Exposure apparatus, method for manufacturing an exposure apparatus, and image forming apparatus

Abstract

To provide an exposure apparatus that achieves both excellent imaging characteristics and high rigidity. [Solution] The exposure apparatus comprises a long substrate assembly having at least a substrate 50 on which light-emitting elements 51 are arranged, a long lens array 52 that focuses light emitted from the light-emitting elements 51 onto the surface of a photoreceptor, and a housing 54 that supports the substrate assembly. The longitudinal ends of the substrate assembly and the housing 54 are bonded at multiple locations by a first adhesive (77a) made of thermosetting resin. The gap between the longitudinal ends of the substrate assembly and the housing 54 is bonded at least a portion of the gap between the multiple first adhesives (77a) by a second adhesive (59a) made of non-thermosetting resin.

Description

TECHNICAL FIELD

[0001] The present invention relates to an exposure apparatus used for exposing a photoreceptor, a method for manufacturing the exposure apparatus, and an image forming apparatus provided with the exposure apparatus.

BACKGROUND ART

[0002] An electrophotographic image forming apparatus forms an electrostatic latent image by selectively exposing the uniformly charged photosensitive layer (surface) of a photoreceptor. An image is formed by developing the electrostatic latent image with a developer. As an exposure apparatus that exposes a photoreceptor, there is an LED exposure apparatus of an LED (Light-Emitting Diode) array system. The LED exposure apparatus is configured to include an elongated printed board on which a plurality of light-emitting chips composed of LED elements are arranged, a lens array, and a housing that accommodates the printed board and the lens array. The printed board and the lens array are positioned in the housing and adhesively fixed thereto with an adhesive.

[0003] Patent Document 1 discloses a configuration in which a printed board is brought into contact with a housing for positioning in a state where the position of the printed board is adjusted in the longitudinal direction and the lateral direction, and is adhesively fixed with an adhesive made of a photocurable resin. Since the printed board after alignment can be quickly fixed using the photocurable resin, the accuracy of the exposure position is ensured while achieving high production efficiency. Patent Document 2 discloses a configuration in which a printed board and a lens array in a housing are fixed in midair at a position that minimizes variation in imaging characteristics on a surface to be irradiated. In this case, the influence of product variation of each component on the imaging characteristics is reduced.

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0004]

PATENT DOCUMENT 1

PATENT DOCUMENT 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In configurations where each component is positioned by contact with the housing, variations in component dimensions can lead to unstable imaging characteristics on the illuminated surface, making it difficult to achieve high printing accuracy. In configurations where each component is fixed in mid-air within the housing, each component is supported only by adhesive, which can lead to a decrease in imaging characteristics on the illuminated surface if deformation occurs due to external forces or thermal stress. Furthermore, using multiple adhesives can lead to sealing defects. Sealing defects can cause developer to enter the housing, potentially resulting in image defects.

[0006] In view of the above-mentioned problems, the main objective of the present invention is to provide an exposure apparatus that achieves both good imaging characteristics and high rigidity. [Means for solving the problem]

[0007] One embodiment of the exposure apparatus of the present invention comprises a long substrate assembly having at least a substrate on which light-emitting elements are arranged, a long lens array for focusing light emitted from the light-emitting elements onto the surface of a photoreceptor, and a housing for supporting the substrate assembly, wherein the longitudinal ends of the substrate assembly and the housing are bonded at multiple locations with a first adhesive made of a thermosetting resin, and the gap between the longitudinal ends of the substrate assembly and the housing is bonded at least a portion of the gap between the multiple locations of the first adhesive with a second adhesive made of a non-thermosetting resin. One embodiment of the present invention relates to a method for manufacturing an exposure apparatus, comprising: a long substrate assembly having at least a substrate on which light-emitting elements are arranged; a long lens array for focusing light emitted from the light-emitting elements onto the surface of a photoreceptor; and a housing for supporting the substrate assembly, wherein the substrate is bonded and fixed to the housing by applying a first adhesive made of a thermosetting resin such that a portion of the first adhesive is elongated; and in the gap between the longitudinal end of the substrate assembly and the housing, a second adhesive made of a non-thermosetting resin is applied starting from the elongated shape of the first adhesive, thereby bonding the portion of the first adhesive to the housing. One embodiment of the image forming apparatus of the present invention is characterized by comprising: a photoreceptor having a photosensitive layer on its surface; a charger for uniformly charging the surface of the photoreceptor; an exposure apparatus for forming an electrostatic latent image by exposing the charged surface of the photoreceptor to light; a developer for developing the electrostatic latent image to form a toner image on the surface of the photoreceptor; a transfer means for transferring the toner image to recording paper; and a fuser for fixing the transferred toner image to the recording paper. [Effects of the Invention]

[0008] According to the present invention, it is possible to achieve both good imaging characteristics and high rigidity. [Brief explanation of the drawing]

[0009] [Figure 1] Perspective view of an image forming apparatus. [Figure 2] A schematic cross-sectional view of an image forming apparatus. [Figure 3] A schematic cross-sectional view of an image forming apparatus. [Figure 4] Perspective view of an image forming apparatus. [Figure 5] A partially enlarged perspective view of an image forming apparatus. [Figure 6] A partially enlarged perspective view of an image forming apparatus. [Figure 7] A partially enlarged perspective view of an image forming apparatus. [Figure 8] Perspective view of the cartridge tray. [Figure 9] A perspective view of the cartridge tray. [Figure 10] A cross-sectional view of the exposure head. [Figure 11] A perspective view of the exposure head. [Figure 12] A perspective view of the exposure head [Figure 13] (a), (b), and (c) are diagrams showing the substrate in the exposure head, and (d) and (e) are diagrams showing the lens array. [Figure 14] A perspective view of the substrate as viewed from the side of the surface on which the LEDs are mounted (substrate front surface). [Figure 15] A perspective view of the substrate as viewed from the side of the surface on which the connector is mounted (substrate back surface). [Figure 16] A perspective view of the exposure head with the substrate assembled to the housing, as viewed from the lower side. [Figure 17] An enlarged view of the connector side of the exposure head in Figure 16. [Figure 18] A perspective view showing the exposure head in a state where the lens array is assembled to the housing in Figure 16. [Figure 19] A perspective view of the cartridge tray. [Figure 20] A bottom view of the cartridge tray and the lifting duct. [Figure 21] A cross-sectional view taken along line X-X in Figure 19. [Figure 22] A cross-sectional view taken along line X-X in Figure 19. [Figure 23] A cross-sectional view taken along line Y-Y in Figure 19. [Figure 24] A cross-sectional view taken along line Y-Y in Figure 19. [Figure 25] A cross-sectional view of the exposure cooling airflow in the direction perpendicular to the optical axis. [Figure 26] A perspective view of the exposure head, the lifting duct, and the rotating arm. [Figure 27] A perspective view of the exposure head, the lifting duct, and the rotating arm. [Figure 28] A side view of the developing station. [Figure 29] A side view of the developing station. [Figure 30] A cross-sectional view taken along line X-X in Figure 19. [Figure 31] Cross-sectional view AA in Figure 2. [Figure 32] Cross-sectional view of the photosensitive drum, exposure head, and rotating arm. [Figure 33] A cross-sectional perspective view showing the positioning of the photosensitive drum and exposure head on the front side. [Figure 34] A cross-sectional perspective view showing the positioning of the photosensitive drum and exposure head on the back side. [Figure 35] Right-side perspective view with the exposure head removed from the lifting duct. [Figure 36] Front cross-sectional view with the exposure head removed from the lifting duct. [Figure 37] Left side perspective view with the exposure head removed from the lifting duct. [Figure 38] Right-side perspective view showing the exposure head placed in the lifting duct. [Figure 39] Front cross-sectional view showing the exposure head placed in the lifting duct. [Figure 40] Left side perspective view showing the exposure head placed in the lifting duct. [Figure 41] Cross-sectional view showing the exposure head placed in the lifting duct. [Figure 42] A perspective view of the vicinity of the conductive member with the exposure head placed in the lifting duct. [Figure 43] Right-side perspective view showing the exposure head attached to the lifting duct. [Figure 44] Left side perspective view showing the exposure head attached to the lifting duct. [Figure 45] Cross-sectional view showing the exposure head attached to the lifting duct. [Figure 46] Figure 45 shows an enlarged cross-sectional view of the engagement portion. [Figure 47] Right-side perspective view after FFC excess length processing. [Figure 48] Front cross-sectional view of the FFC after excess length processing. [Figure 49] A front cross-sectional view showing the state of the FFC in the retracted position. [Figure 50] A view of the exposure head from below before the application of the sealing material. [Figure 51]A perspective view of the exposure head from below before the application of the sealing material. [Figure 52] Top view of the exposure head before sealing material application. [Figure 53] Top perspective view of the exposure head before sealing material application. [Figure 54] Bottom view of the exposure head after coating with sealing material. [Figure 55] A perspective view of the exposure head from below after the sealing material has been applied. [Figure 56] Top view of the exposure head after the sealing material has been applied. [Figure 57] Top perspective view of the exposure head after coating with sealing material. [Figure 58] A perspective view of the exposure head from below during the application of the fifth adhesive. [Figure 59] A perspective view of the exposure head from below during the application of the first adhesive. [Figure 60] A perspective view of the lower surface of the exposure head during the application of the second adhesive. [Figure 61] Front view of the exposure head during adhesive application. [Figure 62] A perspective view of the lower surface of the exposure head during the application of the sixth adhesive. [Figure 63] A perspective view of the exposure head from below during the application of the third adhesive. [Figure 64] A perspective view of the exposure head from below during the application of the fourth adhesive. [Figure 65] Front view of the exposure head during adhesive application. [Figure 66] (a), (b), and (c) are conceptual diagrams of the first and third adhesive application processes. [Figure 67] (a), (b), and (c) are conceptual diagrams of the second and fourth adhesive application processes. [Figure 68] (a) and (b) are conceptual diagrams showing the occurrence of coating defects. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present invention will be described below with reference to the attached drawings. Note that the dimensions, materials, shapes, and relative arrangements of the components described below are not intended to limit the scope of this invention to those specific components unless otherwise stated.

[0011] (Image forming apparatus) Figure 1 is a perspective view of the image forming apparatus of this embodiment. Figures 2 and 3 are internal configuration diagrams of the image forming apparatus. The image forming apparatus 100 illustrated in Figures 1 to 3 is a copier equipped with a reading device, but it may also be in other forms such as a printer without a reading device. Furthermore, although the image forming apparatus 100 of this embodiment is described as a color image forming apparatus equipped with multiple photoreceptors, it is not limited to this, and may also be a color image forming apparatus equipped with one photoreceptor or an image forming apparatus that forms monochrome images.

[0012] The image forming apparatus 100 includes four image forming units 1Y, 1M, 1C, and 1K that form toner images of yellow (Y), magenta (M), cyan (C), and black (K). Each image forming unit 1Y, 1M, 1C, and 1K has a photosensitive drum 2Y, 2M, 2C, and 2K, which is an example of a photosensitive material. The photosensitive material may be composed of an endless belt instead of a drum. Each image forming unit 1Y, 1M, 1C, and 1K is equipped with charging rollers 3Y, 3M, 3C, and 3K, respectively, as chargers for charging the surface having a charged layer of the photosensitive material 2Y, 2M, 2C, and 2K. Each image forming unit 1Y, 1M, 1C, and 1K is equipped with exposure heads 4Y, 4M, 4C, and 4K, respectively, as exposure devices for exposing the photosensitive material 2Y, 2M, 2C, and 2K. The exposure heads 4Y, 4M, 4C, and 4K of this embodiment are composed of multiple light-emitting elements arranged in a linear fashion. The light-emitting elements are, for example, LEDs. The image forming units 1Y, 1M, 1C, and 1K each include developing units 24Y, 24M, 24C, and 24K, which are developing units that develop the electrostatic latent image formed on the surface of the photoreceptors 2Y, 2M, 2C, and 2K, respectively.

[0013] The letters Y, M, C, and K at the end of the code for each part represent yellow, magenta, cyan, and black, respectively. Hereafter, if it is not necessary to distinguish the colors in the explanation, the letters Y, M, C, and K at the end of the code will be omitted. Similarly, for parts provided for other colors, if it is not necessary to distinguish the colors in the explanation, the letters Y, M, C, and K at the end of the code will be omitted.

[0014] In this embodiment, the image forming apparatus 100 employs a so-called "bottom exposure method," in which the exposure head 4 is positioned below the photosensitive drum 2 and exposes the photosensitive drum 2 from below. The following description will proceed on the premise of an image forming apparatus employing the bottom exposure method. However, the image forming apparatus 100 may also employ a "top exposure method," in which the photosensitive drum 2 is exposed from above.

[0015] 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 6Y, 6M, 6C, and 6K that sequentially transfer the toner image formed on the photosensitive drum 2 to the intermediate transfer belt 9. The intermediate transfer belt 9 is located above the image forming unit 1. The intermediate transfer belt 9 is wrapped around the secondary transfer roller 10. The image forming apparatus 100 of this embodiment employs an intermediate transfer method using the intermediate transfer belt 9, but is not limited to this, and may also employ a direct transfer method in which the toner image is directly transferred from the photosensitive drum 2 to the recording paper.

[0016] The image forming apparatus 100 includes a secondary transfer roller 16 that transfers the toner image on the intermediate transfer belt 9 to the recording paper P, and a fuser 19 that fixes the secondary transferred image to the recording paper P. The secondary transfer roller 16 forms a secondary transfer section T2 between itself and the secondary transfer inner roller 10. Above the intermediate transfer belt 9, toner bottles 22Y, 22M, 22C, and 22K, which contain replenishment toner for each color, are detachably provided to the image forming apparatus 100. The developing unit 24 receives timely and appropriate amounts of toner from the toner bottles 22 corresponding to the colors by a toner replenishment mechanism (not shown).

[0017] The image forming apparatus 100 includes a feeding unit 11 for feeding recording paper P. The feeding unit 11 has sheet cassettes 12a and 12b, feeding rollers 13a and 13b, and a registration roller 15. The sheet cassettes 12a and 12b are located at the bottom of the image forming unit 1. The recording paper P contained in the sheet cassettes 12a and 12b is fed one sheet at a time by the feeding rollers 13a and 13b and transported to the secondary transfer unit T2 at a predetermined timing by the registration roller 15.

[0018] The image forming process using the image forming apparatus 100 with the above configuration will now be described. The charging roller 3Y uniformly charges the surface of the photosensitive drum 2Y. The exposure head 4Y emits light to expose the surface of the photosensitive drum 2Y that has been charged by the charging roller 3Y. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 2Y. The developing unit 24Y develops the electrostatic latent image formed on the photosensitive drum 2Y with a yellow developer (toner). As a result, a yellow toner image is formed on the surface of the photosensitive drum 2Y. 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.

[0019] In this way, a yellow toner image is formed and transferred to the intermediate transfer belt 9. Magenta, cyan, and black toner images are also formed using a similar image formation process and transferred to the intermediate transfer belt 9, with each color's toner image, including yellow, superimposed on the others.

[0020] The toner images of each color transferred onto the intermediate transfer belt 9 are transported by the intermediate transfer belt 9 to the secondary transfer section T2. ​​The toner images transported to the secondary transfer section T2 are transferred collectively to the recording paper P transported from the feeding section 11 by the secondary transfer roller 16. The recording paper P on which the toner images have been transferred is transported to the fuser 19. The fuser 19 fixes the toner images to the recording paper P using heat and pressure. The recording paper P that has been fixed by the fuser 19 is discharged by the discharge roller 20 into the discharge tray 21 located above the toner bottle 22.

[0021] The image forming apparatus 100 of this embodiment has a configuration in which the drum unit 23, which includes the photosensitive drum 2, and the developing unit 24 are replaceable. The drum unit 23 is a unit that integrates the photosensitive drum 2, the charging roller 3, and a cleaning device (not shown). An example of its configuration will be explained using Figures 4, 5, 6, 7, 8, and 9. Figures 4 and 5 are perspective views showing the schematic structure around the drum unit 23 and the developing unit 24. Figure 6 shows how the drum unit 23 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus body. Figure 7 shows how the developing unit 24 is inserted into and removed from the image forming apparatus 100 from the outside of the apparatus body.

[0022] A drum unit 23 is attached to the image forming apparatus 100. The drum unit 23 is a cartridge that is replaced by a user or maintenance worker. The drum unit 23 rotatably supports the photosensitive drum 2. Specifically, the photosensitive drum 2 is rotatably supported by the frame of the drum unit 23. The drum unit 23 may also be configured without a charging roller 3 or a cleaning device.

[0023] The image forming apparatus 100 is equipped with a developing unit 24, which is separate from the drum unit 23. The developing unit 24 comprises a developing sleeve 5, which serves as a developing agent carrier for holding the developing agent (toner), and a screw 7 that agitates the developing agent and supplies it to the developing sleeve 5 (see Figures 2 and 3). The developing unit 24 is a cartridge in which the developing sleeve 5 and the screw 7 are integrated, and as shown in Figures 5 and 7, it can be removed from the main body of the image forming apparatus 100 and replaced by an operator.

[0024] Inside the developing unit 24, toner is circulated and transported at high speed by the screw 7. The rotation speed of the screw 7 is relatively very high compared to the rotation speed of the developing sleeve 5 and the photosensitive drum 2, ensuring that the toner coating on the developing sleeve 5 is even and uniform.

[0025] The image forming apparatus 100 is equipped with a cartridge tray 30 for each image forming unit 1 (see Figures 8 and 9). The drum unit 23 and the developing unit 24 are supported by the cartridge tray 30 corresponding to the color. The drum unit 23 and the developing unit 24, supported by the cartridge tray 30, are guided in the axial direction of the photosensitive drum 2 (drum axis direction) and are inserted into and removed from the main body of the image forming apparatus 100.

[0026] As shown in Figure 31, the image forming apparatus 100 includes a front plate 100F made of sheet metal and a rear plate 100B also made of sheet metal. Figure 31 is a cross-sectional view of AA in Figure 2. The front plate 100F is a side wall provided on the front side of the image forming apparatus 100. The front plate 100F constitutes part of the housing of the apparatus body at the front side of the apparatus body of the image forming apparatus 100. The rear plate 100B is a side wall provided on the rear side of the image forming apparatus 100. The rear plate 100B constitutes part of the housing of the apparatus body at the rear side of the apparatus body of the image forming apparatus 100.

[0027] The front plate 100F and the rear plate 100B are positioned facing each other on one side and the other side in the axial direction of the photosensitive drum 2, with a sheet metal beam (not shown) bridging between them. The front plate 100F, the rear plate 100B, and the beam (not shown) each constitute part of the frame (housing) of the image forming apparatus 100. Here, with respect to the image forming apparatus 100 or its components in this embodiment, the front side or front edge 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.

[0028] The cartridge tray 30 is attached to the front plate 100F and the rear plate 100B at one end in the axial direction of the photosensitive drum 2. Details of the cartridge tray 30 will be described later.

[0029] The drum unit 23 and the developing unit 24 undergo changes over time due to repeated image formation processes, and are therefore designed as units (cartridges) that can be replaced or removed for maintenance. Figure 3 shows the arrangement of the drum unit 23, developing unit 24, and exposure head 4 when replacement or removal is performed. Unlike the image forming apparatus 100 shown in Figure 2, the image forming apparatus 100 shown in Figure 3 has the developing unit 24 and exposure head 4 retracted from and separated from the photosensitive drum 2.

[0030] This is because, as shown in Figure 2, if the developing unit 24 and exposure head 4 are kept in close proximity to the photosensitive drum 2, dynamic interference during unit attachment and detachment may cause damage to each unit, or even make it impossible to remove the unit. Therefore, when attaching or detaching the units, the developing unit 24 and exposure head 4 are moved away from the photosensitive drum 2 and separated from it by a retraction mechanism consisting of the developing stay 31, rotating arm 65, and lifting duct 69, as described later, as shown in Figure 3.

[0031] The drum unit 23 and the developing unit 24 are inserted and removed from the front side of the image forming apparatus 100 and mounted in predetermined positions (mounting positions) on the main body of the image forming apparatus 100. The image forming apparatus 100 is equipped with an inner door 102 that covers the front sides of both the drum unit 23 and the developing unit 24 mounted in the mounting positions. As shown in Figures 8 and 9, one end of the inner door 102 is fixed to the front side of the cartridge tray 30 by a hinge and is rotatable relative to the cartridge tray 30 by a hinge. The inner door 102 is a necessary component to protect each unit and make it difficult for the photosensitive drum 2 to be exposed to light outside of the image forming process, and is positioned opposite the front in the direction of insertion and removal of each color unit.

[0032] Furthermore, a front cover 101, which forms the exterior of the image forming apparatus 100, is provided on the front side of the apparatus. One end of the front cover 101 is fixed to the front side of the apparatus body of the image forming apparatus 100 by a hinge, and the hinge allows it to rotate relative to the apparatus body of the image forming apparatus 100. The front cover 101 is provided in front of (outside of) the inner door 102 in the axial direction of the photosensitive drum 2. In the closed state shown in Figure 1, the front cover 101 covers the entirety of the multiple inner doors 102 arranged in the left-right direction, forming the exterior of the front side of the apparatus.

[0033] Therefore, the replacement of the drum unit 23 and the developing unit 24 is performed by an operator using the following procedure. The operator opens the front cover 101 as shown in Figure 4, and then opens the inner doors 102 (102Y, 102M, 102C, 102K) as shown in Figure 5, to remove the drum unit 23 or developing unit 24 from inside the device. Figure 6 shows the drum unit 23 after it has been removed. Figure 7 shows the developing unit 24 after it has been removed. The replacement is then completed by inserting the new drum unit 23 or developing unit 24, closing the inner doors 102, and then closing the front cover 101.

[0034] Furthermore, the retraction mechanism for the developing unit 24 and exposure head 4 moves them away from the photosensitive drum 2 in conjunction with the opening of the inner door 102. Details of the retraction mechanism (developing stay 31, rotating arm 65, lifting duct 69) will be described later.

[0035] In the following explanation, the front side of the device is defined as the front (front or front) side, and the rear side is defined as the rear (back or rear) side. Furthermore, with respect to the photosensitive drum 2K on which the electrostatic latent image of the black toner is formed, the side on which the photosensitive drum 2Y on which the electrostatic latent image of the yellow toner is formed is defined as the left side. With respect to the photosensitive drum 2Y on which the electrostatic latent image of the yellow toner is formed, the side on which the photosensitive drum 2K on which the electrostatic latent image of the black toner is formed is defined as the right side. In addition, the direction perpendicular to the front-to-back and left-to-right directions defined here, and vertically upward, is defined as the upward direction, and the direction perpendicular to the front-to-back and left-to-right directions, and vertically downward, is defined as the downward direction. The defined front direction F, rear direction B, right direction R, left direction L, upward direction U, and downward direction D are shown in Figure 1.

[0036] In the following description, the axial direction of the photosensitive drum 2 corresponds to the front-to-back direction (front-to-back direction) shown in Figure 1. Similarly, the longitudinal direction of the exposure head 4 also corresponds to the front-to-back direction shown in Figure 1. In other words, the axial direction of the photosensitive drum 2 and the longitudinal direction of the exposure head 4 are the same direction. Furthermore, one end of the photosensitive drum 2 in the axial direction refers to the front side as defined here, and the other end refers to the rear side as defined here. The same applies to the front and rear ends in the front-to-back direction. In the left-to-right direction, one end refers to the left side as defined here, and the other end refers to the right side as defined here.

[0037] (Exposure head) Figures 10 to 18 are explanatory diagrams of the exposure head 4. Figure 10 is a schematic cross-sectional view of the exposure head 4. Figure 11 is a perspective view of the exposure head 4 from above. Figure 12 is a perspective view of the exposure head 4 from below.

[0038] The exposure head 4 is configured in an elongated shape (longitudinal shape) that extends in the axial direction of the photosensitive drum 2. The exposure head 4 comprises a substrate 50, a light-emitting element mounted on the substrate 50, a lens array 52, and a holding member that holds the substrate 50 and the lens array 52. ​​The holding member has a housing 54 and a housing support member 55 that supports the housing 54. Here, the exposure head 4 is equipped with an LED 51 as a light-emitting element that emits light.

[0039] Figures 13, 14, and 15 illustrate the substrate 50 and lens array 52 of the exposure head 4.

[0040] The substrate 50 will now be described. Figure 13(a) is a schematic perspective view of the substrate 50. Figure 13(b) shows the arrangement of LED chips 53 (53-1 to 53-29) including a plurality of LEDs 51 provided on the substrate 50. Figure 13(c) is an enlarged view of Figure 13(b). Figure 14 is a perspective view of the substrate 50 as seen from the side on which the LEDs 51 are mounted (the substrate surface). Figure 15 is a perspective view of the substrate 50 as seen from the side on which the FFC connector 57 is mounted (the substrate back surface). In the figures, one side of the arrow indicates the front side of the image forming apparatus 100, and the other side indicates the rear side of the image forming apparatus 100.

[0041] LED chips 53 (53-1 to 53-29) are mounted on the circuit board 50. As shown in Figures 13(a), 14, and 15, the LED chips 53 are provided on one side of the circuit board 50, and a long FFC connector 57 is provided on the other side. Here, one side of the circuit board 50 is the side on which the LED chips 53 are provided (top side, front side). The other side of the circuit board is the side opposite to the side on which the LED chips 53 are provided (bottom side, back side).

[0042] The FFC connector 57 is provided on the other side (bottom surface, back surface) of the substrate 50 such that its longitudinal direction aligns with the longitudinal direction of the substrate 50. The long FFC connector 57 is located on the front side of the image forming apparatus 100 (one side in the longitudinal direction of the substrate 50). Wiring for supplying signals to each LED chip 53 is provided on the substrate 50. One end of a flexible flat cable 58 (see Figure 25, hereinafter referred to as "FFC"), which is an example of a cable, is connected to the FFC connector 57.

[0043] The control circuit section of the image forming apparatus 100 is provided with a circuit board (not shown) that includes a control unit and a connector. The other end of the FFC 58 is connected to the connector of the control circuit section. In other words, the FFC 58 electrically connects the circuit board (control circuit section) of the apparatus body to the circuit board 50 of the exposure head 4.

[0044] Control signals (drive signals) are input to the substrate 50 of the exposure head 4 from the control circuit section of the main body of the image forming apparatus 100 via the FFC 58 and FFC connector 57. The control signals are transferred to each LED chip 53. The LED chips 53 are driven (light up, turn off) according to the control signals input to the substrate 50. The LED chips 53 mounted on the substrate 50 will be described in more detail below.

[0045] As shown in Figures 13(b) and 13(c), 29 LED chips 53-1 to 53-29, each containing multiple LEDs 51, are arranged on one side of the substrate 50. In this embodiment, each LED chip 53-1 to 53-29 has 516 LEDs 51 arranged in the longitudinal direction. In the longitudinal direction of the LED chip 53, the distance k2 between the centers of adjacent LEDs 51 corresponds to the recording resolution of the image forming apparatus 100. Since the recording resolution of the image forming apparatus 100 in this embodiment is 1200 [dpi], the distance k2 between the centers of the 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].

[0046] The photosensitive layer of the photosensitive drum 2 is formed with a length of 314 mm or more in the axial direction. Since the length of the long side of A4 size recording paper and the length of the short side of A3 size recording paper are 297 mm, the exposure head 4 of this embodiment has an exposure range capable of forming images on A4 size recording paper and A3 size recording paper P.

[0047] LED chips 53-1 to 53-29 are arranged in a staggered pattern along the axis of the photosensitive drum 2. Specifically, LED chips 53-1 to 53-29 are arranged alternately in two rows along the axis of the photosensitive drum 2. That is, as shown in Figure 13(b), the odd-numbered LED chips 53-1, 53-3, ... 53-29, counting from the left, are mounted in a single row along the longitudinal direction of the substrate 50 on one side in the axial direction. The even-numbered LED chips 53-2, 53-4, ... 53-28, counting from the left, are mounted in a single row along the longitudinal direction of the substrate 50 on the other side in the axial direction.

[0048] With this arrangement, as shown in Figure 13(c), the distance k1 between the centers of LED 51 at one end of LED chip 53-1 and LED 51 at the other end of LED chip 53-2 can be made equal to the distance k2 in the longitudinal direction of LED chip 53. The same applies to other LED chips 53. That is, the distance k1 between the centers of LED 51 located at one end of one LED chip 53 and the other end of the other LED chip 53 in different LED chips 53 adjacent to each other in the longitudinal direction becomes equal to the distance k2 between the centers of adjacent LED 51 on a single LED chip 53.

[0049] In this embodiment, an example using a semiconductor LED, which is a light-emitting diode, as the light-emitting element is described, but for example, an OLED (Organic Light Emitting Diode) can also be used as the light-emitting element. An OLED is also called an organic EL (Organic Electro-Luminescence) and is a current-driven light-emitting element. For example, the OLEDs are arranged in a line along the main scanning direction (the axial direction of the photosensitive drum 2) on a TFT (Thin Film Transistor) substrate and are electrically connected in parallel by power supply wiring also provided along the main scanning direction.

[0050] The lens array 52, which is a collection of lenses, will now be described. Figure 13(d) is a schematic diagram of the lens array 52 as seen from the photosensitive drum 2 side. Figure 13(e) is a schematic perspective view of the lens array 52.

[0051] The lens array 52 focuses the light emitted from the light-emitting element onto the photosensitive layer on the surface of the photosensitive drum 2. The lens array 52 is a lens assembly having multiple lenses. These multiple lenses are arranged in two rows along the arrangement direction of the multiple LEDs 51. Each lens is arranged alternately such that one lens from the other row is positioned so as to be in contact with both adjacent lenses in the arrangement direction of the lenses in one row. Each lens is a cylindrical glass rod lens, having a light incident surface 52b into which light emitted from the LED 51 enters, and a light exit surface 52a into which light that enters from the light incident surface exits (see Figure 10). Note that the material of the lens is not limited to glass, but may also be plastic. The shape of the lens is not limited to a cylinder, but may also be a polygonal prism such as a hexagonal prism.

[0052] The dotted line Z shown in Figure 13(e) indicates the optical axis of the lens. The exposure head 4 moves in a direction roughly aligned with the optical axis of the lens indicated by the dotted line Z (hereinafter also referred to as the "optical axis direction") by a retraction mechanism described later. Here, the optical axis of the lens refers to the line connecting the center of the light-emitting surface of the lens and the focal point of the lens. The lens array 52 is a lens assembly having multiple lenses, and the "optical axis" mentioned above is the optical axis of any of these multiple lenses.

[0053] Here, strictly speaking, the multiple lenses that make up the lens array 52 may be slightly tilted relative to each other. This is due to tolerances during assembly. However, deviations of this magnitude will not be considered when defining the direction of the optical axis. Therefore, we will assume that the optical axes of each of the multiple lenses are all in the same direction. The lens array 52 has the role of focusing the light emitted from the LED 51 onto the surface of the photosensitive drum 2.

[0054] The lens array 52 is mounted on the housing 54 during the assembly of the exposure head 4 such that the distance between the light-emitting surface of the LED 51 and the light-incident surface of the lens is approximately equal to the distance between the light-emitting surface of the lens and the surface of the photosensitive drum 2.

[0055] (Housing of exposure head 4) As shown in Figure 10, the housing 54 holds the lens array 52 and the substrate 50. In this embodiment, the housing 54 is a metal component formed by bending a plate material that has been plated, such as a galvanized steel sheet or a cold-rolled steel sheet. The housing 54 is formed into a U-shape by press working, for example, from a sheet metal such as a thin iron plate. The shape of the housing 54 will be described below.

[0056] The housing 54 has a flat portion (opposing surface) 54U into which a first opening 54a into which the lens array 52 is inserted is formed. The flat portion 54U faces the photosensitive drum 2 in the optical axis direction of the lenses of the lens array 52. ​​Note that the flat portion 54U is not limited to a flat surface, but may be a slightly curved surface. On one side of the flat portion 54U in the short direction, the housing 54 has an extension portion 54R that extends away from the photosensitive drum 2. On the other side of the flat portion 54U in the short direction, the housing 54 has an extension portion 54L that extends away from the photosensitive drum 2.

[0057] The extensions 54R and 54L serve as substrate support portions in the housing 54 for supporting the substrate 50 inserted through the second opening 54b. The flat portion 54U and the substrate support portions (extensions 54R, 54L) are integrated and constitute the housing 54 that holds the lens array 52 and the substrate 50, with a cross-section formed in a substantially U-shape. Because the housing 54 is formed in a substantially U-shape, the second opening 54b is formed on the opposite side of the flat portion 54U. The second opening 54b is formed between the substrate support portions (extensions 54L, 54R) that extend from the flat portion 54U toward the side away from the photosensitive drum.

[0058] The substrate 50 is inserted through the second opening 54b, that is, from the bottom of the U-shaped housing 54, and bonded to the inside of each substrate support portion (the inside of the extension portion 54L and the inside of the extension portion 54R) with adhesive. Since the position of the substrate 50 in the focal direction is determined by a jig (not shown), the exposure head 4 does not have a positioning mechanism for the substrate 50 in the focal direction.

[0059] Similarly, the lens array 52 is inserted into the first opening 54a formed in the flat portion 54U and then bonded to the flat portion 54U with adhesive. The lens array 52 is fixed to the flat portion 54U (housing 54) after its position and tilt in the focal direction have been adjusted using a jig so that the distance in the focal direction between the lens array 52 and all the LED chips 53 mounted on the substrate 50 is a predetermined value. The lens array 52 is fixed to the flat portion 54U with adhesive at multiple locations in the longitudinal direction. In other words, in this embodiment, the exposure head 4 has multiple bonding locations in the longitudinal direction of the flat portion 54U for bonding and fixing the lens array 52 inserted into the first opening 54a to the flat portion 54U.

[0060] After the substrate 50 and lens array 52 are positioned and fixed to the housing 54, the gap between the substrate 50 inserted into the second opening 54b and the housing 54 (extensions 54L, 54R) is sealed longitudinally by a sealant 59 (see Figures 16 and 17). Figure 16 is a perspective view from below of the exposure head 4 showing the substrate 50 with the LEDs 51 mounted on it assembled to the housing 54. Figure 17 is an enlarged view of the front of the exposure head 4 shown in Figure 16. This protects the LEDs 51 from contamination by toner and dust from the outside. Note that the sealant 59 only seals the gap (boundary) between the substrate 50 and the housing 54, and the FFC connector 57 and most of the substrate 50 are exposed.

[0061] Similarly, a sealant 59 is applied to the gap between the lens array 52 inserted into the first aperture 54a and the housing 54 (flat portion 54U). This gap is sealed longitudinally by the sealant 59, as shown in Figure 18. Figure 18 is a perspective view of the exposure head 4 with the lens array 52 assembled to the housing 54. More specifically, as shown in Figure 10, the sealant 59 seals the gap between the side wall of the lens array 52 along the longitudinal direction of the housing 54 and the edge of the first aperture 54a. This reduces the possibility that dust such as toner will flow in through the gap between the side wall of the lens array 52 and the first aperture 54a, and that the light emitted from the LED 51 will be blocked by the dust.

[0062] Naturally, the gaps sealed by the sealant 59 are 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 side wall of the lens array 52 refers to the side wall opposite to the side wall of the lens array 52. ​​Here too, the gap (boundary) between the housing 54 and the lens array 52 is sealed by the sealant 59. This prevents the LED 51 from being contaminated by toner or dust from the outside.

[0063] As described above, the substrate 50 and the lens array 52 are supported by the housing 54, so that the LED 51 and the incident surface 52b of the lens face each other. As a result, the light emitted from the LED 51 enters the incident surface 52b of the lens and is emitted from the exit surface 52a of the lens toward the photosensitive drum 2. In this embodiment, the light emitted from three LEDs 51 (multiple LEDs 51) can pass through the same single lens. Also, even the light emitted from a single LED 51 can pass through multiple lenses because it propagates radially. That is, the light emitted from multiple LEDs 51 passes through the lens array 52 (some of the multiple lenses in the lens array 52) to expose the photosensitive drum 2. Details about the adhesive and sealant 59 will be described later.

[0064] (Housing support member) As shown in Figures 11 and 12, the housing support member 55 supports the housing 54, which holds the substrate 50 and the lens array 52, along its longitudinal direction and is integrated with the housing 54. The housing support member 55 is a longitudinally shaped member that extends in the axial direction of the photosensitive drum 2.

[0065] As shown in Figure 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 opposite the left side wall 55L, and a bottom surface 55D which is between the left side wall 55L and the right side wall 55R and faces the flat surface 54U of the housing 54. Multiple openings 55a are provided in the bottom surface 55D of the housing support member 55 in the longitudinal direction which is the axial direction of the photosensitive drum 2.

[0066] The opening 55a of the housing support member 55 is located opposite the mounting surface (the front surface of the substrate 50) on which the LEDs 51 are mounted (the back surface of the substrate 50). The opening 55a is located between the left wall 55L and the right wall 55R in the short direction perpendicular to the longitudinal direction.

[0067] The first side wall, the left side wall 55L, is provided between the housing 54 that holds the substrate 50 and the developing unit 24 on one side in the short direction perpendicular to the axial direction of the photosensitive drum 2, as shown in Figure 21. The left side wall 55L is provided along the axial direction of the photosensitive drum 2 so as to separate the housing 54 and the developing unit 24. The second side wall, the right side wall 55R, is provided between the housing 54 and the adjacent drum unit 23, which is adjacent to the housing 54, on the other side in the short direction, as shown in Figure 21. The right side wall 55R, like the left side wall, is provided along the axial direction of the photosensitive drum 2 so as to separate the housing 54 and the drum unit 23.

[0068] By integrally providing the housing support member 55 with the housing 54, the airflow sent from the duct unit 60 (described later) is blown onto the back surface of the substrate 50 through the opening 55a between the left wall 55L and the right wall 55R of the housing support member 55. 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.

[0069] In this manner, the airflow blown from the opening 55a of the housing support member 55 onto the back surface of the substrate 50 is separated from the developing unit 24 adjacent to the exposure head 4 by the left wall 55L, and from the drum unit 23 by the right wall 55R. Therefore, the airflow that cools the exposure head 4 flowing into the back surface of the substrate 50 does not leak to the developing unit 24 adjacent to the exposure head 4, and the scattering of toner from the developing unit 24 inside the image forming apparatus 100 can be suppressed.

[0070] As shown in Figures 11 and 12, the exposure head 4 has first engaging parts, which are engaging claws 55b and 55c. The engaging claws 55b and 55c are provided on the housing support member 55 of the exposure head 4 and engage with the lifting duct 69, which will be described later, by snap-fit.

[0071] In the housing support member 55 of the exposure head 4, the bottom surface portion 55D between the opening 55a at one end (front side) in the longitudinal direction and the adjacent opening 55a is defined as the first bottom surface portion 55D1. Similarly, the bottom surface portion 55D between the opening 55a at the other end (rear side) in the longitudinal direction and the adjacent opening 55a is defined as the second bottom surface portion 55D2. The lower surface of the first bottom surface portion 55D1 is provided with an engaging claw 55b that engages with the lifting duct 69. The lower surface of the second bottom surface portion 55D2 is provided with an engaging claw 55c that engages with the lifting duct 69. The first bottom surface portion 55D1 and the second bottom surface portion 55D2, i.e., the bottom surface portions 55D, are opposing portions that face the upper surface portion 69U of the lifting duct 69.

[0072] The first engaging parts, the engaging claws 55b and 55c, are formed on the bottom surface 55D projecting toward the lifting duct 69 in the direction of movement of the lifting duct 69, and further extending in the axial direction of the photosensitive drum 2 perpendicular to the projection direction. Specifically, the engaging claws 55b and 55c of the exposure head 4 are formed projecting toward the lifting duct 69, and further extending in the axial direction of the photosensitive drum 2 perpendicular to the projection direction, forming a substantially L-shape. As will be described later, by sliding the exposure head 4, the substantially L-shaped tips of the engaging claws 55b and 55c engage with the edges of the engaging holes 69b and 69c by snap-fit, and become one with the lifting duct 69.

[0073] (Lifting duct) The image forming apparatus 100 is equipped with a lifting duct 69. The lifting duct 69 will be described with reference to Figures 21, 22, 26, and 27. Figures 21 and 22 are cross-sectional views of XX in Figure 19. Figures 26 and 27 are perspective views of the exposure head 4, the lifting duct 69, and the rotating arm 65.

[0074] The lifting duct 69 is an exposure support member that detachably supports the exposure head 4, and together with the cartridge tray 30 (described later), it is provided on the main body of the image forming apparatus 100. The lifting duct 69 is provided between the developing support member 301 that supports the developing unit 24 of the cartridge tray 30 and the drum support member 302 that supports the drum unit 23. The lifting duct 69 is movable between the developing support member 301 and the drum support member 302 of the cartridge tray 30, between an exposure position where the photosensitive drum 2 is exposed (see Figures 21 and 23) and a retracted position where it is moved away from the exposure position (see Figures 24 and 22).

[0075] The lifting duct 69 is supported from below at both ends in the longitudinal direction by a rotating arm 65, which will be described later. The lifting duct 69 is moved by the rotating arm 65 in a direction perpendicular to the axial direction of the photosensitive drum 2 (first direction, movement direction), together with the exposure head 4. The lifting duct 69 is moved to the exposure position or the retracted position by the rotation of the rotating arm 65.

[0076] The lifting duct 69 has a longitudinal shape that extends in the front-to-back direction (axis direction of the photosensitive drum 2), similar to the exposure head 4, so as to support the entire exposure head 4, and its central part has openings at the top and bottom. One opening 69a (see Figure 35) of the lifting duct 69 communicates with the opening 55a of the exposure head 4, and the other opening 64 communicates with the opening 61 of the duct unit 60, forming a duct. The lifting duct 69 supports the exposure head 4 and at the same time constitutes part of the duct that cools the exposure head 4.

[0077] The lifting duct 69 has an upper surface portion 69U (see Figure 25) that faces the bottom surface portion 55D of the housing support member 55. Multiple openings 69a are provided on the upper surface portion 69U of the lifting duct 69 in the longitudinal direction, which is the axial direction of the photosensitive drum 2. The lifting duct 69 has a left duct wall 69L (see Figure 21), a right duct wall 69R (see Figure 21) that faces the left duct wall 69L, a front duct wall 69F (see Figure 25), and a rear duct wall 69B (see Figure 25) that faces the front duct wall 69F. The left duct wall 69L, the right duct wall 69R, the front duct wall 69F, and the rear duct wall 69B are integrally provided on the upper surface portion 69U so as to surround the periphery of the upper surface portion 69U, that is, so as to surround the openings 69a provided on the upper surface portion 69U. As a result, the lifting duct 69 is formed with an integrated upper surface 69U, left duct wall 69L, right duct wall 69R, front duct wall 69F, and rear duct wall 69B, and has openings at the top and bottom. The lifting duct 69 forms a duct (closed space) that allows airflow from the duct unit 60 (described later) to flow to the exposure head 4 through the gaps between the duct walls and the opening 69a in the upper surface 69U.

[0078] The multiple openings 69a are each provided in positions opposite to the multiple openings 55a provided in the bottom surface portion 55D of the housing support member 55. In other words, the openings 69a of the lifting duct 69 are provided in positions opposite to the back surface of the substrate 50, similar to the openings 55a of the housing support member 55. In other words, the lifting duct 69 has an opening 69a that communicates with the opening 55a of the exposure head 4.

[0079] The first duct wall, the left duct wall 69L, is located on the left side, which is one side in the shorter direction perpendicular to the axial direction of the photosensitive drum 2, via an opening 69a. That is, the left duct wall 69L is located opposite the developing unit 24 and extends from the front duct wall 69F to the rear duct wall 69B along the axial direction of the photosensitive drum 2.

[0080] The left wall 69L of the duct has a first inclined surface 69L1 that, in the direction of movement from the exposure position to the retraction position, is inclined away from the right wall 69R of the duct from the upstream side to the downstream side. The first inclined surface 69L1 is similarly inclined from the front wall 69F of the duct to the rear wall 69B of the duct. The first inclined surface 69L1 is provided at a position opposite the developing support member 301 of the left wall 69L of the duct and forms a predetermined angle θ2 with respect to the direction of movement (direction of arrow G shown in Figure 21).

[0081] The second duct wall, the right duct wall 69R, is located on the right side, which is the other side in the shorter direction, through an opening 69a. That is, the right duct wall 69R is located opposite the drum unit 23, which is adjacent to the lifting duct 69, and is provided along the axial direction of the photosensitive drum 2, extending from the front duct wall 69F to the rear duct wall 69B.

[0082] The right wall 69R of the duct has a second inclined surface 69R1 that, in the direction of movement from the exposure position to the retraction position, is inclined away from the left wall 69L of the duct from the upstream side to the downstream side. The second inclined surface 69R1 is similarly inclined from the front wall 69F of the duct to the rear wall 69B of the duct. The second inclined surface 69R1 is provided at a position opposite the drum support member 302 of the right wall 69R of the duct and forms a predetermined angle θ1 with respect to the direction of movement (direction of arrow G shown in Figure 21).

[0083] The third duct wall, the front duct wall 69F, is located outside the multiple openings 69a provided on the upper surface 69U in the axial direction of the photosensitive drum 2. The fourth duct wall, the rear duct wall 69B, is located outside the multiple openings 69a provided on the upper surface 69U in the axial direction of the photosensitive drum 2. The multiple openings 69a provided on the upper surface 69U of the lifting duct 69 are located between the left duct wall 69L and the right duct wall 69R, and between the front duct wall 69F and the rear duct wall 69B.

[0084] In other words, the lifting duct 69 is formed in a hollow shape with openings at the top and bottom, but without openings at the positions facing the developing unit 24 and drum unit 23 due to these duct walls. Therefore, the lifting duct 69 allows the airflow from the duct unit 60, described later, to flow to the back surface of the substrate 50 of the exposure head 4 through the opening 64, described later, and the opening 69a between the left wall 69L and the right wall 69R of the duct. As a result, the lifting duct 69 can allow the airflow from the duct unit 60 to flow to 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.

[0085] Furthermore, the front wall 69F and rear wall 69B of the duct extend downward in the direction of movement compared to the left wall 69L and right wall 69R of the duct. In other words, the front wall 69F and rear wall 69B of the duct are ribs that protrude toward the duct unit 60, which will be described later, on both longitudinal sides of the opening 69a that communicates with the exposure head 4.

[0086] The lifting duct 69 integrally supports the exposure head 4 and, by communicating with the duct unit 60 described later, forms a duct (part of the second cooling duct) that allows the airflow from the duct unit 60 to flow to the exposure head 4 through the opening 69a. The duct walls 69F and 69B, acting as ribs, form part of the duct at the exposure position. The front duct wall 69F and the rear duct wall 69B, together with the cartridge tray 30 described later, form an opening 64 (see Figure 20) that communicates with the opening 61 of the duct unit 60 described later.

[0087] Furthermore, the lifting duct 69 has a first engaging portion 69d and a second engaging portion 69e at both ends in the longitudinal direction, which engage with the rotating arm 65 (see Figures 23 and 24). The first engaging portion 69d is located on the outside of the duct front wall 69F at one end in the longitudinal direction. The first engaging portion 69d is also located on the outside of the area where the FFC connector 57 is provided, which is located on the outside of the duct front wall 69F at one end in the longitudinal direction. The second engaging portion 69e is located on the outside of the duct rear wall 69B at the other end in the longitudinal direction.

[0088] Therefore, the region where the first engaging portion 69d is provided (range Lm in Figure 19) and the region where the second engaging portion 69e is provided (range Lm in Figure 19) are located outside the duct region (range La in Figure 19) where the opening 69a is surrounded by the duct wall. In other words, the duct region (range La in Figure 19) where the opening 69a is surrounded by the duct wall is located between the region where the first engaging portion 69d is provided (range Lm in Figure 19) and the region where the second engaging portion 69e is provided (range Lm in Figure 19).

[0089] The area where the FFC connector 57 is provided (area Lc in Figure 19) is located outside the duct area (area La in Figure 19) which forms a duct with the opening 69a surrounded by the duct wall, and is located between the duct area and the area where the first engaging portion 69d is provided (area Lm in Figure 19). Furthermore, the duct-forming area La includes most of the substrate 50 on which the LED 51 is mounted. By blowing airflow into area La, sufficient cooling of the exposure head 4 is possible. Area Lc is the mounting area for the FFC connector 57 of the signal line that transmits the drive signal to the substrate 50 on which the LED 51 is mounted. Although there is no opening to form a duct in area Lc, as described above, it is configured so that sufficient cooling can be achieved in area La.

[0090] As a result, air taken in from outside the device by the duct unit 60 (described later) is blown onto the back surface of the substrate 50 through the opening 55a of the exposure head 4 via the lifting duct 69. The airflow blown onto the back surface of the substrate 50 through the opening 55a of the exposure head 4 is then exhausted to the outside of the device by the duct unit 60 via the lifting duct 69.

[0091] (connecting hole) As shown in Figure 25, the lifting duct 69 has engagement holes 69b and 69c, which are second engagement parts. The engagement holes 69b and 69c, which are the second engagement parts, engage with the engagement claws 55b and 55c, which are the first engagement parts of the exposure head 4, by snap-fit.

[0092] In the lifting duct 69, the upper surface portion 69U between the opening 69a at one end in the longitudinal direction (front side) and the adjacent opening 69a is defined as the first upper surface portion 69U1. Similarly, the upper surface portion 69U between the opening 69a at the other end in the longitudinal direction (rear side) and the adjacent opening 69a is defined as the second upper surface portion 69U2. The first upper surface portion 69U1 is provided with an engagement hole 69c that engages with the engagement claw 55c of the exposure head 4. The second upper surface portion 69U2 is provided with an engagement hole 69b that engages with the engagement claw 55b of the exposure head 4. The first upper surface portion 69U1 and the second upper surface portion 69U2, i.e., the upper surface portions 69U, face the bottom surface portion 55D of the exposure head 4 (housing support member 55) and are support portions that detachably support the exposure head 4.

[0093] The second engaging portion, the engaging holes 69b and 69c, are formed on the upper surface portion 69U facing the exposure head 4, at positions corresponding to the engaging claws 55b and 55c. This allows the exposure head 4 to be detachably attached to the image forming apparatus 100. The exposure head 4 is moved (downward D as shown in Figure 35) so that the engaging claws 55b and 55c of the exposure head 4 are dropped into the engaging holes 69b and 69c of the lifting duct 69, respectively, and the bottom surface portion 55D of the exposure head 4 comes into contact with the upper surface portion 69U of the lifting duct 69. In other words, by moving the exposure head 4 in a direction perpendicular to the axial direction of the lifting duct 69, the engaging claws 55b and 55c are engaged with the engaging holes 69b and 69c in a protruding direction.

[0094] Subsequently, by moving the exposure head 4 along the upper surface 69U of the lifting duct 69 (rearward direction B as shown in Figure 38), the engaging claws 55b and 55c of the exposure head 4 are snap-fitted into the engaging holes 69b and 69c of the lifting duct 69, respectively. That is, by moving the exposure head 4 axially relative to the lifting duct 69, the engaging claws 55b and 55c are engaged with the engaging holes 69b and 69c in an extending direction perpendicular to the protruding direction. In this way, the exposure head 4 is connected to the lifting duct 69 in the image forming apparatus 100, and the exposure head 4 becomes an integral part of the lifting duct 69. The procedure for removing the exposure head 4 from the lifting duct 69 is the reverse of the procedure described above. The replacement and attachment / detachment configuration of the exposure head 4 will be explained in detail later.

[0095] (Cartridge tray) The cartridge tray 30 will be described using Figures 8, 9, 19, 20, and 21. Figures 8, 9, and 19 are perspective views of the cartridge tray 30. Figure 20 is a view of the cartridge tray 30 from below.

[0096] The cartridge tray 30 is a support member that supports the drum unit 23 and the developing unit 24 described above, and guides and supports the attachment and detachment operation along the axial direction of the photosensitive drum 2. The cartridge tray 30 pivots the pivot shaft 102a of the inner door 102 so that the inner door 102 can rotate freely within a predetermined range.

[0097] A cartridge tray 30 is provided for each image forming unit 1. Each cartridge tray 30 includes a developing support member 301 that guides and supports the attachment and detachment of the developing unit 24 along the axial direction of the photosensitive drum 2, and a drum support member 302 that guides and supports the attachment and detachment of the drum unit 23 along the axial direction of the photosensitive drum 2. The cartridge tray 30 is formed integrally with the developing support member 301 and the drum support member 302. Note that the configuration of providing a cartridge tray 30 for each image forming unit 1 is not limited to this.

[0098] The lifting duct 69 is movably positioned between the developing support member 301 and the drum support member 302 of the cartridge tray 30. Between the developing support member 301 and the drum support member 302, the first engaging portion 69d and the second engaging portion 69e at both ends in the longitudinal direction of the lifting duct 69 are supported from below by a rotating arm 65. The rotating arm 65 is rotatably mounted on the developing support member 301 of the cartridge tray 30, as will be described later. The exposure head 4 is detachably mounted on the lifting duct 69, which is movably positioned on the cartridge tray 30. In other words, the cartridge tray 30 is a support member that supports the exposure head 4 and guides and supports the attachment and detachment operation along the axial direction of the photosensitive drum 2.

[0099] The developing support member 301 is a developing support member that guides and supports the attachment and detachment operation of the developing unit 24 along the axial direction of the photosensitive drum 2, and is a longitudinally shaped member that extends in the axial direction of the photosensitive drum 2. The developing support member 301 has a first developing guide portion 301a, a second developing guide portion 301b facing the first developing guide portion 301a, and a developing bottom portion 301c provided between the first developing guide portion 301a and the second developing guide portion 301b. The developing support member 301 is integrally formed with the first developing guide portion 301a, the second developing guide portion 301b, and the developing bottom portion 301c.

[0100] The developing bottom portion 301c faces the bottom portion 24D of the frame of the developing unit 24 with a space between them, and is provided along the longitudinal direction, which is the axial direction of the photosensitive drum 2. The first developing guide portion 301a is provided on one end of the developing bottom portion 301c in the short direction perpendicular to the longitudinal direction, and is provided between the lifting duct 69 and the developing unit 24 so as to separate the lifting duct 69 from the developing unit 24. The second developing guide portion 301b is provided on the other end of the developing bottom portion 301c in the short direction, and is provided so as to face the first developing guide portion 301a. The first developing guide portion 301a and the second developing guide portion 301b each abut the frame of the developing unit 24 and guide the developing unit 24, which is inserted and removed in the longitudinal direction, along the longitudinal direction.

[0101] The first developing guide section 301a has a facing section 301d that faces the first inclined surface 69L1 of the lifting duct 69. The facing section 301d has a first tray inclined surface that is inclined in the same way as the first inclined surface 69L1 of the lifting duct 69.

[0102] The first development guide section 301a has a partition wall section 301e downstream of the opposing section 301d in the direction of movement from the retracted position of the lifting duct 69 toward the exposure position. The partition wall section 301e is provided between the exposure head 4 and the development unit 24 so as to separate the exposure head 4, which is located at the exposure position shown in Figure 21, from the development unit 24. The partition wall section 301e is the end (upper end) on the development sleeve 5 side of the first development guide section 301a.

[0103] As shown in Figures 2, 8, and 21, the developing support member 301 (cartridge tray 30) is positioned directly below the developing unit 24. The developing support member 301 (cartridge tray 30) forms a closed duct space between its upper surface and the bottom surface of the developing unit 24. In addition to guiding the attachment and detachment of the developing unit 24, it also functions as an intermediate path for the developing cooling airflow, which will be described later.

[0104] The flat space formed between the upper surface of the cartridge tray 30 (developing support member 301) and the upper surface of the developing unit 24 becomes a duct. The opening at one end of this duct in the longitudinal direction (front side) communicates with the opening 41a of the front duct 41, which takes in air from outside the device, via the opening 102c of the inner door 102 (see Figure 31). The duct between the developing unit 24 and the developing support member 301 forms a single closed space that communicates with the front duct 41 and the rear duct 42.

[0105] The drum support member 302 is a photoreceptor support member that guides and supports the attachment and detachment operation of the drum unit 23 along the axial direction of the photoreceptor drum 2, and is a longitudinally shaped member that extends in the axial direction of the photoreceptor drum 2. The drum support member 302 has a first drum guide portion 302a, a second drum guide portion 302b facing the first drum guide portion 302a, and a drum bottom portion 302c provided between the first drum guide portion 302a and the second drum guide portion 302b. The drum support member 302 is integrally formed with the first drum guide portion 302a, the second drum guide portion 302b, and the drum bottom portion 302c.

[0106] The drum bottom portion 302c faces the bottom 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 on one end of the drum bottom portion 302c in the short direction perpendicular to the longitudinal direction and is provided between the lifting duct 69 and the drum unit 23 so as to separate the lifting duct 69 from the drum unit 23. The second drum guide portion 302b is provided on the other end of the drum bottom portion 302c in the short 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 the frame of the drum unit 23 and guide the drum unit 23, which is inserted and removed in the longitudinal direction, along the longitudinal direction.

[0107] The first drum guide portion 302a has a facing portion 302d that faces the second inclined surface 69R1 of the lifting duct 69. The facing portion 302d has a second tray inclined surface that is inclined in the same way as the second inclined surface 69R1 of the lifting duct 69.

[0108] (Cartridge tray and lifting duct) The relationship between the cartridge tray 30 and the lifting duct 69 will now be explained. The lifting duct 69 is movably positioned between the first development guide section 301a and the first drum guide section 302a in the cartridge tray 30, and moves between the exposure position shown in Figure 23 and the retracted position shown in Figure 24 by the rotation of the rotating arm 65, which will be described later. In other words, the first development guide section 301a and the first drum guide section 302a of the cartridge tray 30 function as guide members that guide the lifting duct 69 in its direction of movement.

[0109] Furthermore, the lifting duct 69 becomes integrated with the exposure head 4 when the exposure head 4 is detachably attached to it, as the opening 55a of the exposure head 4 and the opening 69a of the lifting duct 69 communicate with each other. The lifting duct 69 is separated from the development unit 24 by the first development guide portion 301a of the cartridge tray 30, and separated from the drum unit 23 by the first drum guide portion 302a of the cartridge tray 30. In addition, at the exposure position shown in Figure 21, the gap between the lifting duct 69 and the first development guide portion 301a is sealed by a seal 72, which is a sealing member described later. Similarly, at the exposure position shown in Figure 21, the gap between the lifting duct 69 and the first drum guide portion 302a is sealed by a seal 71, which is a sealing member described later.

[0110] In this way, the cartridge tray 30 and the lifting duct 69, which is positioned between the first development guide section 301a and the first drum guide section 302a of the cartridge tray 30, form a duct that is a closed space communicating with the opening 55a of the exposure head 4.

[0111] (Relationship between cartridge tray, lifting duct and duct unit) The cartridge tray 30 and the lifting duct 69 have an opening 64 on the side facing the duct unit 60, which will be described later, that communicates with the opening 61 of the duct unit 60. The opening 64 formed by the cartridge tray 30 and the lifting duct 69 will be explained using Figures 20 and 21.

[0112] The opening 64 formed by the cartridge tray 30 and the lifting duct 69 is formed by the developing support member 301, the drum support member 302, and the lifting duct 69 between the developing support member 301 and the drum support member 302, as shown in Figure 20. More specifically, the opening 64 is formed by the developing guide section 301a, the drum guide section 302a, and the front wall 69F and rear wall 69B of the lifting duct 69 between the developing guide section 301a and the drum guide section 302a.

[0113] In this way, the cartridge tray 30 and the lifting duct 69 have openings 64 on the side facing the duct unit 60 (described later) that communicate with the opening 61 of the duct unit 60. When the duct unit 60 (described later) is mounted on the image forming apparatus 100, the opening 61 of the duct unit 60 is pressed from below against the opening 64 formed by the cartridge tray 30 and the lifting duct 69. As a result, the opening 64 formed by the cartridge tray 30 and the lifting duct 69 communicates with the opening 61 of the duct unit. The space 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. The sealing member 207 is an elastic material such as sponge or rubber made of urethane or silicone.

[0114] (Development Stay) The cartridge tray 30 includes a developing stay 31 that can slide along the axial direction of the photosensitive drum 2. The developing stay 31 will be described with reference to Figures 28 and 29. Figures 28 and 29 are side views of the developing stay 31 as seen from the right.

[0115] The developing stay 31, which is a sliding member, is movably mounted relative to the developing support member 301 of the cartridge tray 30. The developing stay 31 is movably mounted on the developing bottom surface portion 301c of the developing support member 301 in the axial direction of the photosensitive drum 2. The developing stay 31 has an elongated shape (longitudinal shape) extending in the axial direction of the photosensitive drum 2 and includes a developing pressure block 32, a developing pressure block 33, a developing stay link 34, an arm retraction member 68F, and an arm retraction member 68B.

[0116] The developing stay link 34 is fixed to the front end of the developing stay 31 and engages with the inner door 102 which is pivotally supported by the cartridge tray 30. The developing pressure block 32 is fixed to one longitudinal side (front side) of the developing stay 31, and the developing pressure block 33 is fixed to the other longitudinal side (rear side) of the developing stay 31. The developing pressure blocks 32 and 33 are positioned opposite the developing unit 24.

[0117] The inner door 102 has a link engagement portion 102b that engages with the developing stay link 34, positioned even closer to the end than the pivot axis 102a. Therefore, as the inner door 102 rotates, the link engagement portion 102b of the inner door 102 moves in the rotational direction along the trajectory of a circle with a radius equal to the distance between the pivot axis 102a and the link engagement portion 102b. In other words, as shown in Figure 29, opening the inner door 102 causes the link engagement portion 102b to also rotate and move towards the rear of the device.

[0118] This causes the developing stay link 34, which engages with the link engagement portion 102b of the inner door 102, to slide in the direction of arrow B, which is towards the rear of the device, and the two developing pressure blocks 32 and 33, which are integrally formed through the developing stay 31, also slide in the direction of arrow B. As shown in Figure 29, this means that the two developing pressure blocks 32 and 33 are released from the position that holds the developing unit 24. When the developing pressure blocks 32 and 33 are released from their holding position, the developing unit 24 moves in the direction of arrow D, which is the direction that moves it away from the photosensitive drum 2 due to its own weight.

[0119] From the above explanation, it can be seen that the developing unit 24 retracts from the photosensitive drum 2 in conjunction with the opening of the inner door 102. When closing the inner door 102, the developing unit 24 is moved toward the photosensitive drum 2 and pressed down by following the reverse procedure of the opening operation.

[0120] In this manner, the developing stay 31 slides in the front-rear direction by a developing stay link 34 that engages with a link engagement portion 102b, in conjunction with the opening and closing operation of the inner door 102. The sliding movement of the developing stay 31 in the front-rear direction moves the developing unit 24 between a developing position (see Figure 21) where the developing sleeve 5 is close to the photosensitive drum 2 during development, and a separated position (see Figure 22) where the developing sleeve 5 is separated from the photosensitive drum 2 when not developing.

[0121] As shown in Figure 28, the developing stay 31 slides forward F in conjunction with the closing of the inner door 102. At this time, the developing unit 24 moves upward (arrow U) along the slopes of the developing pressure blocks 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves closer to the photosensitive drum 2 of the drum unit 23.

[0122] Furthermore, as shown in Figure 29, the developing stay 31 slides backward B in conjunction with the opening of the inner door 102. At this time, the developing unit 24 moves downward (arrow D) along the slope of the developing pressure slabs 32 and 33 of the developing stay 31. As a result, the developing sleeve 5 of the developing unit 24 moves away from the photosensitive drum 2 of the drum unit 23, and the developing sleeve 5 is separated from the photosensitive drum 2 compared to during development.

[0123] Furthermore, the developing stay 31 includes an arm retraction member 68F and an arm retraction member 68B for rotating the rotating arm 65, which will be described later. The arm retraction members 68F and 68B are integrally formed with the developing stay 31. The arm retraction member 68F is fixed to one side of the developing stay 31 in the longitudinal direction (front side of the device) and is provided on the side opposite to the developing pressure chamber 32. The arm retraction member 68B is fixed to the other side of the developing stay 31 in the longitudinal direction (rear side of the device) and is provided on the side opposite to the developing pressure chamber 33. The arm retraction members 68F and 68B move in the same direction as the developing stay 31 slides in the front-rear direction in conjunction with the opening and closing operation of the inner door 102, thereby rotating the rotating arm 65.

[0124] The developing stay 31 disengages from the rotating arm 65 by moving in one direction along the axis. This causes the rotating arm 65 to rotate in one direction, moving the exposure head 4 to the exposure position together with the lifting duct 69. The developing stay 31 engages with the rotating arm 65 by moving in the other direction along the axis. This causes the developing stay 31 to rotate the rotating arm 65 in the other direction, moving the exposure head 4 to the retracted position together with the lifting duct 69.

[0125] (Positioning of the exposure head) The positioning of the exposure head 4 will be explained with reference to Figures 25 and 32-35.

[0126] First, the positioning pins 45F and 45B of the exposure head 4 (see Figures 11, 12, and 35) will be described. The housing 54 of the exposure head 4 is provided with positioning pins 45F and 45B, which are positioning axes. Both positioning pins 45F and 45B are examples of metal pins. The housing 54 is made of a conductive material, and the positioning pins are also made of a conductive material.

[0127] Positioning pins 45F and 45B are fixed to both ends of the housing 54 in the longitudinal direction, respectively. Positioning pin 45F is fixed to the housing 54 on one side (front side) of the lens array 52 in the axial direction of the photosensitive drum 2, and protrudes from both sides of the housing 54 in the optical axis direction of the lens array 52. ​​Positioning pin 45B is fixed to the housing 54 on the other side (rear side) of the lens array 52 in the axial direction of the photosensitive drum 2, and protrudes from both sides of the housing 54 in the optical axis direction of the lens array 52.

[0128] The positioning pins 45F and 45B are crimped to the housing 54 after adjusting the position of the positioning surface at the tip of the shaft relative to the housing 54, in order to ensure high precision in the distance between the surface of the photosensitive drum 2 and the light-emitting surface of the lens array 52 of the exposure head 4. However, the fixing of the positioning pins 45F and 45B to the housing 54 is not limited to this; for example, metal positioning pins 45F and 45B may be fixed to the metal housing 54 by welding. Thus, in this embodiment, the positioning pins 45F and 45B are integrated with the housing 54.

[0129] The positioning pins 45F and 45B of the exposure head 4 abut against the drum bearing 26 of the drum unit 23 in the direction of movement of the lifting duct 69, thereby creating a gap between the lens array 52 and the photosensitive drum 2. In this way, the distance (gap) between the exposure head 4 and the photosensitive drum 2 is determined in a direction perpendicular to the axial direction of the photosensitive drum 2, and the position of the exposure head 4 relative to the photosensitive drum 2 is determined.

[0130] The exposure head 4 is fixed not only in distance from the photosensitive drum 2 but also in angle by positioning pins 45F and 45B. In the image forming apparatus 100 shown in Figure 2, the exposure head 4 is positioned to face the center of the photosensitive drum 2. This arrangement is possible because, due to the mechanism of the LED (light-emitting element) 51 in the exposure head 4, it is not necessary to consider the effect of specular reflection on the surface of the photosensitive drum 2.

[0131] Figure 32 is a cross-sectional view showing the relationship between three components: the photosensitive drum 2, a portion of the positioning pins 45F and 45B (the tip on the positioning side), and the rotating arm 65. Figure 32 is a YY cross-sectional view of Figure 23, but with only the surrounding components of these three components visualized. The cross-sectional position has been moved to the center of the positioning pins 45F and 45B. Figure 33 is a perspective view taken from the front, cut in a direction perpendicular to the axial direction of the photosensitive drum 2 at the center position of the positioning pins 45F and 45B. Figure 34 is a perspective view taken from the rear, cut in a direction perpendicular to the axial direction of the photosensitive drum 2 at the center position of the positioning pins 45F and 45B.

[0132] In Figures 32 and 33, the optical axis direction of the exposure head 4 is positioned by the positioning pin 45F (45B) on the front side of the exposure head 4 and the drum bearing 26 on the front side of the photosensitive drum 2 abutting against the end face of the positioning pin 45F (45B).

[0133] Each drum bearing 26 has a recessed engaging portion 26F, 26B integrally formed at a position opposite to each positioning pin 45F, 45B, so that it can engage with the tip of each positioning pin 45F, 45B. By precisely machining the diameter of the tip of the positioning pin 45 and the width of the recessed portion of the drum bearing 26, precise positioning is achieved in a direction perpendicular to the optical axis direction of the exposure head 4 and perpendicular to the axial direction of the photosensitive drum 2. In addition, a slope is formed at the entrance to the engaging portion 26F, 26B of the drum bearing 26 to prevent the positioning pins 45F, 45B from riding up onto the edge of the recessed portion when engaging with it.

[0134] As shown in Figure 25, the positioning pins 45F and 45B and the drum bearing 26 are not in contact in the axial direction of the photosensitive drum 2, and are positioned by the positioning member 250, which will be described later.

[0135] The drum bearing 26 is a bearing member in the drum unit 23 that pivotally supports the front and rear ends (both ends) of the photosensitive drum 2. By increasing the dimensional accuracy at the engagement points of the drum bearing 26, the photosensitive drum 2 is pivotally supported by the drum bearing 26 without any gaps. In other words, high-precision positioning on the drum bearing 26 can be considered as high-precision positioning of the photosensitive drum 2. The photosensitive drum 2 is rotationally driven in accordance with the image forming process. Therefore, the positioning pin 45 of the exposure head 4 is positioned relative to the drum bearing 26.

[0136] Figures 32 and 33 show cross-sections of the front drum bearing 26 of the image forming apparatus 100, but the rear drum bearing 26 has a similar shape. As shown in Figure 34, the positioning pins 45B of the exposure head 4 are also positioned with high precision relative to the rear drum bearing 26 of the image forming apparatus 100. Therefore, the exposure head 4 is positioned with high precision at both ends in the axial direction of the photosensitive drum 2.

[0137] As shown in Figure 32, the pressing position where the engaging boss 66 of the rotating arm 65 presses against the lifting duct 69, the contact positions between the positioning pins 45F and 45B and the engaging portions 26F and 26B of the drum bearing 26, and the center position of the photosensitive drum 2 are arranged in approximately a straight line (dotted line). 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 the tilt of the exposure head 4 relative to the photosensitive drum 2, which leads to positioning accuracy in distance and angle, and stability in repeated attachment and detachment operations.

[0138] As shown in Figures 33 and 34, the positioning pins 45F and 45B are fitted to the auxiliary fitting portions 30h and 30i of the cartridge tray 30 at their lower end circumferential surfaces. The positioning pins 45F and 45B are auxiliaryly fitted to the auxiliary fitting portions 30h and 30i of the cartridge tray 30 in directions perpendicular to the optical axis direction of the exposure head 4 and perpendicular to the axial direction of the photosensitive drum 2. As a result, even if a slight rotational moment is generated due to the weight of the parts, surface properties, dimensional errors, etc., stable positioning accuracy in terms of distance and angle, as well as the ability to repeatedly attach and detach the parts, can be achieved.

[0139] (Replacing / attaching the exposure head) The replacement and attachment / detachment configuration of the exposure head 4 will be explained in detail using Figures 30 and 35 to 49. Figure 30 is a cross-sectional view of XX in Figure 19, similar to Figure 21. Figure 30 is a front cross-sectional view of the exposure head 4, lifting duct 69, and cartridge tray 30, without showing the drum unit 23 or developing unit 24. 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 35 to 49.

[0140] Figure 35 is a right-side perspective view showing the state immediately before the exposure head 4 is attached to the lifting duct 69, Figure 36 is a front cross-sectional view, and Figure 37 is a left-side perspective view. In the state shown in Figures 35 and 37, the drum unit 23, the developing unit 24, and the positioning member 250 have been removed from the image forming apparatus 100. The replacement and attachment / detachment of the exposure head 4 is performed 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 is configured to be manually moved from the retracted position to the exposure position. Therefore, when replacing or attaching / detaching the exposure head 4, the procedure is performed with the exposure head 4 manually moved to the exposure position. At this time, as shown in Figure 36, the FFC 58 connected to the main body of the apparatus is pre-connected to the FFC connector 57 of the exposure head 4.

[0141] As described above, the housing support member 55 of the exposure head 4 is provided with engaging claws 55b and 55c for engaging with the lifting duct 69. On the other hand, the lifting duct 69 is provided with engaging holes 69b and 69c on the upper surface portion 69U facing the exposure head 4 for engaging with the engaging claws 55b and 55c. The procedure for engaging the engaging claws 55b and 55c of the exposure head with the engaging holes 69b and 69c of the lifting duct and integrating them is as follows.

[0142] First, as shown in Figures 35 and 37, by moving the exposure head 4 in the direction of arrow D relative to the lifting duct 69, the engaging claws 55b and 55c of the exposure head 4 are dropped into the engaging holes 69b and 69c of the lifting duct 69, respectively. That is, the engaging claws 55b and 55c of the exposure head are engaged with the engaging holes 69b and 69c in a protruding direction. At the same time, the lower end of the positioning pin 45F of the exposure head 4 is dropped into the auxiliary fitting portion 30h of the cartridge tray 30 with a gap. At this time, the excess length of the FFC 58 connected to the substrate of the main body of the device and the substrate of the exposure head 4 protrudes from the harness opening 252. This state is shown in Figures 38 to 42.

[0143] Figure 38 is a right-side perspective view with the exposure head 4 placed in the lifting duct 69, Figure 39 is a front cross-sectional view, and Figure 40 is a left-side perspective view. Figure 41 is a cross-sectional view with the exposure head 4 placed in the lifting duct 69. Figure 42 is a perspective view of the vicinity of the conductive member with the exposure head 4 placed in the lifting duct 69.

[0144] As shown in Figure 38, the exposure head 4 is slid in the direction of arrow B relative to the lifting duct 69, and the engaging claws 55b and 55c are engaged with the engaging holes 69b and 69c in an extending direction perpendicular to the protruding direction. The state at this time is shown in Figures 43 to 46.

[0145] Figure 43 is a right-side perspective view of the exposure head 4 mounted on the lifting duct 69, and Figure 44 is a left-side perspective view. Figure 45 is a cross-sectional view of the WW section in Figure 30, showing the exposure head 4 mounted on the lifting duct 69. Figure 46 is an enlarged cross-sectional view of the engagement portion shown in Figure 45. Figure 48 is a front cross-sectional view of the FFC 58 after excess length processing. Figure 49 is a front cross-sectional view showing the state of the FFC 58 in the retracted position.

[0146] The engaging claws 55b and 55c of the exposure head 4 are formed to protrude toward the lifting duct 69 and have a roughly L-shape that extends in the direction of arrow B, which is the sliding direction of the exposure head 4. Therefore, when the exposure head 4 slides in the direction of arrow B, the tips of the roughly L-shaped claws 55b and 55c engage with the edges of the engaging holes 69b and 69c. Through this engagement, the exposure head 4 is mounted on the lifting duct 69 and becomes integrated with the lifting duct 69 at the positions shown in Figures 43 to 45.

[0147] In this manner, after stabilizing the position of the exposure head 4 with its engaging claws 55b and 55c passing through the engaging holes 69b and 69c of the lifting duct 69, the exposure head 4 is slid to complete the mounting. This makes it possible to achieve easy mounting of the exposure head 4 with an inexpensive configuration.

[0148] Referring to Figure 46, the relationship between the engagement claws of the exposure head 4 and the engagement holes of the lifting duct 69 will be explained in more detail. Here, the relationship between the engagement claws 55b of the exposure head 4 and the engagement holes 69b of the lifting duct 69 is explained, but the relationship between the engagement claws 55c of the exposure head 4 and the engagement holes 69c of the lifting duct 69 is similar.

[0149] The engaging claw 55b is elastic, and a recess 55f is provided at the extended tip of the engaging claw 55b. A protrusion 69f that engages with the recess 55f is provided on the edge of the engaging hole 69b corresponding to the recess 55f. The protrusion 69f provided on the edge of the engaging hole 69b is positioned at the location where the sliding movement of the exposure head 4 relative to the lifting duct 69 is completed, i.e., the mounting completion position, corresponding to the recess 55f provided at the tip of the engaging claw 55b.

[0150] Just before the exposure head 4 completes its sliding motion in the direction of arrow B, the tip of the engaging claw 55b interferes with the protrusion 69f, causing the engaging claw 55b to elastically deform, and the sliding force of the exposure head 4 increases once compared to the force immediately before the interference. Thereafter, the recess 55f of the engaging claw 55b reaches the protrusion 69f, and the recess 55f and the protrusion 69f engage, causing the sliding force of the exposure head 4 to decrease.

[0151] In other words, when the exposure head 4 is moved in the extension direction relative to the lifting duct 69, the engaging claw 55b undergoes elastic deformation before the recess 55f and the protrusion 69f engage, thereby changing the operating force required to move the exposure head 4 in the extension direction. This rapid increase or decrease in the sliding force of the exposure head 4 provides a click sensation that indicates the completion of the sliding operation of the exposure head 4. In this way, the elastic deformation of the engaging claw 55b until the recess 55f of the engaging claw 55b and the protrusion 69f of the engaging hole 69b engage changes the sliding force of the exposure head 4, clearly indicating that the exposure head 4 has been installed.

[0152] As mentioned above, as shown in Figures 33 and 34, the positioning pins 45F and 45B of the exposure head 4 are auxiliaryly fitted to the auxiliary fitting portions 30h and 30i of the cartridge tray 30 at their lower end circumferential surfaces. This fitting is performed simultaneously by the sliding operation of the exposure head 4 in the direction of arrow B, as shown in Figures 40 and 44.

[0153] In this embodiment, the ground connection between the housing 54 of the exposure head 4 and the image forming apparatus 100 is also performed simultaneously by the sliding operation of the exposure head 4 in the direction of arrow B described above. The housing 54 of the exposure head 4 and the positioning pins 45F and 45B are crimped and fixed together and electrically connected.

[0154] As shown in Figure 42, the ground connection to the image forming apparatus 100 is made by the circumferential surface of the positioning pin 45F of the exposure head 4 contacting a conductive member 251 provided on the cartridge tray 30 on the apparatus side. The conductive member is electrically conductive. Specifically, the conductive member 251 is made of a thin metallic plate. Therefore, sufficient contact pressure is obtained by contact and deformation caused by the sliding motion of the exposure head 4. The conductive member 251 is electrically connected to the frame sheet metal of the image forming apparatus 100 after passing through a circuit board on which a harness (not shown), a resistor element for noise reduction, and a capacitor are mounted.

[0155] In this way, the positioning pin 45F of the exposure head 4 can be electrically connected to the conductive member 251 by sliding, thereby connecting the exposure head 4 to ground. This makes it possible to easily connect the exposure head 4 to ground or the like to suppress the generation of radiated noise such as electromagnetic waves. In other words, stable grounding characteristics can be obtained simply by sliding the exposure head 4 to the lifting duct 69.

[0156] (Bonding and sealing of the housing and circuit board, and the housing and lens array) The exposure head 4 is manufactured by assembling and fixing a substrate 50 and a lens array 52 into a housing 54 and then sealing it. The bonding and sealing of the housing 54 and the housing 54 and the lens array 52 in this manufacturing method of the exposure head 4 will be explained in detail with reference to Figures 50 to 57.

[0157] The substrate 50, which is inserted into and positioned in the second opening 54b of the housing 54, is temporarily fixed by bonding the extended portions 54L and 54R of the housing 54 to the LR direction (short side direction of the substrate 50) edge portion of the lower surface of the substrate 50 with the fifth adhesive 77c (see Figures 50 and 51). In this embodiment, the fifth adhesive 77c is an acrylic-based photocurable resin that hardens by UV irradiation, as it has the characteristic of being able to harden in a short time even at room temperature.

[0158] The fifth adhesive 77c is preferably bonded to the substrate 50 at positions approximately symmetrical to the LR center (the short-side center of the substrate 50), and at approximately equal intervals in the FB direction (the longitudinal direction of the substrate 50). In the FB direction, it is desirable to bond at three or more points to correct the warping of the substrate 50; in this embodiment, eight points are bonded. Furthermore, the bonding positions at both ends in the FB direction are preferably located outside the image-forming region in order to effectively correct the warping of the substrate 50 within the image-forming region.

[0159] The lens array 52, which is inserted into and positioned in the first opening 54a formed in the flat portion 54U of the housing 54, is also temporarily fixed by bonding the flat portion 54U and the side surface of the lens array 52 with the sixth adhesive 77d (see Figures 52 and 53). In this embodiment, the sixth adhesive 77d is an acrylic-based photocurable resin, similar to the temporary fixing of the substrate 50.

[0160] The sixth adhesive 77d is preferably applied at positions approximately symmetrical to the LR center of the lens array 52 (the short-side center of the lens array 52), and at approximately equal intervals in the FB direction (the longitudinal direction of the lens array 52). In the FB direction, it is desirable to apply adhesive at three or more points to correct the warping of the lens array 52; in this embodiment, nine points are applied. Furthermore, the adhesive positions at both ends in the FB direction are preferably located outside the image-forming region in order to effectively correct the warping of the lens array 52 within the image-forming region.

[0161] Thus, by using an adhesive that can harden quickly even at room temperature for the temporary fixing of the housing 54 to the substrate 50 and the housing 54 to the lens array 52, it is possible to shorten the time required to hold each component with tools, etc. However, the elastic modulus of the acrylic photocurable resin used in the fifth adhesive 77c and the sixth adhesive 77d is about several hundred [MPa], which is inferior in rigidity compared to general resin materials (several GPa) and metal materials (several tens [GPa] to several hundred [GPa]). In addition, the glass transition point of the acrylic photocurable resin is several tens [°C], and the coefficient of linear expansion at temperatures above the glass transition point can be several hundred [ppm / °C]. As a result, there is a risk that the positional relationship between the housing 54 and the substrate 50 and the housing 54 and the lens array 52 may change due to the temperature rise caused by the exposure head 4 and other heat sources inside the image forming apparatus 100. Therefore, in this embodiment, after temporary fixing with an acrylic photocurable resin, permanent fixing is performed with a thermosetting resin that has the characteristics of a higher modulus of elasticity, a higher glass transition temperature, and a lower coefficient of linear expansion.

[0162] In the temporarily fixed housing 54 and substrate 50, the extensions 54L and 54R of the housing 54 and the LR direction edges of the lower surface of the substrate 50 are bonded together with the first adhesive 77a to permanently fix them in place (see Figures 50 and 51). In this embodiment, the first adhesive 77a is an epoxy-based thermosetting resin having an elastic modulus of several tens [GPa] after curing, a glass transition temperature of around 100 [°C], and a coefficient of linear expansion of several tens [ppm / °C] in the range of actual operating ambient temperatures. The thermosetting resin is cured by heating it in an oven at 100 [°C] for several hours.

[0163] The first adhesive 77a is preferably bonded to the substrate 50 at positions approximately symmetrical to the LR center, and at approximately equal intervals in the FB direction (longitudinal direction of the substrate 50). In order to permanently correct the warping of the substrate 50, it is desirable to bond at least three points in the FB direction, and in this embodiment, a total of seven points are bonded, one point between each of the fifth adhesives 77c.

[0164] Furthermore, the two adjacent fifth adhesives 77c may be bonded at multiple points using the first adhesive 77a. In addition, to reduce the influence of the fifth adhesive 77c, which undergoes significant thermal deformation when heated, the first adhesive 77a may be bonded at a position a few millimeters closer to the fifth adhesive 77c than a strictly equal spacing in the FB direction. In this case, it is even better to bond the first adhesive 77a at a position where it sandwiches the fifth adhesive 77c from both sides in the FB direction. Although the configuration shows the first adhesive 77a bonding the inside of the fifth adhesive 77c in the FB direction, the configuration may also show the first adhesive 77a bonding the outside.

[0165] In the temporarily fixed housing 54 and lens array 52, the flat portion 54U and the side surface of the lens array 52 are permanently fixed by bonding with the third adhesive 77b (see Figures 52 and 53). In this embodiment, the third adhesive 77b is an epoxy-based thermosetting resin, similar to the permanent fixing of the substrate 50. It is desirable that the third adhesive 77b be bonded at positions approximately symmetrical to the LR center of the lens array 52 (the short-side center of the lens array 52), and that in the FB direction (the longitudinal direction of the lens array 52), it be bonded at approximately equal intervals. In the FB direction, it is desirable to bond at three or more points in order to permanently correct the warping of the lens array 52, and in this embodiment, a total of eight points are bonded, one point between each of the sixth adhesives 77d.

[0166] Furthermore, the third adhesive 77b may be used to bond two adjacent sixth adhesives 77d at multiple points. In addition, to reduce the influence of the sixth adhesive 77d, which undergoes significant thermal deformation when heated, the third adhesive 77b may be bonded at a position a few millimeters closer to the sixth adhesive 77d than a strictly equal spacing in the FB direction. In this case, it is even better to bond the third adhesive 77b so that it sandwiches the sixth adhesive 77d from both sides in the FB direction. Although the configuration shows the third adhesive 77b bonding the inside of the sixth adhesive 77d in the FB direction, the configuration may also show the third adhesive 77b bonding the outside.

[0167] As described above, in bonding the housing 54 to the substrate 50 and the housing 54 to the lens array 52, temporary fixing is performed with a photocurable resin, followed by permanent fixing with a thermosetting resin. This makes it possible to easily assemble an exposure head 4 that has high positional accuracy, high rigidity, and is resistant to temperature changes.

[0168] Various electrical components (e.g., driver ICs, resistors, capacitors, thermistors, FFC connectors 57, etc.) are mounted on the underside of the substrate 50. Thermosetting resins and photocuring resins shrink during curing, and if temperature changes occur after curing, they expand and contract due to heat, generating stress and strain in the attached components. If these adhere to electrical components, they may damage the electrical components or deform the substrate 50, potentially worsening the imaging characteristics. Therefore, in this embodiment, the bonding positions of the first adhesive 77a and the fifth adhesive 77c in the FB direction (longitudinal direction of the substrate 50) are offset from a strictly equal spacing pitch to position them away from the electrical components, thereby preventing damage to the electrical components and deterioration of the imaging characteristics.

[0169] When inserting or removing the FFC 58 from the FFC connector 57, the insertion / removal resistance of the FFC 58 and the gripping force of the housing 54 may deform the exposure head 4, potentially causing damage or deterioration of imaging characteristics. Therefore, in this embodiment, the vicinity of both ends of the FFC connector 57 in the FB direction is bonded with adhesive so that the resulting load can be supported by the housing 54.

[0170] Here, if the adhesives at both ends are made only of the first adhesive 77a, the arrangement pitch of the fifth adhesive 77c in the FB direction (longitudinal direction of the substrate 50) will be wide, which may reduce the rigidity during temporary fixing. For this reason, it is desirable to use the first adhesive 77a at one end and the fifth adhesive 77c at the other end. Also, it is desirable that the distance between both adhesives and the ends of the FFC connector 57 be within the range of 2 to 10 [mm]. In this embodiment, the F-direction end is bonded with the first adhesive 77a and the B-direction end with the fifth adhesive 77c, but it is also possible to bond the F-direction end with the fifth adhesive 77c and the B-direction end with the first adhesive 77a.

[0171] Furthermore, at least one adhesive point in the FB direction (longitudinal direction of the lens array 52) of the third adhesive 77b that permanently fixes the housing 54 and the lens array 52 is provided above the FFC connector 57 in the FB direction. This prevents deformation of the housing 54 when gripping the housing 54 during insertion or removal of the FFC 58.

[0172] In this fixed housing 54 and substrate 50, the extensions 54L and 54R of the housing 54 and the edges of the substrate 50 in the LR direction (short side direction of the substrate 50) on the lower surface of the substrate 50 are bonded and sealed by the second adhesive 59a (see Figures 54 and 55). The second adhesive 59a is applied over the first adhesive 77a and the fifth adhesive 77c. In this embodiment, the second adhesive 59a is a silicone-based moisture-curing resin with lower viscosity compared to the acrylic-based photocurable resin and epoxy-based thermosetting resin described above. The second adhesive 59a is a non-thermosetting resin. By using a low-viscosity adhesive, the second adhesive 59a conforms to the shape of the first adhesive 77a and the fifth adhesive 77c, and can penetrate the gap between the extensions 54L and R of the housing 54 and the LR-direction edges of the substrate 50, completely sealing the gap. Furthermore, by using a moisture-curing resin for the second adhesive 59a, the second adhesive 59a can be easily cured in a normal temperature and humidity environment without the need for special equipment for curing.

[0173] The application of the first adhesive 77a, the second adhesive 59a, and the fifth adhesive 77c will be explained in detail with reference to Figures 58 to 61.

[0174] The first adhesive 77a and the second adhesive 59a are applied using a method in which the adhesive is dispensed from a needle 401 (see Figure 61). The adhesive is dispensed from the tip of the needle 401, and after the dispensing is complete, the needle 401 is moved to stretch the adhesive, thereby separating the adhesive from the needle 401. At this time, depending on the viscosity of the first adhesive 77a and the fifth adhesive 77c, a portion of the adhesive will maintain its stretched shape and become a pointed, elongated shape. In this embodiment, by pulling the needle 401 away from the needle 401 in the direction of F after application, at least a portion of the first adhesive 77a will become an elongated shape on the F side.

[0175] The fifth adhesive 77c is an acrylic-based photocurable resin, which is applied. In this embodiment, an air pulse type dispenser and a metal needle 401a are used for application (see Figure 58). Dispensers not shown are not limited to the air pulse type; valve type or the like may be used. Also, the needle 401a is not limited to a metal needle; a resin needle may be used.

[0176] Since the application area is the corner of the workpiece, it is preferable to apply the adhesive with the housing 54 and the needle 401a tilted relative to each other at an angle of 15° to 75°. In this embodiment, the housing 54 and the needle 401a were tilted relative to each other at an angle of 40°. After the fifth adhesive 77c is dispensed, if the needle 401a is pulled up, a protrusion will appear in the height direction, so the needle 401a is moved in the F direction before being pulled up. In this embodiment, the needle 401a is moved 3 [mm] in the F direction before being pulled up. Since the fifth adhesive 77c is an acrylic-based photocurable resin, it is cured by light irradiation using a light curing device (not shown).

[0177] After temporary fixing with the fifth adhesive 77c, permanent fixing is performed with the first adhesive 77a. In the case of the first adhesive 77a, the dispenser used for application was an air pulse type, and the needle 401b was a metal needle (see Figure 59). Similar to the fifth adhesive 77c, the dispenser is not limited to an air pulse type but may be of other types such as a valve type. Similarly, the needle 401b is not limited to a metal needle but may be a resin needle. Likewise, in the case of the first adhesive 77a, since the application area is the corner of the workpiece, it is preferable to apply the adhesive with the housing 54 and the needle tilted relative to each other at an angle of 15° to 75°. In this embodiment, the housing 54 and the needle were tilted relative to each other at an angle of 35°.

[0178] As shown in Figure 66, if the needle 401b is pulled up after the first adhesive 77a is dispensed, a protruding shape in the height direction will appear on the first adhesive 77a. Therefore, the needle 401b is moved in the F direction before being pulled up. In this embodiment, the needle 401b is moved 5 mm in the F direction before being pulled up. This results in a pointed, elongated shape 402 for part of the adhesive. After the application of the first adhesive 77a, the first adhesive 77a is cured by heating in an oven at 100°C for several hours. Due to the high viscosity of the first adhesive 77a, it hardens while maintaining its shape after application.

[0179] As described above, in the fixed housing 54 and substrate 50, the extensions 54L and 54R of the housing 54 and the LR direction edges of the lower surface of the substrate 50 are bonded and sealed by the second adhesive 59a. The second adhesive 59a is applied from side F to side B. The second adhesive 59a is dispensed at the application start position on side F. At the start of dispensing, the amount of the second adhesive 59a dispensed at the beginning may vary, so application is started only after the adhesive has been dispensed completely. Specifically, the application operation is initiated after a certain period of time has elapsed since the start of dispensing. In this embodiment, the application operation is initiated 0.2 seconds after the start of dispensing. The time from dispensing to the start of application varies depending on the viscosity of the material and the application method, and it is necessary to adjust each time accordingly. By performing the above operation, a larger amount of material will be applied at the application start position. The application operation is performed by moving from side F to side B at a constant speed. This seals the gap.

[0180] Figure 67 shows the dispensing state of the second adhesive 59a. In this embodiment, the needle 401c remains stationary at the dispensing start position and dispenses for 0.2 seconds, creating a coated reservoir 403 called a bead. At the start of dispensing, the initial amount of adhesive may vary, so it is preferable to set a time to sufficiently form the bead (coated reservoir 403). For this reason, a coated reservoir shape is created at the dispensing start position.

[0181] Once a bead (coating pool 403) is formed, the second adhesive 59a is applied by moving the needle 401c relative to the workpiece. In this embodiment, the needle 401c is moved while the housing 54 is fixed. Since the second adhesive 59a is applied over the first adhesive 77a and the fifth adhesive 77c, sealing defects are likely to occur due to the adhesive shape of the first adhesive 77a and the fifth adhesive 77c. Therefore, as shown in Figures 67(b) and 67(c), sealing defects can be prevented by starting the application of the second adhesive 59a from the portion of the first adhesive 77a with a cut-off shape 402.

[0182] Figure 68 shows a schematic diagram illustrating the occurrence of gaps in application 404 when this embodiment is not applied. When this embodiment is not applied, a gap is created at the bottom of the adhesive cutting shape 402, resulting in poor adhesion. As described above, the second adhesive 59a is applied by moving the needle 401c from side F to side B, ensuring that the gap is reliably sealed even if the viscosity of the first adhesive 77a and the fifth adhesive 77c changes. In this embodiment, the adhesive cutting shape 402 of the first adhesive 77a is created in the direction of F, and the second adhesive 59a is applied from side F to side B, but this is not the only way to do so. For example, the same effect can be obtained by creating the adhesive cutting shape 402 of the first adhesive 77a in the direction of B, and applying the second adhesive 59a from side B to side F.

[0183] In the fixed housing 54 and lens array 52, the flat portion 54U and the side surface of the lens array 52 are bonded and sealed by the fourth adhesive 59b (see Figures 56 and 57). The fourth adhesive 59b is applied over the third adhesive 77b and the sixth adhesive 77d. In this embodiment, the fourth adhesive 59b is a silicone-based moisture-curing resin, similar to the sealing of the substrate 50. The fourth adhesive 59b is a non-thermosetting resin. By using a low-viscosity adhesive, the fourth adhesive 59b conforms to the shape of the third adhesive 77b and the sixth adhesive 77d, and can penetrate the gap between the flat portion 54U and the side surface of the lens array 52, completely sealing the gap. Furthermore, by using a moisture-curing resin for the fourth adhesive 59b, the fourth adhesive 59b can be easily cured in a normal temperature and humidity environment without the need for special equipment for curing.

[0184] The application of the third adhesive 77b, the fourth adhesive 59b, and the sixth adhesive 77d will be explained in detail with reference to Figures 62 to 65.

[0185] For the application of the third adhesive 77b and the sixth adhesive 77d, the same application method as for the first adhesive 77a and the fifth adhesive 77c is used, in which the adhesive is dispensed from the needle 401 (see Figure 65). The respective adhesives are dispensed from the tip of the needle 401, and after dispensing is complete, the needle 401 is moved to stretch the adhesive, thereby separating the adhesive from the needle 401. Similar to the first adhesive 77a and the fifth adhesive 77c, depending on the viscosity of the third adhesive 77b and the sixth adhesive 77d, a portion of the adhesive will maintain its stretched shape and become a pointed, elongated shape. In this embodiment, by pulling the needle 401 away from the needle 401 in the direction of F after application, at least a portion of the third adhesive 77b will become an elongated shape on the F side.

[0186] The sixth adhesive 77d is an acrylic-based photocurable resin, which is applied. In this embodiment, an air pulse type dispenser and a metal needle 401d are used for application (see Figure 62). Dispensers not shown are not limited to the air pulse type; valve type or the like may be used. Similarly, the needle 401d is not limited to a metal needle; a resin needle may be used.

[0187] Since the application area is the corner of the workpiece, it is preferable to apply the adhesive with the housing 54 and the needle 401d tilted relative to each other at an angle of 15° to 75°. In this embodiment, the application was performed with the housing 54 and the needle 401d tilted relative to each other at an angle of 45°. After the sixth adhesive 77d is dispensed, if the needle 401d is pulled up, a protrusion will appear in the height direction, so the needle 401d is moved in the F direction before being pulled up. Since the sixth adhesive 77d is an acrylic-based photocurable resin, it is cured by light irradiation using a light curing device (not shown).

[0188] After temporary fixing with the sixth adhesive 77d, permanent fixing is performed with the third adhesive 77b. For the third adhesive 77b, an air-pulse type dispenser and a metal needle 401e were used for application (see Figure 63). Similar to the sixth adhesive 77d, the dispenser may be of other types, such as a valve type, rather than an air-pulse type. Similarly, the needle 401e may be a resin needle rather than a metal needle.

[0189] In the case of the third adhesive 77b, since the application area is the corner of the workpiece, it is preferable to apply the adhesive with the housing 54 and the needle tilted relative to each other at an angle of 15° to 75°. In this embodiment, the housing 54 and the needle were tilted relative to each other at an angle of 45°. As shown in Figure 66, if the needle 401 is pulled up after dispensing, a protruding shape will appear in the height direction of the third adhesive 77b, so the needle 401e is moved in the F direction before being pulled up. In this embodiment, the needle 401e is moved 5 [mm] in the F direction before being pulled up. This results in a pointed, elongated shape 402 for part of the adhesive. After application of the third adhesive 77b, the third adhesive 77b is cured by heating in an oven at 100 [°C] for several hours. Due to the high viscosity of the third adhesive 77b, it hardens while maintaining its shape after application.

[0190] As described above, in the fixed housing 54 and lens array 52, the flat portion 54U and the side surface of the lens array 52 are bonded and sealed by the fourth adhesive 59b. The fourth adhesive 59b is also applied from side F to side B. The fourth adhesive 59b is dispensed at the application start position on side F. At the start of dispensing, the amount of the fourth adhesive 59b dispensed at the beginning may vary, so application is started only after it has been dispensed completely. Specifically, the application operation is started after a certain period of time has elapsed since the start of dispensing. In this embodiment, the application operation is started 0.25 seconds after the start of dispensing. The time from dispensing to the start of application varies depending on the viscosity of the material and the application method, and it is necessary to adjust each time accordingly. By performing the above operation, a larger amount of material will be applied at the application start position. The application operation is performed by moving from side F to side B at a constant speed. This seals the gap.

[0191] Figure 67 shows the dispensing state of the fourth adhesive 59b. In this embodiment, the needle 401f is stationary at the dispensing start position and dispensing for 0.25 seconds to create a coating pool 403. At the start of dispensing, the initial amount of adhesive may vary, so it is preferable to set a time to sufficiently form a bead (coating pool 403). For this reason, a coating pool shape is created at the dispensing start position.

[0192] Once a bead (coating pool 403) is formed, the fourth adhesive 59b is applied by moving the needle 401f relative to the workpiece. In this embodiment, the needle 401f is moved while the housing 54 is fixed. Since the fourth adhesive 59b is applied over the third adhesive 77b and the sixth adhesive 77d, sealing defects are likely to occur due to the shape of the adhesives of the third adhesive 77b and the sixth adhesive 77d. Therefore, as shown in Figures 67(b) and 67(c), sealing defects can be prevented by starting the application of the fourth adhesive 59b from the elongated portion of the third adhesive 77b and the sixth adhesive 77d.

[0193] As described above, the fourth adhesive 59b is applied by moving the needle from side F to side B, ensuring that the gap is reliably sealed even if the viscosity of the third adhesive 77b and the sixth adhesive 77d changes. In this embodiment, the third adhesive 77b is cut off in the direction of F, and the fourth adhesive 59b is applied from side F to side B, but this is not the only way to do so. For example, the same effect can be obtained by creating the cut-off shape 402 of the third adhesive 77b in the direction of B, and applying the fourth adhesive 59b from side B to side F.

[0194] (modified version) The configuration of the present invention is not limited to the embodiments described above. In the example described above, a tandem-intermediate transfer type 4-color full-color printer was used as an example, but the image forming apparatus 100 may also be a direct transfer type that transfers the toner image from the photosensitive drum 2 to the recording paper P without using an intermediate transfer belt 9, for example. Furthermore, the image forming apparatus 100 may be a 5-color or more full-color printer using one-color monocolor or spot color toner. In that case, the image forming apparatus 100 may be configured to have exposure heads 4 corresponding to the number of colors.

[0195] In the embodiment described above, an elastic material such as sponge or rubber made of urethane or silicone was used as the sealing member 207 between the opening 64 formed by the cartridge tray 30 and the lifting duct 69 and the opening 61 of the duct unit. However, the sealing member 207 may also be made of a resin sheet such as PET, modified PPE, or PE, which can be elastically deformed to seal the gaps in each opening. Furthermore, although the sealing member 207 was configured to be placed on the duct unit 60, the sealing member 207 may also be placed on, for example, the cartridge tray 30 or the lifting duct 69, or a configuration in which it is placed on multiple parts may be selected.

[0196] Furthermore, although the third opening 201 and fourth opening 202 of the duct unit 60 are connected to an opening 64 (first opening 73 and second opening 74) formed by the cartridge tray 30 and the lifting duct 69, the configuration is not limited to this. For example, instead of opening 64, the lifting duct 69 may be provided with a first opening 73 and a second opening 74, respectively, and the third opening 201 and fourth opening 202 of the duct unit 60 may be directly connected to the first opening 73 and the second opening 74, respectively.

[0197] In the embodiment described above, the duct unit 60 is configured to have one opening that includes both the third opening 201 and the fourth opening 202, but it is also possible to have only one of the openings. In that case, either the first opening 73 or the second opening 74 on the image forming apparatus 100 side can be brought into close contact with the third opening 201 or the fourth opening 202 via the sealing member 207. At this time, one of the first opening 73 or the second opening 74 on the image forming apparatus 100 side can be brought into close contact, and the other opening can be extended to a space where there is no risk of toner scattering.

[0198] In the embodiment described above, a configuration was shown in which the cooling duct 75 (see Figure 25) is formed between the duct unit 60 and the cartridge tray 30 or the lifting duct 69. However, it is not necessarily required that the cooling duct 75 be formed by the duct unit 60. In that case, the cooling duct 75 may be formed by the cartridge tray 30 or the lifting duct 69 alone.

[0199] In the embodiment described above, the intake port 203 is configured to directly draw in air from outside the image forming apparatus 100, and the exhaust port 204 is configured to directly exhaust air to the outside of the apparatus. However, it is not necessary to adopt such a configuration. For example, the intake port 203 may be configured to draw in relatively cool air from a space without heat sources such as the sheet cassette 12. Similarly, the exhaust port 204 may be configured to exhaust air to a space where there is no influence from heat inside the image forming apparatus 100.

[0200] Furthermore, the intake fan 62 and exhaust fan 63 are not necessarily required; the system may be configured to circulate airflow through the pressure difference between the exposure cooling airflow and the outside air without either or both of them.

[0201] The vertical orientation of the units and components has been described in accordance with the arrangement of each unit in the cross-sectional view of the image forming apparatus 100 shown in Figure 2. However, a unit arrangement in which the photosensitive drum 2 is positioned above the intermediate transfer belt 9, and the exposure head 4 is positioned above that, is also possible, such as in the top exposure method in which the photosensitive drum 2 is exposed from approximately above. In that case, the vertical orientations described in the above embodiment are all reversed, and the duct unit 60 will be configured to descend just before the assembly position.

[0202] In the embodiment described above, the harness opening 252 is provided on the drum unit 23 side as an example (see Figure 39), but it is not limited to this, and it may also be provided on the developing unit 24 side. By providing the harness opening 252 on the developing unit 24 side, which is located near the exposure head 4, it is possible to prevent it from affecting the airflow along the drum unit 23.

[0203] In the above-described embodiment, an example was given in which engaging claws 55b and 55c are provided on the housing support member 55 that constitutes the exposure head 4. However, engaging claws may also be provided on the components on the image forming apparatus 100 side. In that case, L-shaped engaging claws may be provided on the lifting duct 69, and engaging holes that engage with the engaging claws may be provided on the housing support member 55. In the above-described embodiment, an example was given in which a recess 55f is provided on the housing support member 55 that constitutes the exposure head 4. However, recesses may also be provided on the components on the image forming apparatus 100 side. In that case, a recess may be provided on the lifting duct 69, and a protrusion that engages with the recess may be provided on the housing support member 55.

[0204] In the embodiment described above, the sliding motion for mounting the exposure head 4 was performed from the front to the rear of the image forming apparatus 100, but it may also be configured to slide from the rear to the front. In that case, the shapes of the engaging claws and engaging holes should be reversed in the front-to-back direction.

[0205] In the embodiment described above, the positioning of the photosensitive drum of the exposure head 4 in the two-axis direction and the ground connection were performed using the front positioning pin 45F, but this may also be done using the rear positioning pin 45B. Furthermore, the ground connection may be performed using both the front and rear positioning pins 45F and 45B.

[0206] In the above-described embodiment, the positions of the housing 54 and the substrate 50, and the housing 54 and the lens array 52 were adjusted. However, it is also possible to position the housing 54 and the substrate 50 by abutting them together, and adjust only the position of the housing 54 and the lens array 52. ​​Conversely, it is also possible to position the housing 54 and the lens array 52 by abutting them together, and adjust only the position of the housing 54 and the substrate 50. When positioning by abutting, the elastic modulus of the adhesive may be low, so the use of thermosetting resin may be limited to the adhesive portion of the parts to be adjusted.

[0207] Furthermore, although the substrate 50 was directly bonded to the housing 54, the substrate 50 may also be used as a unitized substrate assembly, fixed to a long heat sink or reinforcing member made of aluminum, iron, resin, etc. In this case, the substrate assembly and the housing 54 may be bonded together with the first adhesive 77a, the fifth adhesive 77c, and the second adhesive 59a, thereby indirectly fixing the substrate 50.

[0208] In this embodiment, the housing 54 and the substrate 50, and the housing 54 and the lens array 52 are bonded at multiple points using a thermosetting resin having a high modulus of elasticity. This makes it possible to achieve both high imaging characteristics and high rigidity in the exposure apparatus (exposure head 4). Furthermore, it becomes possible to achieve good sealing without sealing defects.

Claims

1. A long-shaped substrate assembly having at least one substrate on which light-emitting elements are arranged, A long lens array that focuses the light emitted from the light-emitting element onto the surface of the photoreceptor, The system comprises a housing that supports the aforementioned circuit board assembly, The longitudinal ends of the substrate assembly and the housing are bonded at multiple points using a first adhesive made of thermosetting resin. The gap between the longitudinal end of the substrate assembly and the housing is characterized in that at least a portion of the gaps between the multiple first adhesives is bonded by a second adhesive made of a non-thermosetting resin. Exposure apparatus.

2. A long-shaped substrate assembly having at least one substrate on which light-emitting elements are arranged, A long lens array that focuses the light emitted from the light-emitting element onto the surface of the photoreceptor, The housing supports the aforementioned lens array, The longitudinal ends of the lens array and the housing are bonded at multiple points using a third adhesive made of thermosetting resin. The gap between the longitudinal end of the lens array and the housing is characterized in that at least a portion of the gaps between the plurality of third adhesives is bonded by a fourth adhesive made of a non-thermosetting resin. Exposure apparatus.

3. A long-shaped substrate assembly having at least one substrate on which light-emitting elements are arranged, A long lens array that focuses the light emitted from the light-emitting element onto the surface of the photoreceptor, The assembly comprises the substrate assembly and a housing that supports the lens array, The longitudinal ends of the substrate assembly and the housing are bonded at multiple points using a first adhesive made of thermosetting resin. The gap between the longitudinal end of the substrate assembly and the housing is bonded by a second adhesive made of a non-thermosetting resin, at least a portion of the gaps between the multiple first adhesives. The longitudinal ends of the lens array and the housing are bonded at multiple points using a third adhesive made of thermosetting resin. The gap between the longitudinal end of the lens array and the housing is characterized in that at least a portion of the gaps between the plurality of third adhesives is bonded by a fourth adhesive made of a non-thermosetting resin. Exposure apparatus.

4. The longitudinal ends of the substrate assembly and the housing are bonded at multiple locations using a fifth adhesive made of a photocurable resin. The exposure apparatus according to claim 1 or 3.

5. The longitudinal ends of the lens array and the housing are bonded at multiple locations using a sixth adhesive made of a photocurable resin. The exposure apparatus according to claim 2 or 3.

6. The multiple first adhesives are characterized by adhering to positions that are approximately equally spaced in the longitudinal direction of the substrate assembly. The exposure apparatus according to claim 1 or 3.

7. The multiple first adhesives are characterized by being applied at positions that are substantially symmetrical with respect to the short-side center of the substrate assembly. The exposure apparatus according to claim 1 or 3.

8. The first adhesive is characterized by adhering to an electrical component mounted on the side of the substrate opposite to the side on which the light-emitting element is mounted, at a position avoiding the longitudinal direction of the substrate assembly. The exposure apparatus according to claim 1 or 3.

9. The third adhesive, applied to multiple locations, is characterized by being applied at positions that are substantially equally spaced in the longitudinal direction of the lens array. The exposure apparatus according to claim 2 or 3.

10. The third adhesive, applied to multiple locations, is characterized by being applied to positions that are substantially symmetrical in the short-side direction of the lens array. The exposure apparatus according to claim 2 or 3.

11. The fifth adhesive, applied to multiple locations, is characterized by being bonded at positions approximately equally spaced in the longitudinal direction of the substrate assembly. The exposure apparatus according to claim 4.

12. The fifth adhesive, applied to multiple locations, is characterized by being applied to positions that are substantially symmetrical in the short-side direction of the substrate assembly. The exposure apparatus according to claim 4.

13. The fifth adhesive, applied to multiple locations, is characterized by adhering to electrical components mounted on the substrate on the side opposite to the side on which the light-emitting element is mounted, at positions that avoid the longitudinal direction of the substrate assembly. The exposure apparatus according to claim 4.

14. The sixth adhesive, applied to multiple locations, is characterized by being applied at positions that are approximately equally spaced in the longitudinal direction of the lens array. The exposure apparatus according to claim 5.

15. The plurality of the sixth adhesives are characterized in that they are bonded to positions that are substantially symmetrical in the short direction of the lens array. The exposure apparatus according to claim 5.

16. The aforementioned circuit board is provided with a connector. The third adhesive application site is provided within the cross-sectional area of ​​the connector that is perpendicular to the longitudinal direction of the substrate assembly. The exposure apparatus according to claim 2 or 3.

17. The aforementioned circuit board is provided with a connector. The vicinity of one end of the connector in the longitudinal direction of the substrate assembly is bonded with the first adhesive. The vicinity of the other end of the connector is bonded with the fifth adhesive, characterized in that The exposure apparatus according to claim 4.

18. The first adhesive and the fifth adhesive are characterized in that they are separated from the connector. The exposure apparatus according to claim 17.

19. The second adhesive is characterized by being applied so as to cover at least a portion of the first adhesive and the fifth adhesive. The exposure apparatus according to claim 1 or 3.

20. The fourth adhesive is characterized by being applied so as to cover at least a portion of the third adhesive and the sixth adhesive. The exposure apparatus according to claim 2 or 3.

21. The second adhesive is characterized by being a moisture-curing resin. The exposure apparatus according to claim 1 or 3.

22. The fourth adhesive is characterized by being a moisture-curing resin. The exposure apparatus according to claim 2 or 3.

23. The light-emitting element is characterized by being an organic EL. An exposure apparatus according to any one of claims 1 to 3.

24. A method for manufacturing an exposure apparatus comprising: an elongated substrate assembly having at least a substrate on which light-emitting elements are arranged; an elongated lens array for focusing light emitted from the light-emitting elements onto the surface of a photoreceptor; and a housing for supporting the substrate assembly, The substrate is attached to the housing by a first adhesive made of thermosetting resin, with the adhesive being applied in such a way that a portion of it forms an elongated shape. In the gap between the longitudinal end of the substrate assembly and the housing, a second adhesive made of a non-thermosetting resin is applied starting from the elongated shape of the first adhesive, thereby bonding a portion of the first adhesive to the housing. A method for manufacturing an exposure apparatus.

25. A method for manufacturing an exposure apparatus comprising: an elongated substrate assembly having at least a substrate on which light-emitting elements are arranged; an elongated lens array for focusing light emitted from the light-emitting elements onto the surface of a photoreceptor; and a housing for supporting the substrate assembly, The lens array is bonded and fixed to the housing by applying a third adhesive made of thermosetting resin, such that a portion of the third adhesive takes on an elongated shape. In the gap between the longitudinal end of the lens array and the housing, a fourth adhesive made of a non-thermosetting resin is applied starting from the elongated shape of the third adhesive, thereby bonding a portion of the third adhesive to the housing. A method for manufacturing an exposure apparatus.

26. A method for manufacturing an exposure apparatus comprising: an elongated substrate assembly having at least a substrate on which light-emitting elements are arranged; an elongated lens array for focusing light emitted from the light-emitting elements onto the surface of a photoreceptor; and a housing for supporting the substrate assembly, The substrate is attached to the housing by a first adhesive made of thermosetting resin, with the adhesive being applied in such a way that a portion of it forms an elongated shape. In the gap between the longitudinal end of the substrate assembly and the housing, a second adhesive made of a non-thermosetting resin is applied starting from the elongated shape of the first adhesive, thereby bonding a portion of the first adhesive to the housing. The lens array is bonded and fixed to the housing by applying a third adhesive made of thermosetting resin, such that a portion of the third adhesive takes on an elongated shape. In the gap between the longitudinal end of the lens array and the housing, a fourth adhesive made of a non-thermosetting resin is applied starting from the elongated shape of the third adhesive, thereby bonding a portion of the third adhesive to the housing. A method for manufacturing an exposure apparatus.

27. A photoreceptor having a photosensitive layer on its surface, A charger that uniformly charges the surface of the photoreceptor, An exposure apparatus according to any one of claims 1 to 3, which forms an electrostatic latent image by exposing the surface of the charged photoreceptor, A developing device that develops the electrostatic latent image to form a toner image on the surface of the photoreceptor, A transfer means for transferring the toner image onto recording paper, A fuser that fixes the transferred toner image onto the recording paper, characterized in that it comprises Image forming apparatus.

Images