by a sealing member 207, which will be described later.

[0141] (Relationship between the lift duct ribs and the duct unit) Further, the duct front wall 69F and the duct rear wall 69B, which are ribs of the lift duct 69, will be described in detail.

[0142] As will be described later, of the sealing members 207 provided at 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 opposing first developing guide portion 301a and first drum guide portion 302a of the cartridge tray 30, as shown in Figure 37, to seal the space between them. The first developing guide portion 301a and first drum guide portion 302a of the cartridge tray 30 are arranged on both left and right side surfaces of the lifting duct 69 (see Figure 22).

[0143] Therefore, the left and right ends of the opening of the lift duct 69, i.e., the boundary with the duct unit 60 in the longitudinal direction in the range La shown in Figure 20, is sealed by sealing the gap between the duct unit 60 and the cartridge tray 30 with the sealing member 207. Therefore, the sealed state is always maintained without being affected by the movement of the lift duct 69.

[0144] On the other hand, a different sealing structure is required at the front and rear ends of the opening of the lift-down duct 69, i.e., the boundary between the ranges La and Lc and the boundary between the ranges La and Lm shown in Fig. 20. This is because the boundary between the front and rear ends of the opening of the lift-down duct 69 and the duct unit 60 cannot be sealed like the boundary between the cartridge tray 30 and the duct unit 60.

[0145] In this embodiment, the front and rear ends of the duct unit 60 are sealed with the opening 61 (see FIG. 35) by a duct front wall 69F and a duct rear wall 69B shown in FIG.

[0146] Figures 29 and 30 show cross sections of the exposure head 4, the lift duct 69, and the duct unit 60. The position of the cross sections shown in Figures 29 and 30 is the position as seen from the arrow EE in Figure 37, and the cartridge tray 30 is not shown. Figure 29 is a cross section showing the arrangement of the lift duct 69 when it has been moved to the exposure position. Figure 30 is a cross section showing the arrangement of the lift duct 69 when it has been moved to the retracted position.

[0147] A duct front wall 69F and a duct rear wall 69B of the lifting duct 69 are disposed outside a duct region (range La in FIG. 20 ) in which an opening 69a of the lifting duct 69 is provided, in the axial direction of the photosensitive drum 2. The duct front wall 69F and the duct rear wall 69B protrude toward a duct unit 60 (described later) in the movement direction of the lifting duct 69, and have lengths such that they overlap with the side surfaces of the duct unit 60 (see FIGS. 29 and 30 ). The lengths of the duct front wall 69F and the duct rear wall 69B are such that, when the exposure head 4 is in the exposure position, the duct front wall 69F and the duct rear wall 69B overlap with the side surfaces of a sealing member 207 provided at the opening 61 of the duct unit 60. 29 and in the retracted position shown in Fig. 30, the side surfaces of the duct front wall 69F and the duct rear wall 69B on the opening 69a side come into contact with the longitudinally outer side surfaces of a sealing member 207 provided in an opening 61 of a duct unit 60 described later. In other words, the duct front wall 69F and the duct rear wall 69B have the above-mentioned lengths such that the side surfaces of the opening 69a side come into contact with the longitudinally outer side surfaces of a sealing member 207 provided in an opening 61 of a duct unit 60 described later at the exposed position shown in Fig. 22.

[0148] 29, the side surfaces of the duct front wall 69F and the duct rear wall 69B of the lifting duct 69 form the front and rear end walls of the range La. Furthermore, the gap between the duct front wall 69F and the duct rear wall 69B and the duct unit 60 is sealed by the side surfaces of the sealing member 207 on the top surface of the duct unit 60 coming into contact with the side surfaces of the duct front wall 69F and the duct rear wall 69B.

[0149] In addition, in the retracted position shown in Figure 30, the lifting duct 69 is retracted so that the side of the duct front wall 69F and the side of the duct rear wall 69B overlap the outside of the side of the duct unit 60, and does not interfere with the duct unit 60.

[0150] 28, the duct left wall 69L and the duct right wall 69R of the lift-up duct 69 are shorter in length in the movement direction (UD axis direction) than the duct front wall 69F and the duct rear wall 69B. The duct left wall 69L and the duct right wall 69R of the lift-up duct 69 have a length such that they do not protrude below the cartridge tray 30 when the exposure head 4 is in the retracted position (see FIG. 23).

[0151] In other words, the height in the movement direction of the duct left wall 69L and duct right wall 69R of the lifting duct 69 in range La shown in Fig. 20 is lower than the duct front wall 69F and duct rear wall 69B at both ends outside range La. Fig. 28 is a perspective view showing the exposure head 4 and the lifting duct 69 engaged and integrated. As shown in Fig. 28, the duct left wall 69L (and duct right wall 69R) in range La is configured to be lower in the front-to-rear direction, with the duct front wall 69F and duct rear wall 69B as boundaries.

[0152] This is to prevent the lower ends of the left duct wall 69L and the right duct wall 69R in the range La of the lifting duct 69 from protruding from the cartridge tray 30 and from entering the interior of the duct unit 60, even when the lifting duct 69 is retracted from the photosensitive drum 2.

[0153] Even if the left duct wall 69L and the right duct wall 69R in the range La of the lift duct 69 are not lowered and are configured to extend into the interior of the duct unit 60, sealing is possible. In this case, the third opening 201 and the fourth opening 202 on the top surface of the duct unit 60 must be large enough to allow the retracted lift duct 69 to enter, and further, space is required inside the duct unit 60 to accommodate the retracted lift duct 69. This imposes restrictions on the shape of the duct unit 60. In addition, it imposes restrictions on the assembly order of the duct unit 60. For this reason, it is desirable to make the left duct wall 69L and the right duct wall 69R in the range La of the lift duct 69 lower than the duct front and rear walls so that they do not protrude below the cartridge tray 30 when the exposure head 4 is in the retracted position.

[0154] By configuring in this manner, the lower ends of the duct left wall 69L and the duct right wall 69R do not enter the interior of the duct unit 60 when the exposure head 4 is moved to the retracted position, and do not hinder its movement.

[0155] By configuring it in this way, the lifting duct 69, which moves integrally 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 it and the duct unit 60, thereby reducing toner scattering inside the image forming apparatus.

[0156] 30 , the duct front wall 69F and duct rear wall 69B of the lift duct 69 overlap with the side surfaces that are on the outside of the opening 61 of the duct unit 60. However, the present invention is not limited to this. For example, a configuration may be adopted in which, among the duct left wall 69L, duct right wall 69R, duct front wall 69F, and duct rear wall 69B, only the duct front wall 69F and duct rear wall 69B intrude into the inside of the openings 201 and 202 of the duct unit 60.

[0157] (Developing Stay) The cartridge tray 30 is provided with a developing stay 31 that is slidable 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 viewed from the right.

[0158] The developing stay 31, which is a sliding member, is provided movably relative to the developing support member 301 of the cartridge tray 30. The developing stay 31 is provided on the developing bottom surface portion 301c of the developing support member 301 so as to be movably 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 has a developing pressure piece 32, a developing pressure piece 33, a developing stay link 34, an arm retraction member 68F, and an arm retraction member 68B.

[0159] The developer stay link 34 is fixed to the front end of the developer stay 31, and engages with an inner door 102 pivotally supported on the cartridge tray 30. The developer pressure piece 32 is fixed to one side (front side) in the longitudinal direction of the developer stay 31, and the developer pressure piece 33 is fixed to the other side (rear side) in the longitudinal direction of the developer stay 31. The developer pressure piece 32 and the developer pressure piece 33 are provided in positions facing the developer unit 24.

[0160] When the inner door 102 is open, the link engagement portion 102b that engages with the development stay link 34 is located closer to the rear end (the lower end when the door is open) of the inner door 102 than the rotation shaft 102a. Therefore, as the inner door 102 rotates, the link engagement portion 102b of the inner door 102 moves in the rotation direction along a circular locus whose radius is the distance between the rotation shaft 102a and the link engagement portion 102b. In other words, as the inner door 102 is opened as shown in FIG. 32, the link engagement portion 102b also rotates and moves toward the rear of the apparatus.

[0161] As a result, the developing stay link 34 that engages with the link engaging portion 102b of the inner door 102 slides in the direction of arrow B toward the rear of the device, and the two developing pressure pieces 32, 33 that are integrally formed through the developing stay 31 also slide in the direction of arrow B. This means that the two developing pressure pieces 32, 33 move out of the positions that hold the developing unit 24, as shown in Figure 32. When the developing pressure pieces 32, 33 move out of the holding positions, the developing unit 24 moves in the direction of arrow D, which is the direction in which it retreats from the photosensitive drum 2, due to its own weight.

[0162] From the above explanation, it can be seen that the developing unit 24 is retracted from the photosensitive drum 2 in conjunction with the operation of opening the inner door 102. When closing the inner door 102, the developing unit 24 is moved toward and pressed against the photosensitive drum 2 by going through the reverse procedure of the opening operation.

[0163] In this way, the developing stay 31 is slid back and forth by the developing stay link 34 that engages with the link engaging portion 102b in conjunction with the opening and closing operation of the inner door 102. By sliding back and forth, the developing stay 31 moves the developing unit 24 between a developing position (see FIG. 22) where the developing sleeve 5 approaches the photosensitive drum 2 during development, and a separated position (see FIG. 23) where the developing sleeve 5 is separated from the photosensitive drum 2 during non-development.

[0164] 31, the developing stay 31 slides forward in the direction F in conjunction with the closing of the inner door 102. At this time, the developing unit 24 moves upward (in the direction of arrow U) along the slopes of the developing pressure pieces 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves in a direction approaching the photosensitive drum 2 of the drum unit 23.

[0165] 32, the developing stay 31 slides in the rear direction B in conjunction with the opening of the inner door 102. At this time, the developing unit 24 moves downward (arrow D) along the slopes of the developing pressure pieces 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves in a direction away from the photosensitive drum 2 of the drum unit 23, and the developing sleeve 5 is spaced further away from the photosensitive drum 2 than during development.

[0166] Furthermore, the developing stay 31 has an arm retraction member 68F and an arm retraction member 68B for rotating a rotating arm 65, which is a rotating member described below. The arm retraction member 68F and the arm retraction member 68B are configured integrally with the developing stay 31. The arm retraction member 68F is fixed to one longitudinal side (the front side of the apparatus) of the developing stay 31, and is provided on the surface opposite the developing pressure piece 32. The arm retraction member 68B is fixed to the other longitudinal side (the rear side of the apparatus) of the developing stay 31, and is provided on the surface opposite the developing pressure piece 33. When the developing stay 31 slides forward and backward in conjunction with the opening and closing of the inner door 102, the arm retraction member 68F and the arm retraction member 68B are moved in the same direction, thereby rotating the rotating arm 65.

[0167] The developing stay 31 disengages from the pivot arm 65 by moving in one axial direction. This causes the pivot arm 65 to pivot in one direction, moving the exposure head 4 together with the lifting duct 69 to the exposure position. On the other hand, the developing stay 31 engages with the pivot arm 65 by moving in the other axial direction. This causes the pivot arm 65 to pivot in the other direction, moving the exposure head 4 together with the lifting duct 69 to the retracted position.

[0168] (rotating arm) 24 and 25, a rotating arm 65, which is a rotating member, is rotatably provided on the developing device 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. In addition, an engagement boss 66, which is the other end of the rotating arm 65 in the left-right direction, supports engagement portions 69d, 69e, which are both ends of a region outside an opening 69a of the lifting duct 69 in the axial direction.

[0169] Specifically, one end of the pivot arm 65 in the left-right direction pivots around a pivot shaft 30a integrally provided on the cartridge tray 30. The pivot shaft 30a is centered on an axis parallel to the movement direction of the development stay 31 and is integrally provided on the back surface of the development bottom portion 301c of the development support member 301, opposite the surface facing the development unit 24. The movement direction of the development stay 31 can be described as the axial direction of the rotation center of the photosensitive drum 2, or the longitudinal direction of the drum unit 23, development unit 24, and exposure head 4. This is the condition that allows the pivot arm 65 to be arranged most compactly relative to the width dimension of the cartridge tray 30 shown in Figure 25, taking into account the operation of arm retraction members 68F and 68B, which will be described later. This also allows the pivot arm 65 to have the least impact on the arrangement and operation of surrounding components.

[0170] The pivot 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 pivot arm 65 opposite the pivot shaft 30a. The pivot arm 65 supports both ends of the exposure head 4 in the longitudinal direction outside the opening 55a from below. In other words, the pivot arm 65 supports both longitudinal ends of the lifting duct 69, which supports the exposure head 4 along the longitudinal direction, from below in an area (area Lm in FIG. 20) outside the duct area (area La in FIG. 20) of the exposure head 4. Specifically, the pivot arm 65 supports from below the bottom surfaces of the first engagement portion 69d and the second engagement portion 69e at both longitudinal ends of the lifting duct 69, respectively, with the engagement boss 66 provided at its tip.

[0171] The rotating arm 65 presses upward the bottom surfaces of the first engagement portion 69d and the second engagement portion 69e at both ends of the lift-up duct 69 in the longitudinal direction 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 FIG. 24, the exposure head 4 is disposed close to the photosensitive drum 2, and this state 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 lift-up duct 69. This pressing force is ensured by a predetermined spring pressure of the arm pressure spring 67.

[0172] In this way, the rotary arm 65 does not press the exposure head 4 directly, but presses the lifting duct 69 that supports the exposure head 4 .

[0173] The rotating arm 65, together with the arm pressure spring 67 and a rotating shaft 102a provided on the cartridge tray 30, constitutes a movement mechanism (retraction mechanism) that raises and lowers the lifting duct 69. That is, the movement mechanism for moving (raising and lowering) the lifting duct 69 includes the rotating shaft 102a, the rotating arm 65 which is a rotating member that rotates around the rotating shaft 102a, and the arm pressure spring 67 which is a biasing member that biases the rotating arm 65.

[0174] The rotating arm 65 rotates about the rotating shaft 30a in response to the sliding movement of the developing stay 31, and moves the exposure head 4 to the exposure position (see FIG. 24) or the retracted position (see FIG. 25). That is, in conjunction with the opening and closing of the inner door 102, the rotating arm 65 rotates in one direction to move the exposure head 4 to the exposure position where the photosensitive drum 2 is exposed, and rotates in the other direction to move the exposure head 4 to the retracted position where it is retracted from the exposure position.

[0175] Specifically, as shown in FIG. 32, the developing stay 31 slides in the rear 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 rear direction B, engage with the rotating arm 65. This rotates the rotating arm 65, and the rotating arm 65 is pressed downward against the force of the arm pressure spring 67 (see FIG. 25). This rotation of the rotating arm 65 causes the engagement boss 66 provided at the tip of the rotating arm 65 to press down the engagement ribs 69d1 and 69e1 provided at the lower ends of the engagement portions 69d and 69e of the lift-up duct 69, thereby retracting the exposure head 4 integrated with the lift-up duct 69 from the photosensitive drum 2. In other words, the exposure head 4 is moved from the exposure position to the retracted position.

[0176] The retraction of the pivot arm 65 is achieved by inserting wedge-shaped arm retraction members 68F and 68B between the upper surface of the pivot arm 65 and the lower surface of the cartridge tray 30 at a position close to the pivot shaft 30a.

[0177] 31, in conjunction with the operation of closing the inner door 102, the developing stay 31 slides forward in the direction F. At this time, the arm retraction members 68F and 68B move forward in the direction F, and the arm retraction members 68F and 68B are disengaged from the pivoting arm 65. This causes the pivoting arm 65 to rotate, and the pivoting arm 65 is pushed upward by the force of the arm pressure spring 67 (see FIG. 24). This rotation of the pivoting arm 65 causes the engagement boss 66 provided at the tip of the pivoting 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 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.

[0178] In this way, 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 around an axis parallel to the axial direction. The engaging boss 66 at the other end of the rotating arm 65 supports engaging portions 69d, 69e which are both ends of the area 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 FIG. 20.

[0179] Furthermore, the rotating arm 65 that constitutes the movement mechanism that moves the exposure head 4 between the exposure position and the retracted position is provided outside the duct area of ​​the exposure head (area La shown in FIG. 20). Therefore, it does not obstruct the air being sent from below the exposure head 4 to the duct area, and air can be blown directly onto the back surface of the substrate 50 of the exposure head 4. This makes it possible to more effectively cool the substrate 50 including the light-emitting elements of the exposure head 4.

[0180] 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. Therefore, the air that cools the exposure head 4, which is introduced to the rear surface of the substrate 50, does not leak to the side of the developing unit 24 adjacent to the exposure head 4, thereby reducing toner scattering inside the device.

[0181] The operation of the pivot arm 65 that moves the exposure head 4 to the exposure position or the retracted position is powered by the sliding movement of the development stay 31 that retracts the development unit 24, but the power may also be obtained via another member linked to the inner door 102.

[0182] (Sealing of exposure head) The sealing performance of the exposure head 4 will be described using Figure 33. Like Figure 22, Figure 33 is a cross-sectional view taken along the line XX in Figure 20. Figure 33 does not show the drum unit 23 or the developing unit 24, but is a cross-sectional view of the exposure head 4, the lifting duct 69, and the cartridge tray 30 as seen from the front.

[0183] As can be seen from FIG. 33, the exposure head 4 is attached to the lifting duct 69, which forms a cooling duct for the exposure head.

[0184] As described above, the housing support member 55 of the exposure head 4 is provided with engagement claws 55b1, 55b2 for engaging with the lifting duct 69. Meanwhile, the lifting duct 69 is provided with engagement holes 69b, 69c for engaging with the engagement claws 55b1, 55b2 on an upper surface 69U facing the exposure head 4. Based on this configuration, the exposure head 4 can be engaged with the lifting duct 69 and integrated together in accordance with the procedure for replacing and attaching / detaching the exposure head 4, which will be described later.

[0185] There is a small gap between the engaging claws 55b1, 55b2 of the exposure head 4 and the lifting duct 69.

[0186] This gap exists in the vertical direction in FIG. 59, that is, in the direction of arrow D shown in FIG. 49, and is a necessary gap from the viewpoint of ease of assembly and part precision.

[0187] First, from the viewpoint of ease of assembly, if this gap does not exist, it will create resistance to the sliding movement in the direction of arrow B shown in Figure 52, causing the sliding movement to get stuck midway, which may prevent the slide from reaching the intended position shown in Figure 57.

[0188] Next, from the viewpoint of part precision, the housing support member 55 and the lift duct 69 are long and narrow in the direction of movement (front-rear direction) as a whole, and a certain amount of warping is unavoidable in the part manufacturing process.

[0189] For example, if the housing support member 55 has a warp in the longitudinal center that is 0.5 mm convex toward the lift duct 69 compared to both ends, unless the aforementioned gap is 0.5 mm or more, the engagement claws 55b1 and 55b2 will not engage with the edges of the engagement holes 69b and 69c in the first place.

[0190] From the above explanation, it can be seen that a certain amount of gap is necessary to absorb warpage of the components and to prevent resistance from occurring when the exposure head 4 is attached to the lifting duct 69.

[0191] However, this gap is undesirable from the perspective of a duct that sends air to cool the exposure head 4, and there is a risk that toner may be scattered inside the device due to blowing or suction from the gap. Therefore, in order to reduce the above-mentioned risk, the size of the gap must be minimized.

[0192] One possible solution is to place a seal such as a foam sealant in the gap. Specifically, a seal is attached to the exposure head or the lifting duct that forms the gap. However, there is a possibility that the seal may be turned up or peeled off due to the sliding movement of the exposure head, as indicated by arrow B in Figure 52. Furthermore, since the seal is located near the photosensitive drum 2 and the developing sleeve 5, and considering the possibility that fragments of the seal may adhere to these, it is desirable to take measures other than attaching a seal.

[0193] Therefore, in this embodiment, in order to reduce this gap, the configuration is as shown in Figure 28. Figure 28 is a perspective view showing the lifting duct 69 in a state where it is engaged with the exposure head 4, and the rotating arm 65 in a state where it is engaged with the lifting duct 69.

[0194] As described above, the pivot arm 65, which functions as the movement mechanism for the exposure head 4, presses upward the bottom surfaces of the first and second engagement portions 69d and 69e at both longitudinal ends of the lift-up duct 69 by the force of the arm pressure spring 67, which is a biasing member. Here, if the top surface 69U, on which the exposure head 4 is attached, is defined as a first surface, the bottom surfaces of the first and second engagement portions 69d and 69e of the lift-up duct 69 are second surfaces that are arranged opposite this first surface in the movement direction of the lift-up duct 69. When the pivot arm 65 rotates in one direction, the other end presses upward the bottom surfaces of the first and second engagement portions 69d and 69e at both ends of the lift-up duct 69, thereby moving the exposure head 4 together with the lift-up duct 69 to the exposure position and maintaining the exposure position of the exposure head 4 relative to the photosensitive drum 2. This pressure is ensured by the predetermined spring pressure of the arm pressure spring 67, as described above.

[0195] In this way, the rotating arm 65 does not directly press the exposure head 4 but presses the lifting duct 69 that supports the exposure head 4 .

[0196] Furthermore, the pivot arm 65 biases the lifting duct 69 toward the photosensitive drum 2 with a predetermined spring pressure from an arm pressure spring 67, which is a biasing member. In other words, the pivot arm 65 biases the lifting duct 69 toward the housing support member 55 with a predetermined spring pressure from the arm pressure spring 67.

[0197] Here, the spring pressure of the arm pressure spring 67 is set to a sufficiently strong value, so that the pivot arm 65 biases the lift 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 lift duct 69.

[0198] Furthermore, even if the housing support member 55 of the exposure head 4 or the upper surface 69U of the lifting duct 69 that engages with this housing support member 55 has a certain amount of warping due to the process of manufacturing the parts, the posture of both can be corrected by the biasing force of the arm pressure spring 67, thereby reducing the gap between the parts caused by the warping.

[0199] By configuring it in this manner, the exposure head 4 can be easily attached and detached to and from the lifting duct 69, and gaps between the exposure head 4 and the lifting duct 69 due to assembly and component precision can be reduced, thereby reducing toner scattering inside the image forming device.

[0200] (Duct unit) The image forming apparatus 100 also includes 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 as seen from above. Figure 36 is a perspective view of the duct unit as seen from below. Figure 37 is a cross-sectional view of the intake side of the exposure cooling airflow, taken along line Y3-Y3 in Figure 34. Figure 39 is a cross-sectional view of the exhaust side of the exposure cooling airflow, taken along line Y4-Y4 in Figure 34.

[0201] The duct unit 60 is an exposure cooling unit that communicates with an 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 .

[0202] Duct unit 60 has an intake fan 62 and an intake duct 205 for sending air from outside the image forming apparatus to each exposure head 4. Duct unit 60 has 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. Duct unit 60 integrally comprises intake fan 62, exhaust fan 63, intake duct 205, and exhaust duct 206, and is detachably attached to the main body of image forming apparatus 100 directly below cartridge tray 30.

[0203] Duct unit 60 has intake duct 205 and exhaust duct 206 provided separately from intake duct 205. In other words, duct unit 60 has intake duct 205 as a first duct and exhaust duct 206 as a second duct provided separately from the first duct.

[0204] Duct unit 60 has an intake port 203 and an exhaust port 204 on the same side (left side) of image forming apparatus 100, with intake fan 62 disposed in intake port 203 and exhaust fan 63 disposed in exhaust port 204. In this embodiment, as shown in Fig. 34, intake fan 62 disposed near the front of image forming apparatus 100 functions as an intake fan that takes in air from outside the apparatus, and exhaust fan 63 disposed near the rear functions as an exhaust fan that exhausts air to the outside of the apparatus.

[0205] An exterior cover forming the exterior of the left side of the image forming apparatus has louvers (not shown) formed as openings (first opening and second opening) at positions facing the respective fans 62 and 63. The louvers formed in the exterior cover communicate with intake port 203 and exhaust port 204 in which fans 62 and 63 are respectively arranged. Air is taken in by intake fan 62 and exhausted by exhaust fan 63 through the louvers formed in the exterior cover forming the exterior of the left side of the image forming apparatus.

[0206] 35 and 37, duct unit 60 has third openings 201 (Y, M, C, K) for each exposure head on its top surface near the front of image forming apparatus 100. Air intake port 203 and the openings 201 (Y, M, C, K) for each exposure head are connected by air intake duct 205. Duct unit 60 is configured to discharge air (fresh air) from outside the image forming apparatus, which is taken in through air intake port 203 by air intake fan 62, from each opening 201.

[0207] 35 and 39, the duct unit 60 has a fourth opening 202 (Y, M, C, K) for each exposure head on its top surface and toward the rear of the image forming apparatus 100. The exhaust port 204 and the opening 202 for each exposure head are connected by an exhaust duct 206. The duct unit 60 is configured so that air taken in through each opening 202 by an exhaust fan 63 is discharged from the exhaust port 204 to the outside of the image forming apparatus.

[0208] In this embodiment, for convenience of part molding, the duct unit 60 is configured with two parts, an upper frame 60a and a lower frame 60b, which are divided into upper and lower parts, as shown in Figures 35 and 36. Here, the duct unit 60 is configured such that the outer edges of the upper frame 60a and the lower frame 60b in the front-to-rear direction are secured together with a snap fit, and also secured together with a snap fit at a position straddling the intake duct 205 and the exhaust duct 206. Here, securing together with a snap fit at a position straddling the intake duct 205 and the exhaust duct 206 means that the portion of the upper frame 60a between the intake duct 205 and the exhaust duct 206 is secured together with a snap fit at a portion of the lower frame 60b facing the portion 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 by snap fitting in this manner, air leakage from gaps between the dividing surfaces of the intake duct 205 and the exhaust duct 206 is suppressed.

[0209] As shown in Figure 35, the duct unit 60 has openings 61 (Y, M, C, K) on its top surface. The openings 61 of the duct unit 60 include a third opening 201 provided near the front of the device and a fourth opening 202 provided near the rear of the device. The openings 61 (Y, M, C, K) of the duct unit 60 are provided to correspond to the exposure heads 4 of each color, respectively.

[0210] That is, opening 60Y of duct unit 60 includes opening 201Y provided near the front of the device and opening 202Y provided near the rear of the device. Opening 60M of duct unit 60 includes opening 201M provided near the front of the device and opening 202M provided near the rear of the device. Opening 60C of duct unit 60 includes opening 201C provided near the front of the device and opening 202C provided near the rear of the device. Opening 60K of duct unit 60 includes opening 201K provided near the front of the device and opening 202K provided near the rear of the device.

[0211] The opening 61 of the duct unit 60 is provided at a position opposite to the opening 64 formed by the lifting duct 69 and the cartridge tray 30, and is pressed against the opening 64 to communicate with it, forming a closed space.

[0212] (Configuration of sealing member of duct unit) As explained above, the exposure cooling airflow flows from the third opening 201 of the duct unit 60 to the first opening 73 communicating with it as shown in Fig. 37, and from the fourth opening 202 to the second opening 74 communicating with it as shown in Fig. 39. That is, 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 elevator duct 69, which include the first opening 73 and the second opening 74 communicating with it. Therefore, in order to prevent toner scattering due to airflow leakage and a decrease in cooling efficiency due to airflow pressure loss, it is desirable to seal the gaps between the openings.

[0213] 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.

[0214] 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 rubber or sponge made of urethane or silicone. Figure 21 is a schematic diagram of the cartridge tray 30 and the lift-up duct 69 as seen from below. In Figure 21, the opening 64 formed by the cartridge tray 30 and the lift-up duct 69 is indicated by hatching.

[0215] 21, the opening 64 formed by the cartridge tray 30 and the lifting duct 69 is formed by the developing device support member 301, the drum support member 302, and the lifting duct 69 between the developing device support member 301 and the drum support member 302. More specifically, the opening 64 is formed by the developing device guide portion 301a of the developing device support member 301, the drum guide portion 302a of the drum support member 302, and a duct front wall 69F and a duct rear wall 69B of the lifting duct 69 between the developing device guide portion 301a and the drum guide portion 302a.

[0216] On the upper surface of the duct unit 60, a sealing member 207 is provided so as to surround the 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.

[0217] 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 sealing member 207 and the developing guide portion 301a of the developing device 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 is provided across from the opening 201 on one side (front side) in the front-rear direction to the opening 202 on the other side (rear side).

[0218] 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 sealing member 207 and 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 across from the opening 201 on one side (front side) in the front-rear direction to the opening 202 on the other side (rear side).

[0219] When pressed by the duct unit 60, 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 at its side with the side of the duct front wall 69F of the lift-down duct 69. The side of the duct front wall 69F of the lift-down duct 69 that comes into contact with the sealing member 207 is the surface that faces the side of the duct rear wall 69B in the front-to-rear direction.

[0220] When pressed by the duct unit 60, the sealing member 207 provided on the upper surface of the other short side of the opening 61 of the duct unit 60 comes into contact at its side with the duct rear wall 69B of the lift-down duct 69. The side of the duct rear wall 69B of the lift-down duct 69 that comes into contact with the sealing member 207 is the surface that faces the side of the duct front wall 69F in the front-rear direction.

[0221] The reason why the side surfaces of the duct front wall 69F and the duct rear wall 69B are configured to contact the side surfaces of the sealing member 207 is as follows: The lifting duct 69 is moved between the exposure position shown in FIG. 22 and the retracted position shown in FIG. 23 by the rotation of the rotating arm 65, and this movement must not be obstructed by the duct unit 60.

[0222] An opening 64 formed by this cartridge tray 30 and the lift duct 69 communicates with an opening 55a of the exposure head 4 that is integrally supported by the lift duct 69. When the duct unit 60 is attached to the image forming apparatus 100, an opening 61 of the duct unit is pressed against the opening 64 formed by the cartridge tray 30 and the lift duct 69, and the opening 64 and the opening 61 communicate with each other. As a result, a duct that is a single closed space is formed from the duct unit 60 through the cartridge tray 30 and the lift duct 69 to the exposure head 4.

[0223] In this way, the sealing member 207 is pressed between the opening 61 of the duct unit 60 and the developing guide portion 301a and the drum guide portion 302a, and the side surfaces of the sealing member 207 are brought into close contact with the side surfaces of the duct front wall 69F and the duct rear wall 69B to seal the gap. In other words, the gap between the opening 61 of the duct unit 60 and the opening 64 formed by the cartridge tray 30 and the lift-up duct 69 is sealed by the sealing member 207. This prevents toner from scattering due to airflow leakage and a decrease in cooling efficiency due to airflow pressure loss.

[0224] (Assembly and removal of duct units) The configuration for assembling and removing duct unit 60 to image forming apparatus 100 will be described with reference to Figures 2, 35, 37, 38, 21, 40, 41, and 36. Figure 37 is a cross-sectional view showing a state in which duct unit 60 is assembled to image forming apparatus 100. Figure 40 is a cross-sectional view showing a state immediately before duct unit 60 is assembled to image forming apparatus 100 or immediately after it has been removed. Figure 41 is a partial enlarged view of Figures 37 and 40. Figure 36 is a perspective view of duct unit 60 as viewed from the right front lower direction.

[0225] Duct unit 60 is inserted from one side (here, the left side) of image forming apparatus 100 in the left-right direction to the other side, and when positioned, is moved from below to above by guides (guide portion 103, support portion 104) within the apparatus. At this time, opening 61 of duct unit 60 is pressed against (engaged with) opening 64 formed by cartridge tray 30 and lifting duct 69, and an air passage is formed that connects opening 64 and opening 61. This will be explained below with reference to the drawings.

[0226] As described above, the duct unit 60 presses and tightly contacts the sealing member 207 between the cartridge tray 30 and the lifting duct 69 to seal the gap, thereby preventing toner scattering due to airflow leakage and a decrease in cooling efficiency due to airflow pressure loss. For this reason, it is desirable that the duct unit 60 be assembled so that it rises from approximately below the components assembled to the image forming apparatus 100, such as the cartridge tray 30.

[0227] 2, the sheet cassette 12 is disposed below the duct unit 60, and simply assembling the duct unit 60 from below to the image forming apparatus 100 is difficult 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 immediately before the assembly position when inserted from the side.

[0228] Here, it is desirable to assemble the duct unit 60 from the left side of the image forming apparatus 100. This is because rollers and guides related to the transport of the recording paper P are located on the right side of the image forming apparatus 100, and assembling the duct unit 60 requires removing the rollers and guides related to the transport, so assembly from the right side is avoided.

[0229] As shown in FIGS. 37, 41(a), and 41(b), a supported portion 209 on the underside 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 portion of a metal plate 100C that bridges between a front side panel 100F and a rear side panel 100B that constitute a part of the frame (housing) of the image forming apparatus. A total of four supported portions 209 are provided, two on each of the right and left ends of the duct unit 60 in the front-to-rear direction. This corrects any tilt or distortion of the duct unit 60 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.

[0230] 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 .

[0231] As shown in FIGS. 37, 41(a), and 41(b), the duct unit 60 is fixed to the image forming apparatus 100 by fastening portions 210 of the duct unit 60 to fastening portions 105 of the metal plate 100C with fastening members 211. As shown in FIG. 35, the fastening portions 210 are provided at two positions on the left end of the duct unit 60, and are located near the intake fan 62 and the exhaust fan 63. The fastening portions 105 are provided at two positions on the left end of the metal plate 100C, and are located opposite the fastening portions 210 in the insertion / removal direction of the duct unit 60. This firmly fixes the intake fan 62 and the exhaust fan 63 to the image forming apparatus 100, making it possible to suppress the generation of rattle noise due to vibration and image defects such as streaks caused by the vibration being transmitted to the drum 2, etc.

[0232] 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 or the lifting duct 69. Therefore, the sealing member 207 of the duct unit 60 does not come into sliding contact with the image forming apparatus 100, allowing the duct unit 60 to be easily assembled to or removed from the image forming apparatus 100. At this time, the guided portion 208 of the duct unit 60 is in contact with the guiding portion 103 of the image forming apparatus 100. In this embodiment, the guiding portion 103 is formed by a curved surface that is continuous with the supporting portion 104, and the guided portion 208 is formed by a surface that is continuous with the supported portion 209 and is inclined with respect to the assembly direction of the duct unit 60. As a result, by assembling the duct unit 60 from the left side of the image forming apparatus 100 to the right, it will naturally trace a trajectory upward to the upper right, and transition to the assembled state shown in Figures 37, 41(a), and 41(b).

[0233] When duct unit 60, which is an exposure / cooling unit, is inserted into image forming apparatus 100, it moves upward and to the right while being guided by guided portion 208 having an inclined portion inclined along the insertion direction. As a result, sealing member 207 is compressed and tightly fitted between cartridge tray 30 and lifting duct 69, sealing the gap between opening 64 and opening 61.

[0234] (Duct unit intake and exhaust ports) Next, the intake fan 62 and the exhaust fan 63 of the duct unit 60 will be described in more detail.

[0235] The exposure cooling air flow is formed as a path separate from the path of the developer cooling air flow, as can be seen from the overall image of the developer cooling air flow shown in Figure 34 described above, and from Figures 22 and 37. Therefore, toner leaking from the developing unit 24 does not get mixed into the exposure cooling air flow, reducing the risk of toner scattering inside the device.

[0236] The air flow is made compact by arranging the intake port 203 and exhaust port 204 of the exposure cooling air flow on the same side of the image forming apparatus main body. Furthermore, by arranging the intake port 203 and exhaust port 204 of the exposure cooling air flow on a different surface from the intake port 101a and exhaust port of the development cooling air flow, it is possible to minimize mutual influence with the development cooling air flow.

[0237] For example, in this embodiment, the exhaust port for the development cooling airflow is located on the back of the apparatus body, while the intake port 203 for the exposure cooling airflow is located on the left side of the apparatus body. This means that the exposure cooling airflow hardly takes in any of the exhaust heat from image formation during development, and vice versa.

[0238] Furthermore, even if the temperature rise conditions for the development unit 24 and the exposure head 4 differ due to the image or paper feed mode, the exposure cooling means and the development cooling means have separate cooling paths and fans, making it possible to perform optimal cooling for each, and allowing for efficient control with a high degree of freedom in airflow control.

[0239] (Duct unit fan configuration) Here, the arrangement of the intake fan 62 and the exhaust fan 63 will be described in detail with reference to FIG.

[0240] Figure 42 is a cross-sectional view of the duct unit as seen from above the image forming apparatus, as indicated by the arrows FF in Figures 37 and 39. Figure 42 shows in detail the arrangement of intake fan 62 and exhaust fan 63, which were simply shown in Figure 34.

[0241] In FIG. 42, intake fan 62 is disposed at an angle θF relative to the direction perpendicular to the left side surface of image forming apparatus 100, i.e., the longitudinal direction of intake duct 205 and exhaust duct 206. Similarly, exhaust fan 63 is disposed at an angle θR relative to the longitudinal directions of intake duct 205 and exhaust duct 206. As a result, the intake direction of intake fan 62 is from one end side of substrate 50 in the longitudinal direction toward the center side in the longitudinal direction, and the exhaust direction of exhaust fan 63 is from the center side of substrate 50 in the longitudinal direction toward the other end side in the longitudinal direction. As shown by the arrows in FIG. 42, the angles θF and θR are such that the intake angle of intake fan 62 and the exhaust angle of exhaust fan 63 are in opposite directions (upward and downward) relative to the horizontal. Therefore, the intake of fresh air by the intake fan 62 is less likely to take in the heat contained in the exhaust air from the exhaust fan 63, which can be said to contribute to suppressing a decrease in cooling efficiency due to the circulation of exposure cooling airflow.

[0242] 42, the angles θF and θR are set to be relative angles such that the axes are diagonally upward and diagonally downward, but they may also be set to be relative angles such that the axes are diagonally left and diagonally right. Furthermore, a combination of these may also be used. That is, it is preferable to set the relative angles so that the central axis of the intake and the central axis of the exhaust do not intersect outside the image forming apparatus 100 and so that the axes of the intake and the exhaust become increasingly distant from each other as they move away from the image forming apparatus 100.

[0243] It can be seen that by attaching a fan to the duct unit 60 as described above, it is possible to reduce toner scattering inside the image forming device and provide a highly efficient and flexible cooling means for the LED exposure device.

[0244] (Developing unit cooling configuration) Next, the cooling configuration of the developing unit 24 will be described with reference to Figure 34. Figure 34 is a cross-sectional view of the image forming apparatus taken along the line AA in Figure 2. In Figure 34, the flow of air for cooling the developing unit 24 is indicated by a dashed line. The air flow indicated by the dashed line in Figure 34 is also referred to as a developer cooling air flow.

[0245] As described above, the developing unit 24 contains the screw 7, which rotates at high speed, and the toner, which circulates at high speed. This operation generates frictional heat in the bearing of the screw 7 and in the toner, and this frictional heat is stored in the developing unit 24, causing the temperature to rise. When image formation is complete, the developing unit 24 stops storing heat and gradually cools down, but while image formation continues, heat is stored as much as the heat capacity of the developing unit 24 allows, causing the temperature to rise. Because toner has the property of easily melting when exposed to heat, if the temperature of the developing unit 24 rises above a certain temperature, the toner will fuse inside the developing unit 24, causing poor coating on the developing sleeve 5 and distorting the toner image, resulting in a defective image.

[0246] Therefore, a cooling mechanism for the developing unit 24 is required to prevent the temperature of the developing unit 24 from rising above a certain temperature.

[0247] The image forming apparatus 100 has a fan 40 and a front duct 41 for sending air from outside the apparatus to each developing unit 24. The image forming apparatus 100 has 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 units 24 and the cartridge tray 30.

[0248] The duct formed in the axial direction of the photosensitive drum between the developing unit 24 and the cartridge tray 30 is disposed between a front duct 41 disposed on the front side of the apparatus and a rear duct 42 disposed on the rear side of the apparatus. One end of the duct formed in the axial direction of the photosensitive drum between the developing unit 24 and the cartridge tray 30 on the front side of the apparatus communicates with the front duct 41, and the other end of the axial direction on the rear side of the apparatus communicates with the rear duct 42, forming one closed space.

[0249] The fan 40 is located on the right side of the front of the image forming apparatus 100 body and draws in air from outside the apparatus through an air intake 101a located on the right side of the front cover 101. 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 opposite openings 102c of the inner doors 102 of each cartridge tray 30 in the axial direction of the photosensitive drums, and are connected to each other when the front cover 101 is closed. The openings 102c of each inner door 102 are located corresponding to openings at one end of the longitudinal direction of the closed space formed between the developing unit 24 and the developing device support member 301, and are connected to each other when the inner doors 102 are closed.

[0250] The rear duct 42 has openings 42a at positions corresponding to the respective developing units 24. The openings 42a of the rear duct 42 are provided in positions corresponding to the openings on the other end side in the longitudinal direction of the closed space formed between the developing units 24 and the developing device support member 301 in the axial direction of the photosensitive drum, and are in communication with each other.

[0251] In this way, the duct, which is a closed space formed between the developing unit 24 and the cartridge tray 30, forms part of a single duct, which is 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, and the front duct 41 and the rear duct 42 that communicate with it, form a first cooling duct, which is a single closed space that serves as a flow path for the developer-cooling airflow.

[0252] The first cooling duct forms a closed space that serves as a flow path for a developer-cooling airflow (air current) that cools the developing unit 24. In other words, the first cooling duct is a developer-cooling means that cools the developing unit, which is the developing means. However, the first cooling duct, which is the developer-cooling means, only needs to be partially formed by the duct, which is the closed space formed between the developing unit 24 and the cartridge tray 30, and other configurations are not limited to those described above.

[0253] Each developing unit 24 is cooled by the developer cooling airflow (indicated by the dashed dotted line in FIG. 34) that flows through the aforementioned single closed space.

[0254] The developer cooling airflow indicated by the dashed line in FIG. 34 is generated by the fan 40 disposed on the front right side of the image forming apparatus and the first cooling duct, which is the single closed space described above.

[0255] When the fan 40 rotates, air outside the device is drawn in through the intake port 101a of the front cover 101 provided on the right side of the image forming device 100, and is sent to the developing unit 24, which is the object 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.

[0256] The air sent to the developing unit 24 is taken in from the front opening in the front-to-rear 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 from the rear opening in the front-to-rear direction.

[0257] The air exhausted from the rear side in the front-to-rear 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, passes through the toner filter 43 together, and is then exhausted from the rear of the device to the outside.

[0258] Here, the toner filter 43 will be described. The toner filter 43 is located in the rear duct 42, just before the exhaust port at the rear of the device. Because the developer cooling air flow passes around the developing unit 24, it is inevitable that a small amount of toner will be drawn into the air flow. Therefore, it is desirable to locate the toner filter 43 just before the exhaust port for the developer cooling air flow so that even a small amount of toner is not discharged outside the device.

[0259] In general, airflow cooling is mainly achieved by using inexpensive fans to generate airflow, and the same is true for airflows other than those for development cooling.

[0260] (Cooling structure of exposure head) Next, the cooling configuration of the exposure head 4 will be described with reference to Figure 34. In Figure 34, the dashed lines indicate the flow of air for cooling the exposure head 4. The air flow shown by the dashed lines in Figure 34 is also referred to as exposure cooling air flow.

[0261] The exposure head 4 dissipates heat according to the amount of light emitted by the LEDs (light-emitting elements) 51, and because it is located in close proximity to the development unit 24, which uses heat-sensitive toner, a cooling means is necessary. In particular, when the image formation process is repeated frequently, i.e., when used in a highly productive device, or when continuously outputting high-density images, the light emission time is long and the amount of light emission is large. Therefore, the amount of heat generated by the LEDs 51 and the circuit on the board 50 on which they are mounted also increases.

[0262] As a countermeasure to this, for example, the housing 54 of the exposure head 4 is used as a heat sink, making it easier for the exposure head 4 to dissipate heat and less likely to accumulate heat. However, even in such a case, it is conceivable that the exposure head 4 may not be cooled in time, causing heat accumulation and increasing the amount of heat dissipated to the surroundings. As a result, the toner around the developing sleeve 5 of the developing unit 24 and some of the circulating toner inside the developing unit 24 may fuse together, affecting the toner coat layer on the surface of the developing sleeve 5 and potentially resulting in poor images.

[0263] Even if a structure for cooling the developing unit 24 is provided, it is easy to imagine that the heat stored due to the light emission of the LED 51 will prevail in the area of ​​the developing unit 24 close to the exposure head 4. Therefore, it is desirable to provide a cooling structure for the exposure head 4 (exposure cooling airflow) for cooling the exposure head 4 and dissipating heat to the outside of the device, separate from the cooling structure for the developing unit 24 (development cooling airflow), thereby suppressing the amount of heat dissipated around the exposure head 4.

[0264] 8, the developing unit 24 and the developing sleeve 5 of the developing unit 24 are disposed adjacent to the exposure head 4. The surface of the developing sleeve 5 is coated with toner, and due to its structure, toner adheres to the vicinity of the bearing portions at both ends of the sleeve, and also adheres to the periphery of 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 high-speed rotation of the developing sleeve 5 and screw 7 increases the internal pressure of the developing unit 24, which can cause toner to be ejected to the outside through gaps in the developing unit 24.

[0265] Therefore, it is desirable that the cooling configuration of the exposure head 4 is configured so that this toner is not caught in or mixed in. In other words, when configuring an exposure cooling airflow separate from the development cooling airflow, it is desirable that the configuration is such that the toner around the development unit 24 adjacent to the exposure head 4 is not caught in or mixed in.

[0266] The image forming apparatus 100 has an exposure head 4, a lifting duct 69, a cartridge tray 30, and a duct unit 60. The exposure head 4 is attached to the lifting duct 69 arranged in the image forming apparatus 100 and is integrated with the lifting duct 69. When the exposure head 4 is attached to the lifting duct 69, an opening 55a of a housing support member 55 of the exposure head 4 communicates with an opening 69a of the lifting duct 69. The lifting duct 69 is arranged between a first developing guide portion 301a and a first drum guide portion 302a of the cartridge tray 30, and together with the cartridge tray 30, forms a duct that communicates between the exposure head 4 and the duct unit 60. The duct unit 60 is attached to the image forming apparatus 100. When the duct unit 60 is attached to 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 .

[0267] In this way, the housing support member 55 of the exposure head 4, the lift duct 69, the cartridge tray 30, and the duct unit 60 form a second cooling duct, which is a single continuous closed space. Each exposure head 4 is cooled by an exposure cooling air flow (indicated by a broken line in FIG. 34 ) that flows through the single closed space formed by the housing support member 55, the lift duct 69 that communicates with it, and the duct unit 60 that communicates with the lift duct and the cartridge tray 30.

[0268] The second cooling duct, which is a closed space serving as a flow path for the exposure cooling airflow and shown by the dashed line in Figure 34, is configured separately from the first cooling duct, which is a closed space serving as a flow path for the development cooling airflow and shown by the dotted line in Figure 34.

[0269] The first cooling duct, through which the airflow for cooling the developing unit 24 flows, and the second cooling duct, through which the airflow for cooling the exposure head 4 flows, are separated by the first developing guide portion 301a of the developing support member 301 and the lifting duct 69. In other words, the first developing guide portion 301a of the developing support member 301 and the lifting duct 69 separate the first cooling duct, through which the airflow for cooling the developing unit 24 flows, and the second cooling duct, through which the airflow for cooling the exposure head 4 flows, between the exposure head 4 and the developing unit 24.

[0270] The second cooling duct forms a closed space that serves as a flow path for 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 the exposure means. However, the second cooling duct, which is the exposure cooling means, is not limited to the above-mentioned configuration as long as a closed space separate from the first cooling duct is formed by the lifting duct 69, which is the exposure support member, the cartridge tray 30, which is the support member, and the duct unit 60, which is the exposure cooling unit.

[0271] As described above, the duct unit 60, cartridge tray 30, lift 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 apparatus only through the exterior cover of the apparatus. The exposure cooling airflow path is completed with the shortest possible route, formed by directly drawing air into the duct unit 60 through the louvers of the exterior cover and directly exhausting it from the duct unit 60. Therefore, this configuration makes it unlikely that the intake and exhaust airflow will affect the ambient air inside the apparatus.

[0272] Note that the image forming apparatus 100 has an optional finisher on the paper discharge side, and when the finisher is installed, the finisher covers almost the entire left side of the image forming apparatus 100, which is the area facing the intake fan 62 and exhaust fan 63. In this case, the intake and exhaust air from the intake fan 62 and exhaust fan 63 is directed to the inside of the finisher, which is largely hollow. Therefore, the louvers (not shown) of the exterior cover are positioned to avoid facing the main structures inside the finisher. This makes it possible to minimize the performance degradation of the exposure cooling airflow to a level that does not cause any problems in actual use.

[0273] (Sealing structure using sealing material) Next, using Figures 22 and 23, we will explain the sealing configuration of the first cooling duct, which is a closed space that serves as a flow path for the development cooling airflow, and the second cooling duct, which is provided separately from the first cooling duct and serves as a flow path for the exposure cooling airflow.

[0274] Specifically, we will explain a sealing configuration in which the gap between the cartridge tray 30 and the lifting duct 69 is sealed with 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 with seal 70, which is a sealing member.

[0275] 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, which provides an exposure cooling airflow to the back surface of the substrate 50 on which the LED 51 is mounted through the opening 55a of the housing support member 55.

[0276] The lower surface of the lift duct 69 is open across its entire width, ensuring a maximum amount of airflow for the substrate 50 placed directly above, and providing an advantageous configuration for cooling the exposure head 4.

[0277] Furthermore, here, when the substrate 50 has a shape that extends elongated in the axial direction of the photosensitive drum 2, cooling efficiency is superior when the exposure cooling airflow is made to flow perpendicular to the longitudinal direction of the substrate 50 rather than parallel to the longitudinal direction of the substrate 50. Also in the duct cross section shown in Figure 37, the airflow flowing inside the second cooling duct is configured to flow approximately perpendicular to the longitudinal direction of the substrate 50, which is the object to be cooled. This configuration is advantageous for cooling even in terms of the angle of the exposure cooling airflow.

[0278] Here, in the second cooling duct, the cartridge tray 30 and the lift duct 69 form a portion of the second cooling duct. The gap between the cartridge tray 30 and the lift duct 69 that forms this portion of the duct is sealed with seals 71 and 72, preventing airflow from leaking outside the duct.

[0279] That is, the image forming apparatus 100 is provided with seals 71 and 72 which are sealing members that seal the gap between the cartridge tray 30 and the lifting duct 69 .

[0280] When the exposure head 4 shown in Figure 22 is in the exposure position, the gap between the lifting duct 69 that supports the exposure head 4 as a whole and the developer support member 301 of the cartridge tray 30 is sealed by a seal 72, which is a sealing member.

[0281] 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 seal 71, which is a sealing member.

[0282] The seal 72 is provided on a first inclined surface 69L1 of the duct left wall 69L, which is the side wall of the lifting duct 69 on the developing unit 24 side. As shown in FIGS. 27 and 28 , the seal 72 is provided on the first inclined surface 69L1 of the duct left wall 69L in the longitudinal direction, over a range La from the duct front wall 69F to the duct rear wall 69B. The seal 72 seals the gap between the first inclined surface 69L1 of the duct left wall 69L of the lifting duct 69 and the opposing portion 301d of the first developer guide portion 301a of the developer support member 301, which faces the first inclined surface 69L1, when the exposure head 4 is in the exposure position. Here, a configuration in which the seal 72 is provided on the lifting duct 69 side is illustrated, but the seal 72 may also be provided on the developer support member 301 side.

[0283] The seal 71 is provided on a second inclined surface 69R1 of the duct right 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 duct right wall 69R in the longitudinal direction, over a range La from the duct front wall 69F to the duct rear wall 69B. The seal 71 seals the gap between the second inclined surface 69R1 of the duct right 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, which faces it, when the exposure head 4 is in the exposure position. Although a configuration in which the seal 71 is provided on the lifting duct 69 side is shown as an example here, the seal 71 may also be provided on the drum support member 302 side.

[0284] Figure 24 shows a state in which the exposure head 4 is disposed close to the photosensitive drum 2. That is, the exposure head 4 is disposed at the exposure position relative to the photosensitive drum 2. As described above, this state is maintained by the pivot arm 65 pressing upward against the bottom surfaces of both ends of the lift-up duct 69. This pressing force is ensured by a predetermined spring pressure of the arm pressure spring 67, which is a torsion coil spring. That is, when the exposure head 4 is at the exposure position shown in Figures 22 and 24, the seals 71 and 72 are crushed by the pressing of the lift-up duct 69 against the developing device support member 301 and the pressing of the lift-up duct 69 against the drum support member 302, thereby ensuring the sealing of the gap.

[0285] 25, when the exposure head 4 is to be retracted from the photosensitive drum 2, the starting point is the rotation of the pivot arm 65 in the direction of retraction from the photosensitive drum 2. As a result, the engagement boss 66 provided at the tip of the pivot arm 65 presses down the engagement ribs 69d1, 69e1 arranged at the lower end of the lifting duct 69, causing the exposure head 4 integrated with the lifting duct 69 to be retracted from the photosensitive drum 2.

[0286] As shown in Figures 25 and 23, when the exposure head 4 is in the retracted position, the seals 71 and 72 are separated from the developer support member 301 and the drum support member 302 that they abut, respectively, and the sealing of the gap is released.

[0287] In other words, when the exposure head 4 is moved to the retracted position, the lifting duct 69 is moved in a direction that widens the gap between the developer support member 301 and the drum support member 302 compared to the gap at the exposure position. In other words, when the exposure head 4 is moved to the retracted position, the seals 71 and 72 are moved in a direction that moves the exposure head 4 away from the developer support member 301 and the drum support member 302, thereby separating the seals and releasing the sealing of the gap.

[0288] In this way, at the exposure position of the exposure head 4, the gap between the cartridge tray 30 and the lift duct 69 is sealed over the range La in the longitudinal direction by seals 71 and 72, which are sealing members. This prevents air flowing between the cartridge tray 30 and the lift duct 69 to the exposure head 4 from leaking through the gap into the spaces around the developing unit 24 and the developing sleeve 5. Furthermore, air flowing between the cartridge tray 30 and the lift duct 69 to the exposure head 4 from leaking through the gap into the spaces around the photosensitive drum 2 and the charging roller 3. Therefore, there is little possibility that toner will be mixed into the exposure cooling air flow, which is the flow of air for cooling the exposure head 4, and it is possible to reduce toner scattering inside the image forming apparatus.

[0289] The developer cooling airflow is guided in the front-to-rear direction by a duct formed between the developing unit 24 and the cartridge tray. In the first cooling duct, the duct formed between the cartridge tray 30 and the developing unit 24 forms a part of the first cooling duct. The gap between the cartridge tray 30 and the developing unit 24 that forms this part of the duct is sealed by a seal 70, preventing the developer cooling airflow from leaking in the direction of the developing sleeve 5.

[0290] That is, the image forming apparatus 100 is provided with a seal 70 which is a sealing member that seals the gap between the cartridge tray 30 and the developing unit 24 .

[0291] When the developing unit 24 is in the pressed position shown in Figure 22, the gap between the developing unit 24 and the developing support member 301 that separates the developing unit 24 from the exposure head 4 is sealed by a seal 70, which is a sealing member.

[0292] The seal 70 is provided between the developing unit 24 and the exposure head 4, on the first developing guide portion 301a of the developing support member 301, which separates the developing unit 24 from the exposure head 4. The seal 70 is provided between the frame of the developing unit 24 and the first developing guide portion 301a of the developing support member 301, at a portion that narrows as the developing unit 24 moves toward the development position. Here, the seal 70 is provided at the end (partition portion 301e) of the first developing guide portion 301a of the developing support member 301 on the developing roller side when the developing unit 24 is in the development position. The seal 70 is provided on the surface of the partition portion 301e of the developing support member 301 that faces the frame of the developing unit 24. The seal 70 is provided in the first developing guide portion 301a of the developing support member 301, from one end to the other end in the longitudinal direction. The seal 70 seals the gap between the partition wall portion 301e, which is the end portion of the developing support member 301 on the developing roller side, and the opposing frame of the developing unit 24. Here, a configuration in which the seal 70 is provided on the developing support member 301 side is exemplified, but a configuration in which the seal 70 is provided on the developing unit 24 side is also possible.

[0293] 31, the developing stay 31 slides forward in the direction F in conjunction with the closing of the inner door 102. At this time, the developing unit 24 moves upward (in the direction of arrow U) along the slopes of the developing pressure pieces 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves in a direction approaching the photosensitive drum 2 of the drum unit 23, and the developing sleeve 5 is pressed against the photosensitive drum 2.

[0294] 22 and 24, the developing unit 24 is moved in a direction to narrow the gap between the developing unit 24 and the first developing guide portion 301a of the developing unit support member 301 that separates the developing unit 24 from the exposure head 4. In other words, when the developing unit 24 shown in FIGS. 22 and 24 moves to the developing position, the seal 70 is crushed by moving the developing unit 24 closer to the developing unit support member 301, thereby sealing the gap.

[0295] 32, the developing stay 31 is slid in the rear direction B in conjunction with the opening of the inner door 102. At this time, the developing unit 24 is moved downward (arrow D) along the slopes of the developing pressure pieces 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 is moved to a spaced position farther away from the photosensitive drum 2 of the drum unit 23 than during development.

[0296] 25 and 23, the developing unit 24 is moved in a direction to widen the gap between the developing unit 24 and the first developing guide portion 301a of the developing support member that separates it from the exposure head 4, compared to the gap shown in Fig. 22. That is, in the retracted position of the developing unit 24 shown in Figs. 25 and 23, the seal 70 is moved away from the developing support member 301 in a direction that moves the developing unit 24 away from the developing support member 301, and the seal of the gap is released.

[0297] In this way, when the developing unit 24 is in the developing position, the seal 70 seals the gap between the end (partition wall portion 301e) of the developing support member 301 on the developing sleeve side and the opposing frame of the developing unit 24. This prevents air flowing between the developing unit 24 and the cartridge tray 30 from leaking in the direction of the developing sleeve 5 through the gap.

[0298] As shown by the dashed line in Figure 34, the developer cooling air flow may contain a small amount of toner because it flows around the developer unit 24. Therefore, by blocking the paths between the air flows in this way, toner will not be mixed in from the developer cooling air flow. Considering that the exposure cooling air flow is configured with the shortest path, with the duct directly connecting to the outside of the device and exhausting air, the possibility of toner scattering inside the device can be reduced.

[0299] Although the configuration in which the seals 71, 72, and 73 are separated by moving the lift-up duct 69 and the developing unit 24 in a direction away from the respective target components has been exemplified, the present invention is not limited to this. The seals 71, 72, and 73 can also be released from the sealing of the gap by reducing the pressure applied to the lift-up duct 69 and the developing unit 24 by moving them in a direction away from the respective target components, even if they are not separated.

[0300] In addition, seals 71, 72, and 73, which are sealing members, are made of foam seal material made of rubber sponge material. The dimensions of the seal are such that the thickness of the seal is made larger than the width of the gap mentioned above, and the difference is the amount of compression of the seal, thereby compressing the internal air bubbles and increasing the sealing force.

[0301] The sealing material used for sealing is not limited to foam sealing material, but may also be a rubber sheet material (sheet material) such as a urethane sheet. In this case, a sheet longer than the width of the gap is used, and the edge of the sheet is aligned with the object to be sealed. Unlike foam sealing material, to increase the sealing force, the sheet's length or contact angle can be increased to increase the contact force with the object.

[0302] Whether the seal is made of rubber sponge or rubber sheet material, it must be attached using an adhesive such as double-sided tape. Because the adhesive surface 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 the short direction, the adhesive may peel off, leading to the seal curling, peeling, or falling off. Therefore, when adhering or attaching the seal, it should be configured so that the stress it receives in the short direction is minimized.

[0303] Furthermore, bellows-shaped rubber materials may be considered as a more common sealing material, but since a certain amount of space is required for the bellows to expand and contract, and the ease of assembly is not good, this embodiment does not anticipate its use.

[0304] (Sealing element angle) Here, the seals 71 and 72, which are sealing members, will be described in more detail.

[0305] The seals 71 and 72, which are sealing members, reduce the risk of toner getting mixed into the exposure cooling airflow path and the development cooling airflow path, and reduce toner scattering inside the device. For this reason, the sealing members must be configured to prevent curling, peeling, falling off, etc.

[0306] Here, the movement direction of the exposure head 4 from the retracted position shown in Fig. 25 to the exposure position shown in Fig. 24 is indicated by arrow G in Fig. 23. Stickers 71 and 72 are affixed to the lifting duct 69 at predetermined angles θ1 and θ2, respectively, relative to the direction of arrow G, which is the movement direction of the exposure head 4.

[0307] Specifically, the seal 71 is provided on a second inclined surface 69R1 of a duct right wall 69R, which is the side wall of the lifting duct 69 on the drum unit 23 side. The second inclined surface 69R1 of the duct right wall 69R 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 angle θ1 has been exemplified, but the abutting surface of the seal 71 may also be inclined at angle θ1.

[0308] The seal 72 is provided on a first inclined surface 69L1 of a duct left wall 69L, which is the side wall of the lifting duct 69 on the developing unit 24 side. The first inclined surface 69L1 of the duct left wall 69L 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 angle θ2 has been exemplified, but a configuration in which the contact surface of the seal 72 is inclined at angle θ2 may also be used.

[0309] When the seals 71 and 72 are made of rubber sponge, the sealing force of the gap is determined by the amount of compression of the seal, as described above. Therefore, as long as a predetermined amount of compression of the seal is ensured at the exposure position shown in Figure 24 where the exposure head 4 is close to the photosensitive drum 2, the angle at which the seals 71 and 72 are attached will not affect the sealing of the gap between the lift-up duct 69 and the cartridge tray 30. Also, in Figure 22, the seals 71 and 72 are primarily subjected to a load in a direction that compresses their thickness, and this load will not cause the seals to turn over, peel off, or fall off.

[0310] Next, the load on the seals 71 and 72 due to the movement of the exposure head 4 will be described with reference to FIG.

[0311] The position of the cross section shown in Fig. 23 is the position as viewed from the arrow XX in Fig. 20, as in Fig. 22, and is a cross section of the range La shown in Fig. 20. However, while the exposure head 4 is at the exposure position close to the photosensitive drum 2 in Fig. 22, the exposure head 4 has moved to a retracted position where it has been retracted from the photosensitive drum 2 in Fig. 23. This is the position corresponding to Fig. 25, in which the exposure head 4 has been retracted from the exposure position to the retracted position.

[0312] 23, the seals 71 and 72, including the seal 70, are separated from the members with which they abut, and the gaps are unsealed. In other words, when the exposure head 4 is retracted from the exposure position and the development unit 24 is retracted from the development position, the gaps are unsealed by the seals 71, 72, and 73.

[0313] This is because sealing of the gap is not necessary during the movement of the exposure head 4, but is performed when the exposure head 4 is positioned at the exposure position shown in Figure 22 relative to the photosensitive drum 2 and the image formation process begins.

[0314] 23 (the retracted position), no load is applied to the seals 71 and 72. Therefore, the seals 71 and 72 will not turn over, peel off, or fall off.

[0315] Regarding the load on the seals 71 and 72 during the movement of the exposure head 4, it is sufficient to consider that the seals 71 and 72 are moved in the direction of arrow G from the state shown in FIG.

[0316] The seal 71 is positioned so that 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 facing it, and is not subjected to any load.

[0317] Although the corners of the seal 72 come into contact with the cartridge tray 30 after the seal 72 starts to move, the seal 72 only receives an oblique load on its affixed surface, and the risk of the seal 72 peeling off or turning over can be said to be small. This oblique load on the seal 72 is determined by the affixing angle θ2 of the seal 72; the larger the angle θ2, the smaller the component of force that induces the seal 72 to peel off or turn over. For example, when the angle θ2 is 90°, i.e., when the seal 72 is affixed perpendicular to the movement direction of the exposure head 4 (the direction of arrow G), the seal 72 does not receive any load during the movement of the exposure head 4. Therefore, as in the retracted position state shown in FIG. 34, the seal 72 does not peel off or turn over.

[0318] However, the larger the angles θ1 and θ2, the larger the area required for movement of the seals 71 and 72 due to the movement of the exposure head 4, making it difficult to compactly house the movement mechanism of the exposure head 4. Therefore, the angles θ1 and θ2 must be set within a predetermined range. In this embodiment, the appropriate range for the angles θ1 and θ2 is between 20° and 90° (20°≦θ1≦90°, 20°≦θ2≦90°).

[0319] As a result, the load on the seals 71 and 72 caused by the movement of the exposure head 4 can be minimized. As a result, the seals 71 and 72 do not turn over, peel off, or fall off during the movement of the exposure head 4. Furthermore, the sliding of the seals 71 and 72 does not create resistance to the movement of the exposure head 4 itself. This leads to stable movement of the exposure head.

[0320] By configuring 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 a sealing property that reduces toner scattering into the inside of the device.

[0321] (Cooling control of exposure head and development unit) Next, the cooling control of the exposure head 4 and the cooling control of the development unit 24 will be described.

[0322] 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 detection sensors (not shown) arranged on the circuit boards 50 of each color. As a result, the intake fan 62 and exhaust fan 63 of the duct unit 60 do not rotate all the time, but start rotating when the temperature detected by the temperature detection sensors reaches a predetermined threshold. In this way, by minimizing the operation of the exposure cooling airflow by the intake fan 62 and exhaust fan 63 and keeping the air volume to a minimum, it is possible to reduce toner scattering inside the image forming apparatus 100 from the viewpoint of control.

[0323] Meanwhile, cooling control of the developing unit 24 is performed by controlling the fan 40 provided on the front side of the apparatus based on a detection signal from an internal temperature sensor (not shown) disposed inside the image forming apparatus 100, separate from the temperature detection sensor. In other words, cooling control of the developing unit is performed by controlling the fan 40, which is controlled differently from the intake fan 62 and exhaust fan 63 in the duct unit 60. This allows control to be performed to provide optimal and minimal cooling in response to the elevated temperature of the developing unit 24.

[0324] The temperature rise conditions of the development unit 24 and the exposure head 4 are different. Therefore, as described above, the cooling control of the exposure head 4 and the cooling control of the development unit 24 are performed separately. This allows the operation of the fan and the air volume of the fan to be kept to the minimum required for each cooling control, further reducing toner scattering inside the image forming apparatus 100.

[0325] By configuring in this manner, a cooling means for the exposure head 4 can be provided that prevents toner from scattering inside the image forming device 100, thereby reducing the possibility of image defects and toner adhesion to the user.

[0326] Figure 26 is a cross-sectional view taken along the arrow EE in Figure 37. Note that Figure 26 shows the FFC 58, drum unit 23, and development unit 24, which are not shown in Figure 37.

[0327] In duct unit 60, intake fan 62, which is disposed toward the front of image forming apparatus 100, functions as an intake fan that takes in air from outside the apparatus. Therefore, when intake fan 62 rotates, air is taken into intake duct 205 from outside the apparatus through intake port 203. The air taken in from outside the apparatus flows from left to right of image forming apparatus 100 along intake duct 205, as shown by the dotted line (air flow 310 in duct) in FIG. 37. The air flowing from the left side to the right side of the apparatus inside intake duct 205 branches off from the left side of the apparatus through third openings 201 for each color provided on the top surface of intake duct 205, in this order, through openings 201Y, 201M, 201C, and 201K, as shown in FIG.

[0328] The 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 gap 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 in communication with each other in the vertical direction.

[0329] Here, the first opening 73 is an opening that is connected to the third opening 201 of the duct unit 60 near the front of the device among the openings 64 formed by the cartridge tray 30 and the lifting duct 69.

[0330] That is, the first opening 73 is disposed on one end side of the center in the longitudinal direction of the substrate 50, and faces the third opening 201 when the duct unit 60 is attached.

[0331] Near the front of the image forming apparatus 100, 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 side wall 55L and the right side wall 55R of the housing support member 55. At this time, in the exposure head 4, the air flow 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 (the front side) to the other side (the rear side).

[0332] 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. Therefore, the airflow blown onto the rear surface of the substrate 50 is guided through this duct (for example, from the front side to the rear side in the longitudinal direction of the substrate), and in the process, the substrate 50 is cooled.

[0333] Simultaneously with the intake air, exhaust fan 63 disposed in duct unit 60 toward the rear of image forming apparatus 100 also functions as an exhaust fan that exhausts air from inside duct unit 60 to the outside of the apparatus. Therefore, when exhaust fan 63 rotates, air is taken in through fourth openings 202 (Y, M, C, K) for each color provided in the upper surface of exhaust duct 206. Fourth openings 202 communicate with second openings 74. Therefore, air inside the duct (cooling duct 75) formed by cartridge tray 30 and lift duct 69 is taken in from fourth openings 202 for each color provided in the upper surface of exhaust duct 206 through second openings 74 that communicate vertically.

[0334] Here, the second opening 74 is an opening that is located toward the rear of the device among the openings 64 formed by the cartridge tray 30 and the lifting duct 69, and is connected to the opening 202, which is the fourth opening of the duct unit 60.

[0335] That is, the second opening 74 is disposed on the other end side of the center in the longitudinal direction of the substrate 50, and faces the fourth opening 202 when the duct unit 60 is attached.

[0336] Air is taken 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 an air flow indicated by the dotted line (airflow 311 in the duct) in Fig. 26, is generated in the duct formed by the cartridge tray 30 and the lifting duct 69, and in the exposure head 4 integrally supported by the lifting duct 69, and the board 50 on which the LEDs 51 are mounted is cooled.

[0337] In duct unit 60, the air taken in through fourth opening 202 of exhaust duct 206 merges sequentially through openings 202K, 202C, 202M, and 202Y in this order from the right side of the apparatus inside exhaust duct 206, as shown by the dotted line (airflow in duct 312) in Fig. 39, and flows from the right side of the apparatus to the left side. The air inside the apparatus that has been taken in by exhaust duct 206 is finally exhausted to the outside of the apparatus through exhaust port 204.

[0338] Furthermore, in the duct unit 60, the cross-sectional area of ​​the intake duct 205 is configured to be smaller than the cross-sectional area of ​​the exhaust duct 206. As a result, the exhaust air volume, or the air volume flowing through the exhaust duct 206, is greater than the intake air volume, or the air volume flowing through the intake duct 205. This ensures that the exposure cooling airflow is not leaked to the outside of the cooling duct 75 formed between the cartridge tray 30 and the lift duct 69, and can be reliably exhausted from the exhaust port 204. Furthermore, the above-described configuration prevents the heated air from raising the temperature of the developing unit 24, etc., and suppresses toner scattering.

[0339] In this embodiment, the balance of intake and exhaust air volumes is adjusted by adjusting the cross-sectional areas of intake duct 205 and exhaust duct 206 , but it may also be adjusted by reducing the air volume of intake fan 62 relative to exhaust fan 63 .

[0340] (exposure head positioning) Next, the positioning of the exposure head 4 will be described with reference to FIGS. 26, 43, and 44 to 49. FIG.

[0341] (exposure head positioning pin) First, the positioning pins 45F and 45B of the exposure head 4 will be described.

[0342] The housing 54 of the exposure head 4 is provided with positioning pins 45F and 45B, which are positioning axes. Both the 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. The positioning pins 45F and 45B are fixed to both longitudinal ends of the housing 54. The 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. ​​The 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.

[0343] Locating pin 45F, 45B In order to ensure a high degree of accuracy in the distance between the surface of the photosensitive drum 2 and the light emission surface of the lens array 52 of the exposure head 4, the position of the positioning surface of the shaft tip is adjusted with reference to the housing 54, and the pins are caulked to the housing 54. Note that the method of fixing the positioning pins 45F and 45B to the housing 54 is not limited to this; for example, the metal positioning pins 45F and 45B may be fixed to the metal housing 54 by welding. In this way, in this embodiment, the positioning pins 45F and 45B are integrated with the housing 54.

[0344] 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 movement direction of the lifting duct 69, thereby forming 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 in the direction perpendicular to the axial direction of the photosensitive drum 2 is determined, and the position of the exposure head 4 with respect to the photosensitive drum 2 is also determined.

[0345] Furthermore, positioning pins 45F and 45B fix not only the distance but also the angle of the exposure head 4 relative to the photosensitive drum 2. In the image forming apparatus 100 shown in Fig. 2, the exposure head 4 is arranged so as to point toward the center of the photosensitive drum 2. This arrangement is adopted because, in terms of the mechanism of the LEDs (light-emitting elements) 51 that the exposure head 4 has, it is not necessary to consider the influence of specular reflection on the surface of the photosensitive drum 2.

[0346] Figure 43 is a cross-sectional view showing the relationship between three parts: the photosensitive drum 2, parts of the positioning pins 45F and 45B (tips on the positioning side), and the pivot arm 65. Figure 43 is a cross-sectional view taken along the line YY in Figure 24, in which only the peripheral parts of the above three parts are visualized. Note that the cross-sectional position has been shifted to the center of the positioning pins 45F and 45B.

[0347] Fig. 44 is a perspective view seen from the front surface, 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. Fig. 45 is a perspective view seen from the rear surface, 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.

[0348] In Figures 43 and 44, the optical axis direction of the exposure head 4 is positioned by the front positioning pin 45F (45B) of the exposure head 4 and the front drum bearing 26 of the photosensitive drum 2 butting against each other at the end face of the positioning pin 45F (45B).

[0349] Each drum bearing 26 has a concave-shaped engaging portion 26F, 26B integrally formed at a position facing the corresponding positioning pin 45F, 45B so that the concave-shaped engaging portion 26F, 26B can engage with the tip of the positioning pin 45F, 45B. By machining the diameter of the tip of the positioning pin 45 and the width of the concave portion of the drum bearing 26 with high precision, positioning in a direction perpendicular to the optical axis direction of the exposure head 4 and a direction perpendicular to the axial direction of the photosensitive drum 2 is performed with high precision. In addition, a slope is formed at the entrance of the positioning pin 45F, 45B so that the positioning pins 45F, 45B do not ride up on the edge of the concave portion when engaging with the engaging portion 26F, 26B of the drum bearing 26.

[0350] As shown in FIG. 26, the positioning pins 45F, 45B and the drum bearing 26 are not in contact with each other in the axial direction of the photosensitive drum 2, and are positioned by a positioning member 250, which will be described later.

[0351] Here, the drum bearing 26 refers to a bearing member that supports the front and rear ends (both ends) of the photosensitive drum 2 in the drum unit 23. By increasing the dimensional accuracy at the engagement points of this drum bearing 26, the photosensitive drum 2 is supported on the drum bearing 26 without any gaps. In other words, highly accurate positioning on the drum bearing 26 can be considered to be highly accurate positioning on the photosensitive drum 2. The photosensitive drum 2 is rotationally driven in accordance with the image formation process. Therefore, the positioning pin 45 of the exposure head 4 is positioned relative to the drum bearing 26.

[0352] 43 and 44 show a cross section 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 pin 45B of the exposure head 4 is 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 of the photosensitive drum 2 in the axial direction.

[0353] Also, as shown in Figure 43, the pressing position where the engagement boss 66 of the pivot arm 65 presses the lifting duct 69, the abutment position between the positioning pins 45F, 45B and the engagement portions 26F, 26B of the drum bearing 26, and the center position of the photosensitive drum 2 are arranged on approximately a straight line, as shown by the dotted line.

[0354] With this arrangement, the exposure head 4 is pressed toward the center of the photosensitive drum 2, so no unnecessary rotational moment is applied to the lifting duct 69. This means that there is no component in the pressing force that promotes tilting of the exposure head 4 relative to the photosensitive drum 2, which leads to high positioning accuracy in distance and angle, and stability in repeated attachment and detachment operations.

[0355] 44 and 45, the positioning pins 45F, 45B are supplementarily fitted at their lower peripheral surfaces into the auxiliary fitting portions 30h, 30i of the cartridge tray 30 in a direction perpendicular to the optical axis direction of the exposure head 4 and in a direction perpendicular to the axial direction of the photosensitive drum 2. This ensures stable positioning accuracy in distance and angle, and repeated attachment and detachment operations, even when a slight rotational moment occurs due to the weight, surface properties, dimensional errors, etc. of the parts.

[0356] (exposure head positioning member) Next, the positioning of the exposure head 4 in the axial direction of the photosensitive drum 2 by the positioning member 250 will be described in detail with reference to FIGS.

[0357] Fig. 46 is a perspective view of the positioning member 250 after it has been attached, and Fig. 47 is a perspective view of the positioning member before it has been attached. Fig. 48 is a perspective view showing the shape of the positioning member 250.

[0358] As shown in Figure 46, a positioning member 250 is attached to the front side 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 side of the cartridge tray 30.

[0359] As shown in FIG. 48, the bottom surface of the positioning member 250 is provided with a restricting portion 250a, a biasing portion 250b, a cross-shaped protrusion 250c, an I-shaped protrusion 250d, and a claw portion 250e, which are third engaging portions.

[0360] The outer diameter of the cross-shaped protrusion 250c is approximately equal to the inner diameter of the round hole 30e, and the left-right length of the I-shaped protrusion 250d is approximately equal to the left-right length of the square hole 30f. The position of the positioning member 250 in the front-rear and left-right directions is determined by fitting the respective protrusions 250c, 250d into the holes 30e, 30f.

[0361] The claw portion 250e has a barbed shape, and the barbed shape is caught on the claw engagement portion 30g, thereby determining the position of the positioning member 250 in the up-down direction.

[0362] The third engaging portion, ie, the restricting portion 250a, is a positioning pin. 45F a first contact surface 250a1 that contacts one side of the positioning pin in the axial direction; 45F and a second abutment surface 250a2 that abuts against the other side of the first abutment surface 250a1 in the axial direction. The first abutment surface 250a1 and the second abutment surface 250a2 face each other in the axial direction. The restricting portion 250a has a concave shape that is open on the right side in the left-right direction, and the notch width 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 that is perpendicular to the movement direction (first direction) of the lift duct 69 and the axial direction of the photosensitive drum 2. The restricting portion 250a, which is a third engaging portion, is fitted into the positioning pin 45F, thereby positioning the exposure head 4 in the axial direction of the photosensitive drum 2 relative to the positioning member 250.

[0363] In this way, the position of the exposure head 4 in the axial direction of the photosensitive drum 2 can be precisely determined by the positioning member 250 that is attached after the exposure head 4 is mounted.

[0364] Here, all parts including the positioning member 250, cartridge tray 30, and positioning pin 45F have play between them due to variations in manufacturing. 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, etc.

[0365] To address this issue, in this embodiment, backlash is eliminated by the urging portion 250b and the urging portion 30d. The urging portion 250b extends rightward from the positioning member 250 and has a thin wall in the axial direction of the photosensitive drum 2, making it easy for the urging portion 250b to elastically deform in the axial direction of the photosensitive drum 2. On the other hand, the urging portion 30d protrudes from the upper surface of the cartridge tray 30 and is configured with a rigid shape that prevents deformation in the axial direction of the photosensitive drum 2. The dimensional relationship is such that the tip of the urging portion 250b interferes with (contacts) the urging portion 30d when the positioning member 250 is attached to the cartridge tray 30. The front surface of the tip of the urging portion 250b comes into contact with the back surface of the urging portion 30d, causing the urging portion 250b to elastically deform in the rear direction. As a result, the reaction force urges the positioning member 250 in the rear direction, i.e., from one side to the other in the axial direction of the photosensitive drum 2.

[0366] 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 that is less affected by repeated operations such as attaching and detaching the exposure head 4, and it is possible to achieve even more precise positioning.

[0367] (Replaceable / detachable exposure head configuration) The replacement / detachment configuration of the exposure head 4 will be described in detail using Figure 33 and Figures 49 to 65. Figure 33, like Figure 22, is a cross-sectional view taken along the line XX in Figure 20. Figure 33 does not show the drum unit 23 or the developing unit 24, but is a cross-sectional view of the exposure head 4, the lifting duct 69, and the cartridge tray 30 as seen from the front.

[0368] 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.

[0369] 49 is a right perspective view showing the state immediately before the exposure head 4 is attached to the lifting duct 69, FIG. 50 is a front cross-sectional view, and FIG. 51 is a left perspective view.

[0370] 49 and 51, the drum unit 23, the developing unit 24, and the positioning member 250 are removed from the image forming apparatus. The exposure head 4 can be replaced or removed with the drum unit 23, the developing unit 24, and the positioning member 250 removed. With the photosensitive drum 2 removed, the exposure head 4 can be manually By It is configured so that it can be moved from the retracted position to the exposure position. Therefore, when replacing or removing the exposure head 4, the exposure head 4 is manually moved to the exposure position. At this time, as shown in Figure 50, the FFC 58 connected to the device main body is connected in advance to the FFC connector 57 of the exposure head 4.

[0371] As described above, the housing support member 55 of the exposure head 4 is provided with the engagement claws 55b, 55c for engaging with the lifting duct 69. Meanwhile, the lifting duct 69 is provided with engagement holes 69b, 69c for engaging with the engagement claws 55b, 55c on an upper surface 69U facing the exposure head 4. Based on this configuration, the procedure for engaging the engagement claws 55b, 55c of the exposure head with the engagement holes 69b, 69c of the lifting duct to form a unit is as follows.

[0372] First, as shown in Figures 49 and 51, by moving the exposure head 4 in the direction of arrow D relative to the lift duct 69, the engagement claws 55b and 55c of the exposure head 4 are dropped into the engagement holes 69b and 69c of the lift duct 69, respectively. That is, the engagement claws 55b and 55c of the exposure head are engaged with the engagement holes 69b and 69c in the 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 remaining. At this time, the excess length of the FFC 58 connected to the circuit board of the apparatus main body and the circuit board 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.

[0373] Fig. 52 is a right perspective view of the exposure head 4 placed in the lifting duct 69, Fig. 53 is a front sectional view, and Fig. 54 is a left perspective view. Fig. 55 is a sectional view of the exposure head 4 placed in the lifting duct 69. Fig. 56 is a perspective view of the vicinity of the conductive member when the exposure head 4 is placed in the lifting duct 69.

[0374] 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 engagement claws 55b, 55c are engaged with the engagement holes 69b, 69c in an extension direction perpendicular to the protruding direction. The state at this time is shown in Figures 57 to 61.

[0375] Fig. 57 is a right perspective view of the exposure head 4 attached to the lift-down duct 69, and Fig. 58 is a left perspective view. Fig. 59 is a cross-sectional view taken along the arrows WW in Fig. 33, showing the exposure head 4 attached to the lift-down duct 69. Fig. 60 is an enlarged cross-sectional view of the engaging portion shown in Fig. 59. Fig. 61 is a perspective view of the vicinity of the conductive member when the exposure head 4 is attached to the lift-down duct 69. Fig. 62 is a right cross-sectional view showing the harness opening. Fig. 63 is a right perspective view of the state after the FFC has been processed to remove excess length. Fig. 64 is a front cross-sectional view of the state after the FFC has been processed to remove excess length. Fig. 65 is a front cross-sectional view showing the state of the FFC in the retracted position.

[0376] The engagement claws 55b, 55c of the exposure head 4 are formed to protrude toward the lifting duct 69 and have a generally L-shape that extends in the direction of arrow B, which is the sliding direction of the exposure head 4. Therefore, by sliding in the direction of arrow B, the tips of the generally L-shaped engagement claws 55b, 55c engage with the edges of the engagement holes 69b, 69c. Due to this engagement, the exposure head 4 is attached to the lifting duct 69 and becomes one with the lifting duct 69 at the position shown in Figures 57 to 59.

[0377] In this way, the exposure head 4 is attached by stabilizing its position with the engagement claws 55b, 55c of the exposure head 4 passing through the engagement holes 69b, 69c of the lifting duct 69, and then sliding the exposure head 4. This makes it possible to easily attach the exposure head 4 with an inexpensive configuration.

[0378] (Relationship between engagement claw and engagement hole) 60, the relationship between the engagement claws of the exposure head 4 and the engagement holes of the lifting duct 69 will be described 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 described, but the relationship between the engagement claws 55c of the exposure head 4 and the engagement holes 69c of the lifting duct 69 is also similar.

[0379] As shown in Figure 60, the engaging claw 55b has elasticity, and a recess 55f is provided at the extended tip of the engaging claw 55b. An engaging hole corresponding to the recess 55f 69b The edge of the hole 69f is provided with a protrusion 69f that engages with the recess 55f. 69b The protrusion 69f provided on the edge of the lifting duct 69 is located at a position corresponding to the recess 55f provided on the tip of the engaging claw 55b when the exposure head 4 is at the position where the sliding operation relative to the lifting duct 69 is completed, that is, at the installation completion position.

[0380] Just before the exposure head 4 completes its sliding movement in the direction of arrow K, the tip of the engagement claw 55b interferes with the convex portion 69f, causing the engagement claw 55b to elastically deform, temporarily increasing the sliding force of the exposure head 4 compared to the operating force immediately before the interference. Soon after, the concave portion 55f of the engagement claw 55b reaches the convex portion 69f, and the concave portion 55f and the convex portion 69f engage, reducing the sliding force of the exposure head 4. That is, when the exposure head 4 is moved in the extension direction relative to the lifting duct 69, the engagement claw 55b elastically deforms before the concave portion 55f and the convex portion 69f engage, changing the operating force for moving the exposure head 4 in the extension direction. This sudden increase and decrease in the sliding force of the exposure head 4 provides a clicking sensation that indicates that the sliding operation of the exposure head 4 is complete.

[0381] In this way, the sliding operating force of the exposure head 4 changes due to the elastic deformation of the engagement claw 55b until the recess 55f of the engagement claw 55b and the protrusion 69f of the engagement hole 69b engage, thereby clearly indicating that the exposure head 4 has been installed.

[0382] 44 and 45, the positioning pins 45F, 45B of the exposure head 4 are auxiliary fitted at their lower peripheral surfaces to the auxiliary fitting portions 30h, 30i of the cartridge tray 30. This fitting is performed simultaneously by sliding the exposure head 4 in the direction of arrow B, as shown in FIGS.

[0383] Furthermore, in this embodiment, the ground connection between the housing 54 of the exposure head 4 and the image forming apparatus 100 is also established simultaneously by sliding the exposure head 4 in the direction of arrow B. The housing 54 of the exposure head 4 and the positioning pins 45F and 45B are fixed by crimping, establishing electrical continuity. The ground connection with the image forming apparatus 100 is established when the peripheral surface of the positioning pin 45F of the exposure head 4 contacts a conductive member 251 provided on the cartridge tray 30 of the apparatus, as shown in Figures 56 and 61. The conductive member is electrically conductive. Specifically, the conductive member 251 is made of a thin metal plate. Therefore, sufficient contact pressure is obtained by contact and deformation caused by the sliding movement of the exposure head 4. The conductive member 251 is electrically connected to the metal frame of the image forming apparatus 100 via a harness (not shown), a resistor element for noise elimination, and a circuit board mounted with a capacitor.

[0384] In this way, by sliding, the positioning pin 45F of the exposure head 4 can be electrically connected to the conductive member 251, and the exposure head 4 can be connected to earth. This makes it possible to easily connect the exposure head 4 to earth, etc., and suppress the generation of radiation noise such as electromagnetic waves. In other words, stable earthing characteristics can be obtained simply by sliding the exposure head 4 to attach it to the lifting duct 69.

[0385] (FFC excess length handling) Here, the excess length of the FFC 58 will be described.

[0386] 62 is a right side cross-sectional view showing the harness opening. The harness opening 252 is made up of a first opening forming portion 55g formed in the housing support member 55 constituting the exposure head 4, a second opening forming portion 69g formed in the lifting duct 69 that will be left on the main body side of the image forming apparatus 100 after replacement, and a second opening forming portion 30c formed in the cartridge tray 30.

[0387] In other words, the harness opening 252 is surrounded by a first opening forming portion 55g provided near the connector 57 of the exposure head 4 and second opening forming portions 69g and 30c provided on the apparatus main body near the first opening forming portion 55g. Here, a configuration is exemplified in which the second opening forming portions that constitute the harness opening 253 are provided in the lifting duct 69 and the cartridge tray 30, respectively.

[0388] In this embodiment, the harness opening 252 is formed on the drum unit 23 side, which is a photosensitive unit. This is because the developing unit 24 side is provided with a part of a duct that serves as a flow path for the airflow (developer cooling airflow) for cooling the developing unit 24, 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 developer cooling airflow.

[0389] In this way, by providing the harness opening 252 on the drum unit 23 side arranged near the exposure head 4, it is possible to prevent influence on the air current flowing along the developing unit 24.

[0390] As shown in Figures 52, 53, and 57, when the exposure head 4 is dropped into the lifting duct 69 or when it is attached, the excess length of the FFC 58 protrudes from the harness opening 252 toward the drum support member 302, interfering with the insertion / removal trajectory of the drum unit 23.

[0391] This extra length of the FFC 58 is the slack (extra length) of the FFC 58 formed between the exposure head 4 and the lifting duct 69 when the exposure head 4 is dropped into the lifting duct and when the exposure head 4 is attached.

[0392] In this way, the exposure head 4 can be attached to the image forming apparatus with the excess length of the FFC 58 pulled out from the harness opening 252 formed by the first opening forming portion 55g and the second opening forming portions 69g and 30c.

[0393] After the exposure head 4 is attached to the lifting duct 69, the excess length of the FFC 58 is handled. The FFC 58 has a bent portion 58a that has been bent in advance at one or more places. The excess length of the FFC 58 is stored from the harness opening 252 while being folded along the bent portion 58a.

[0394] The state of the FFC 58 after excess length processing is shown in Figures 63 and 64. Figure 63 is a right perspective view of the FFC 58 after excess length processing. Figure 64 is a front cross-sectional view of the FFC 58 after excess length processing. Figure 64 is a front cross-sectional view of the position of the FFC 58 in a state where the exposure head 4 is brought close to the photosensitive drum 2 by the movement mechanism of the exposure head 4 (hereinafter referred to as the exposure head close state). By bending the FFC 58 multiple times in the optical axis direction and storing it, the excess length of the FFC 58 can be stored in a space-saving manner, particularly on the upper side near the FFC connector 57.

[0395] 64, the length of the FFC 58 from the end on the connection side with the FFC connector 57 to the first bent portion 58a as seen from the 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 reaching the harness opening 252, preventing the FFC 58 from protruding from the harness opening 252.

[0396] Figure 65 is a front cross-sectional view at the position of the FFC 58 in a state in which the exposure head 4 has been retracted from the photosensitive drum 2 by the movement mechanism of the exposure head 4 (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 makes it possible to prevent the FFC 58 from protruding from the harness opening 252 even when the exposure head 4 is moved multiple times between the exposure head close state and the retracted state by the movement mechanism.

[0397] Finally, as shown in FIG. 47, the positioning member 250 is assembled to the cartridge tray 30, thereby completing the installation of the exposure head 4 as shown in FIG.

[0398] Next, the procedure for removing the exposure head 4 will be described with reference to FIGS.

[0399] When removing the exposure head 4, the exposure heads are placed in the close proximity state (FIGS. 52 and 54) in the same manner as when the exposure head 4 was attached, and the procedure is basically the reverse of the attachment procedure.

[0400] First, from the state shown in FIG. 46, the claw portions 250e of the positioning member 250 are deformed to disengage them from the claw engaging portions 30g of the cartridge tray 30, and the positioning member 250 is removed from the cartridge tray 30 as shown in FIG.

[0401] Here, when removing the exposure head 4, unlike when attaching it, there is no need to deal with the excess length of the FFC 58, for example, by pulling out the FFC 58 from the harness opening 252.

[0402] Next, the exposure head 4 is slid in the direction opposite to the direction of arrow B shown in FIG. 52 to release the engagement between the engagement claws 55b, 55c and the engagement holes 69b, 69c, thereby making it possible to separate it from the lifting duct 69.

[0403] Finally, the exposure head 4 is lifted in the direction opposite to the direction of arrow D shown in Figure 49, and the engagement claws 55b, 55c are pulled out of the engagement holes 69b, 69c. At the same time that the exposure head 4 is lifted, the FFC 58, which was folded and stored, expands, making it possible to pull the exposure head 4 out to the outside of the image forming apparatus 100. In this state, the FFC 58 is pulled out of the FFC connector 57, completing the removal of the exposure head 4.

[0404] Other Examples The configuration of the present invention is not limited to the above-described embodiment.

[0405] In the above-described embodiment, a tandem-intermediate transfer type four-color full-color printer has been described as an example, but for example, a direct transfer type in which a toner image is transferred from the photosensitive drum 2 to the recording paper P without using the intermediate transfer belt 9 may be used. Furthermore, the printer may be a single-color monochrome printer, or a full-color printer with five or more colors using special color toner. In that case, a configuration may be used in which a number of exposure heads 4 corresponding to the number of colors are provided.

[0406] In the above-described embodiment, an elastic body such as sponge or rubber made of materials such as urethane or silicone was used as the sealing member 207, but it is also possible to use a resin sheet such as PET, modified PPE, or PE and seal the gaps at each opening by elastically deforming it.

[0407] Furthermore, although the sealing member 207 is configured to be disposed in the duct unit 60, it may be disposed in the cartridge tray 30 or the lifting duct 69, or a configuration in which it is disposed in a plurality of components may be selected.

[0408] Furthermore, although the third opening 201 and the fourth opening 202 of the duct unit 60 are configured to be connected to the opening 64 (first opening 73 and second opening 74) formed by the cartridge tray 30 and the lifting duct 69, the present invention is not limited to this. For example, the opening 64 may be eliminated, and the first opening 73 and the second opening 74 may be provided in the lifting duct 69, so that the third opening 201 and the fourth opening 202 of the duct unit 60 are directly connected to the first opening 73 and the second opening 74, respectively.

[0409] In the above-described embodiment, the duct unit 60 is configured to have one opening including both the third opening 201 and the fourth opening 202, but it may have only one of the openings. In that case, it is sufficient to bring either the first opening 73 or the second opening 74 on the image forming apparatus side into close contact with the third opening 201 or the fourth opening 202 via the sealing member 207. In this case, it is also possible to bring either the first opening 73 or the second opening 74 on the image forming apparatus side into close contact with the third opening 201 or the fourth opening 202, and to extend the other opening to a space where there is no risk of toner scattering.

[0410] Furthermore, in the above-described embodiment, the cooling duct 75 (see FIG. 26) is formed between the duct unit 60 and the cartridge tray 30 or the lifting duct 69, but it does not necessarily have to be formed by the duct unit 60. In that case, the cooling duct 75 may be formed only by the cartridge tray 30 or the lifting duct 69.

[0411] In the above-described embodiment, the intake port 203 is configured to draw in air directly from outside the image forming apparatus 100 and exhaust air directly to the outside of the apparatus from the exhaust port 204, but this configuration is not necessarily required. For example, the intake port 203 may be configured to draw in relatively low-temperature air from a space that does not have a heat source such as the sheet cassette 12. Furthermore, the exhaust port 204 may also be configured to exhaust air to a space inside the image forming apparatus 100 that is not affected by heat.

[0412] Furthermore, the intake fan 62 and the exhaust fan 63 are not necessarily required, and one or both of them may be omitted and the air flow may be circulated by the pressure difference between the exposure cooling air flow and the outside air.

[0413] The up-down direction of the units and parts has been described in accordance with the arrangement of each unit in the cross-sectional view of the image forming apparatus 100 shown in Fig. 2. However, the units may be arranged such that the photosensitive drum 2 is arranged above the intermediate transfer belt 9 and the exposure head 4 is arranged further above that, such as in a top exposure method in which the photosensitive drum 2 is exposed from approximately above. In that case, the up-down directions in the description of the embodiment are all reversed, and the duct unit 60 is configured to descend just before the assembly position.

[0414] Furthermore, although the guiding portion 103 is a curved surface and the guided portion 208 is an inclined surface, this relationship may be reversed, or a combination of curved surfaces or inclined surfaces may be selected.

[0415] Furthermore, in the above-described embodiment, the harness opening 252 is provided on the drum unit 23 side, but this is not limiting and the harness opening 252 may be provided on the developing unit 24 side. By providing the harness opening 252 on the developing unit 24 side, which is disposed near the exposure head, it is possible to prevent the harness opening 252 from affecting the airflow that flows along the drum unit 23.

[0416] In the above-described embodiment, the engaging claws 55b, 55c are provided on the housing support member 55 that constitutes the exposure head 4, but the engaging claws may be provided on components on the image forming apparatus 100 side. In that case, an L-shaped engaging claw may be provided on the lift duct 69, and an engaging hole that engages with the engaging claw may be provided on the housing support member 55.

[0417] Furthermore, in the above-described embodiment, the recess 55f is provided in the housing support member 55 that constitutes the exposure head 4, but the recess may be provided in a component on the image forming apparatus 100 side. In this case, a recess may be provided in the lift duct 69, and a protrusion that engages with the recess may be provided in the housing support member 55.

[0418] In the above-described embodiment, the sliding movement for mounting the exposure head 4 is performed from the front to the rear of the image forming apparatus 100, but it may be configured so that it slides from the rear to the front. In that case, the shapes of the engagement claws and engagement holes may be reversed in the front-to-rear direction.

[0419] In the above-described embodiment, the exposure head 4 is positioned in the axial direction of the photosensitive drum 2 and is grounded using the front positioning pin 45F, but this may also be done using the rear positioning pin 45B. Furthermore, the grounding may also be done using both the front and rear positioning pins 45F and 45B. [Explanation of symbols]

[0420] 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 (photosensitive 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 portion 30d...Biasing part 31...Developing Stay 40...fan 45F, 45B ... Positioning pin (positioning axis) 50...Substrate 51...LED (light emitting element) 52...Lens array 54...Housing (holding member) 55...Housing support member (holding member) 55D...Bottom part (opposing part) 55a...Aperture 55b,55c...Engagement claw 55f...recess 55g ... First opening forming part 57...FFC connector 58...FFC 58a...Bending part 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...Duct rear wall 69F... Duct front wall 69L...Left wall of duct 69L1 ... First inclined surface 69R... Right wall of duct 69R1 ... Second inclined surface 69U...Top part (support part) 69U1 ... First upper surface part 69U2 ... Second upper surface 69a...Aperture 69b,69c...Engagement hole 69d ... First engagement portion 69e ... second engagement portion 69f...Convex part 69g ... Second opening forming part 70, 71, 72 ... Seals 73...First opening 74...Second opening 76…shielding wall 100...Image forming device 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 members 250... Positioning member 250a ...Regulation Department 250a1 ... first contact surface 250a2 ... second contact surface 250b...Biasing part 251 ...Conductive member 252 ...Harness opening 301 ...developer support member 301a ... First developing guide portion 301b ... second developing guide portion 301c...Developing bottom part 301d ... Opposing part 301e...Partition wall part 302 ... Drum support member 302a ... First drum guide part 302b ... Second drum guide part 302c...Drum bottom 302d ... Opposing part

Claims

1. A photoreceptor; an exposure unit disposed adjacent to the photosensitive member and exposing the photosensitive member to light to form a latent image on the photosensitive member; an exposure support member having a support portion for detachably supporting the exposure means, which is moved integrally with the exposure means in a first direction perpendicular to the axial direction of the photosensitive body, and which is moved between an exposure position where the photosensitive body is exposed and a retracted position where the exposure means is retracted from the exposure position; The exposure means a first engaging portion formed at an opposing portion facing the support portion of the exposure support member in the first direction, the first engaging portion protruding toward the exposure support member and extending in an axial direction of the photosensitive element perpendicular to the protruding direction; The exposure support member is a second engaging portion formed on the support portion facing the exposure means at a position corresponding to the first engaging portion and engaging with the first engaging portion; The exposure means is attached to the exposure support member by the exposure means is moved in the first direction relative to the exposure support member to engage the first engaging portion with the second engaging portion in a protruding direction, and then moved in the axial direction to engage the first engaging portion with the second engaging portion in an extending direction perpendicular to the protruding direction, thereby integrating the exposure means with the exposure support member; An image forming apparatus characterized by:

2. A photoreceptor; an exposure unit disposed adjacent to the photosensitive member and exposing the photosensitive member to light to form a latent image on the photosensitive member; an exposure support member having a support portion for detachably supporting the exposure means, which is moved integrally with the exposure means in a first direction perpendicular to the axial direction of the photosensitive body, and which is moved between an exposure position where the photosensitive body is exposed and a retracted position where the exposure means is retracted from the exposure position; The exposure support member is a first engaging portion formed on a support portion of the exposure support member facing the exposure means in the first direction, the first engaging portion protruding toward the exposure means and extending in an axial direction of the photosensitive body perpendicular to the protruding direction; The exposure means a second engaging portion that is formed at a position corresponding to the first engaging portion on an opposing portion that faces the support portion of the exposure support member in the first direction and that engages with the first engaging portion; The exposure means is attached to the exposure support member by the exposure means is moved in the first direction relative to the exposure support member to engage the second engaging portion with the first engaging portion in a protruding direction, and then moved in the axial direction to engage the second engaging portion with the first engaging portion in an extending direction perpendicular to the protruding direction, thereby integrating the exposure means with the exposure support member; An image forming apparatus characterized by:

3. the first engaging portion has elasticity and a recess at a tip end extending in the axial direction of the photosensitive member; the second engaging portion has a protrusion at a position corresponding to the recess and adapted to engage with the recess, when the exposure means is moved in the extension direction relative to the exposure support member, the first engagement portion elastically deforms before the recess and the protrusion are engaged, thereby changing the operating force for moving the exposure means in the extension direction.

3. The image forming apparatus according to claim 1, wherein the first and second ink cartridges are arranged on the first and second ink cartridges.

4. the first engaging portion has elasticity and a protrusion at a tip end extending in the axial direction of the photosensitive member; the second engaging portion has a recess that engages with the protrusion at a position corresponding to the protrusion, when the exposure means is moved in the extension direction relative to the exposure support member, the first engagement portion elastically deforms before the convex portion and the concave portion are engaged with each other, thereby changing the operating force for moving the exposure means in the extension direction.

3. The image forming apparatus according to claim 1, wherein the first and second ink cartridges are arranged on the first and second ink cartridges.

5. a positioning shaft that is fixed to the exposure unit and abuts against the photosensitive member in the first direction to determine a distance between the exposure unit and the photosensitive member in the first direction; a positioning member that is attached to the image forming apparatus and engages with the positioning shaft of the exposure unit engaged with the exposure support member to determine the axial position of the photosensitive body of the exposure unit, The positioning member is a third engaging portion having a first contact surface that contacts one side of the positioning shaft in the axial direction, and a second contact surface that faces the first contact surface in the axial direction and contacts the other side of the positioning shaft in the axial direction, the third engaging portion being formed in a concave shape that is open on one side in a second direction perpendicular to the first direction and the axial direction of the photosensitive member; the third engaging portion is engaged with the positioning shaft to determine the position of the photosensitive member of the exposure means in the axial direction; 5. The image forming apparatus according to claim 1, wherein the first and second ink cartridges are arranged on the first and second sides of the ink cartridge.

6. The positioning member is a biasing portion that contacts the image forming apparatus and elastically deforms in an axial direction of the photosensitive member when the image forming apparatus is attached to the image forming apparatus; The photosensitive member is biased in the axial direction by a reaction force caused by elastic deformation of the biasing portion.

6. The image forming apparatus according to claim 5,

7. a conductive member connected to a ground and having electrical conductivity; the exposure unit has a conductive member having conductivity, the positioning shaft is electrically conductive and fixed to the conductive member; The conductive member is By moving the exposure means in the axial direction relative to the exposure support member, the exposure means comes into contact with the positioning shaft, thereby connecting the exposure means to ground.

7. The image forming apparatus according to claim 5, wherein the image forming apparatus is a recording medium.

8. the exposure means performs exposure using an organic EL; 8. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

Images