Image formation apparatus

Abstract

To provide an image formation apparatus capable of cooling an exposure unit and a developing unit with air drawn in by an intake fan and exhausting the air after cooling the exposure unit and the developing unit, without securing a wide space inside the apparatus body.SOLUTION: An exposure unit and a developing unit are cooled respectively by an exposure cooling airflow passing through a first path and a developing cooling airflow passing through a second path. In an exhaust duct 206 of a duct unit 60, air after exposure cooling is merged with air after developing cooling, and the air after exposure cooling and the air after developing cooling are exhausted from the exhaust duct 206 by an exhaust fan 63. That is, in the duct unit 60 which forms the exposure cooling airflow by drawing air with an intake fan 62 in order to cool the exposure unit 4, the exhaust duct 206 for exhausting the air after exposure cooling is shared as a duct for exhausting the air after developing cooling. Consequently, there is no need to secure a wide space inside the apparatus body.SELECTED DRAWING: Figure 16

Description

[Technical Field]

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

[0002] In an image forming apparatus, an electrostatic latent image is formed on a charged photosensitive drum by an exposure unit, which includes multiple light-emitting elements such as LEDs or organic electroluminescent devices arranged along the rotational axis of the photosensitive drum. The exposure unit is preferably located close to the photosensitive drum, and therefore is located close to a developer unit that develops the electrostatic latent image formed on the photosensitive drum into a toner image. However, the toner contained in the developer unit is sensitive to heat and is easily affected by the heat generated by the exposure unit in response to the light emitted by the light-emitting elements. Therefore, to prevent the toner from being affected by the heat generated by the exposure unit, air is drawn in from outside the image forming apparatus body to cool the exposure unit and the developer unit. Patent Document 1 proposes an image forming apparatus that has separate exhaust ducts for cooling the exposure unit and the developer unit, respectively, which exhaust air after cooling the exposure unit and the developer unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-132358 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the past, because an exhaust duct for cooling the exposure unit and an exhaust duct for cooling the developer unit were provided separately, it was necessary to secure space within the device body to install these ducts, which could result in the image forming device becoming larger.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide an image forming apparatus that can cool an exposure unit and a developing unit using air drawn in from an intake fan, without requiring a large space inside the apparatus body, and that can exhaust the air after cooling the exposure unit and the developing unit. [Means for solving the problem]

[0006] an exposure unit having a plurality of light-emitting elements arranged in the longitudinal direction and configured to form a latent image on the charged surface of the photosensitive member by illuminating the plurality of light-emitting elements; a development unit that develops the latent image formed on the photosensitive member with a developer; a first intake fan; a first intake duct that guides the air drawn by the first intake fan along at least a portion of the exposure unit to a first path through which the air drawn by the first intake fan flows to cool the exposure unit; a second intake fan; a second intake duct that guides the air drawn by the second intake fan along at least a portion of the development unit to a second path through which the air drawn by the second intake fan flows to cool the development unit; an exhaust fan; and an exhaust duct that joins the air flowing through the first path and the air flowing through the second path and exhausts the air by the exhaust fan. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an image forming apparatus that can cool an exposure unit and a developing unit using air drawn in from a first intake fan and a second intake fan, and that can exhaust the air after cooling the exposure unit and the developing unit, without having to secure a large space inside the apparatus body. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an external perspective view showing an image forming apparatus according to an embodiment of the present invention; [Figure 2] FIG. 1 is a schematic diagram illustrating a configuration of an image forming apparatus. [Figure 3]FIG. 2 is a schematic diagram showing the image forming apparatus in a state where the developing sleeve and the exposure unit are retracted. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. 4 is a perspective view showing the bottom surface of the exposure unit. [Figure 7] FIG. [Figure 8] FIG. 4 is an enlarged view showing the front cover and inner door in an open state. [Figure 9] FIG. 4 is an enlarged view showing the state in which the drum unit is removed. [Figure 10] FIG. 4 is an enlarged view showing a state in which the development unit is removed. [Figure 11] FIG. 2 is a cross-sectional view showing the drum unit, the developing unit, the exposure unit, and the cartridge tray. [Figure 12] FIG. [Figure 13] FIG. 4 is a perspective view showing the cartridge tray with the inner door open. [Figure 14] FIG. 10 is a side view showing the cartridge tray with the inner door closed. [Figure 15] FIG. 4 is a side view showing the cartridge tray with the inner door open. [Figure 16] 3 is a cross-sectional view showing the exposure cooling air flow and the development cooling air flow as viewed from the CC arrow in FIG. 2; [Figure 17] 3 is a cross-sectional view showing the developer cooling air flow as viewed from the arrow AA in FIG. 2. [Figure 18] FIG. [Figure 19] FIG. 4 is a cross-sectional view showing the exposure cooling flow in the intake duct. [Figure 20] FIG. 4 is a perspective view showing the bottom surface of the cartridge tray. [Figure 21] FIG. 4 is a cross-sectional view showing the exposure cooling air flow in the exhaust duct. [Figure 22] 3 is a cross-sectional view showing a developer-cooling air flow as viewed from the arrow BB in FIG. 2; [Figure 23]FIG. 4 is a cross-sectional view showing a confluence of a development cooling air flow and an exposure cooling air flow in an exhaust duct. [Figure 24] Cross-sectional view showing two exhaust fans arranged in series. [Figure 25] Cross-sectional view showing the arrangement of one large exhaust fan. [Figure 26] FIG. 3 is a control block diagram showing a control system related to cooling of the developing unit and the exposure unit. [Figure 27] 10 is a flowchart showing a cooling process for cooling the developing unit and the exposure unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Image forming equipment] The present embodiment will be described below. First, an overview of the image forming apparatus of the present embodiment will be described with reference to FIGS. 1 to 3. As shown in FIG. 1, the image forming apparatus 100 of the present embodiment is a so-called internal discharge type image forming apparatus. That is, the image forming apparatus 100 includes a housing 100A and a document reading device 200 that reads image information of a document, and a discharge tray 21 that stacks sheets S (recording materials) discharged from the housing 100A is formed between the housing 100A and the document reading device 200. The image forming apparatus 100 forms a toner image on the sheet S in accordance with an image signal sent from the document reading device 200 or an external device (not shown) such as a personal computer.

[0010] Housing 100A (also referred to as device main body) is provided with an operation unit 46 on the front side, which has a display unit capable of displaying various information and keys for inputting various information in response to user operations. In this specification, the side on which a user stands when operating operation unit 46 to operate image forming apparatus 100 is referred to as the "front (front)," and the opposite side is referred to as the "rear (back)." Furthermore, the left side when viewing image forming apparatus 100 from the front is referred to as the "left," and the right side when viewing image forming apparatus 100 from the front is referred to as the "right."

[0011] Housing 100A is made up of a front plate provided on the front side of image forming apparatus 100, a rear plate provided on the rear side that supports each unit together with the front plate, stays connecting the front and rear plates, pillars supporting the front plate, and other metal plates, and is covered by an exterior cover that forms the exterior of image forming apparatus 100. As exterior covers, front cover 101, multiple cassette covers 103, and upper front cover 104 are arranged on the front side. In addition, side covers 105 and 106 are arranged on the left and right side sides, and a rear cover 325 is arranged on the rear side.

[0012] 2 and 3 includes four image forming units 1Y, 1M, 1C, and 1K that form toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (K). Note that the configurations of the image forming units 1Y, 1M, 1C, and 1K that form toner images of each color are almost the same, so in FIGS. 2 and 3, only the magenta image forming unit 1M is given a reference numeral, and the image forming unit 1M will be used as an example for explanation.

[0013] The image forming section 1M has two units: a drum unit 23 (also called a drum cartridge) and a developing unit 24 (also called a developing cartridge) (see FIG. 3). The drum unit 23 and developing unit 24 are supported by a cartridge tray 30 and are provided so as to be insertable into and removable from the cartridge tray 30 from the front side of the apparatus main body, with each unit being guided in the direction of the rotation axis of the photosensitive drum 2, which rotates around a rotation axis along the longitudinal direction. The drum unit 23 has the photosensitive drum 2 as a photosensitive member, a charging roller 3 that charges the photosensitive drum 2, and a drum cleaner unit (not shown).

[0014] The developing unit 24 as a developing section is disposed in a developer container that contains a developer containing toner. The developing unit 24 includes a developing sleeve 5 that supplies toner to the photosensitive drum 2 to form a toner image, and a conveying screw 7 that conveys the toner while stirring it and supplies it to the developing sleeve 5. Between the drum unit 23 and the developing unit 24 in the rotational direction of the photosensitive drum 2, an exposure unit 4 that exposes the surface of the photosensitive drum 2 to light to form an electrostatic latent image is disposed. The exposure unit 4 as an exposure section is supported by a cartridge tray 30 so as to be disposed between the drum unit 23 and the developing unit 24. One end of the cartridge tray 30 is attached to a front side plate and the other end is attached to a rear side plate in the direction of the rotation axis of the photosensitive drum 2. A duct unit 60 for cooling the exposure unit 4 is disposed below the cartridge tray 30. The cartridge tray 30 and the duct unit 60 will be described later.

[0015] An intermediate transfer belt unit 8 is disposed above the image forming stations 1Y to 1K. The intermediate transfer belt unit 8 has four primary transfer rollers 6 disposed opposite the photosensitive drums 2 of each color, and one endless intermediate transfer belt 9. Toner bottles 22Y to 22K containing replenishment toner to be supplied to the developing units 24 are provided above the intermediate transfer belt unit 8 so as to be detachable from a toner supply mechanism (not shown). The toner supply mechanism supplies the appropriate amount of toner from the toner bottles 22Y to 22K to each developing unit 24 of the corresponding image forming stations 1Y to 1K at the appropriate time. Sheet cassettes 12A and 12B containing sheets S are disposed below the image forming stations 1Y to 1K.

[0016] <Image formation process> Next, the image forming process on the sheet S in the image forming apparatus 100 will be described. In each of the image forming units 1Y to 1K, the surface of the photosensitive drum 2, which is driven to rotate by a motor (not shown), is uniformly charged by a charging roller 3 pressed against the photosensitive drum 2. Thereafter, an exposure unit 4, which is driven based on a signal of image information, irradiates the surface of the photosensitive drum 2 with light, and an electrostatic latent image is formed on the surface of the photosensitive drum 2. The electrostatic latent image formed on the photosensitive drum 1 is developed into a toner image by a developing unit 24. The developing unit 24 develops the electrostatic latent image with toner contained in a developer, and forms a toner image on the photosensitive drum 1.

[0017] In the developing unit 24, a high voltage is applied to the developing sleeve 5, and the toner, which is charged by the stirring of the conveying screw 7, is uniformly coated on the surface of the developing sleeve 5. The conveying screw 7 is rotated at a relatively high speed compared to the rotational speed of the developing sleeve 5 and the photosensitive drum 2, and as a result, the toner is evenly coated on the surface of the developing sleeve 5.

[0018] The toner image formed on the photosensitive drum 2 is primarily transferred from the photosensitive drum 2 to the intermediate transfer belt 9 by applying a primary transfer voltage to a primary transfer roller 6 disposed opposite the image forming units 1Y to 1K with the intermediate transfer belt 9 interposed therebetween. A drum cleaner unit (not shown) collects residual toner remaining on the photosensitive drum 2 after the primary transfer.

[0019] Inside the main body of the image forming apparatus 100, a sheet transport path for transporting the sheet S from bottom to top is provided on the right side. Arranged on this sheet transport path from bottom to top are a supply roller pair 13, a registration roller pair 15, a secondary transfer outer roller 16, a fixing unit 19, and a discharge roller pair 20. The secondary transfer outer roller 16 abuts against the secondary transfer inner roller 10, which is arranged inside the intermediate transfer belt 9, with a predetermined pressure across the intermediate transfer belt 9, thereby forming a secondary transfer nip portion 17.

[0020] Sheets S stored in sheet cassettes 12A and 12B are supplied one by one from either sheet cassette 12A or 12B to a sheet conveying path by driving supply roller pair 13 at a predetermined control timing. Sheet S supplied by supply roller pair 13 is conveyed to registration roller pair 15 arranged midway along the conveying path. Then, registration roller pair 15 corrects skew and timing of sheet S, and sends sheet S to secondary transfer nip portion 17. Secondary transfer nip portion 17 is formed by secondary transfer inner roller 10 and secondary transfer outer roller 16 that face each other across intermediate transfer belt 9, and is a nip portion that transfers a toner image from intermediate transfer belt 9 onto sheet S by applying a predetermined pressure and secondary transfer voltage.

[0021] The image formation processes for each color, which are processed in parallel by the image forming units 1Y to 1K for each color described above, are performed in a timed manner to sequentially superimpose the image onto the toner image of the color that was primarily transferred onto the intermediate transfer belt 9 upstream in the movement direction. As a result, a full-color toner image is formed on the intermediate transfer belt 9 and is transported to the secondary transfer nip portion 17. At the secondary transfer nip portion 17, the timing of the sheet S and the full-color toner image coincides, and secondary transfer is performed in which the toner image is transferred from the intermediate transfer belt 9 to the sheet S. The sheet S is then transported to the fuser 19, where the toner image is fixed to the sheet S by applying heat and pressure. After passing through the fuser 19, the sheet S is transported to the discharge roller pair 20 and discharged onto the discharge tray 21 by the discharge roller pair 20.

[0022] In this embodiment, the drum unit 23 and the developing unit 24 deteriorate due to repeated image formation processes and require replacement or maintenance. The drum unit 23 and the developing unit 24 are in the form of cartridges so that the user can easily insert and remove them from the main body of the device for replacement or maintenance. Figure 3 shows the arrangement of the drum unit 23, the developing unit 24, and the exposure unit 4 when inserting and removing the drum unit 23 and the developing unit 24.

[0023] 3, when inserting or removing the drum unit 23 or the developing unit 24, the developing unit 24 and the exposure unit 4 are retracted from the drum unit 23 and are spaced apart from the photosensitive drum 2, unlike the state shown in FIG. 2. This is because if the developing unit 24 and the exposure unit 4 were positioned close to the photosensitive drum 2 when inserting or removing the drum unit 23 or the developing unit 24, dynamic interference during insertion or removal of the drum unit 23 or the developing unit 24 could damage the units or make it impossible to remove them. For this reason, the user is allowed to retract the developing unit 24 and the exposure unit 4 before inserting or removing the drum unit 23 or the developing unit 24.

[0024] <Exposure unit> Next, the exposure unit 4 will be described with reference to Fig. 3 and Fig. 4 to Fig. 6. As shown in Fig. 4, the exposure unit 4 has a mounting substrate 50, a plurality of light-emitting elements 51 arranged on one side of the mounting substrate 50 in the direction of the rotation axis of the photosensitive drum 2 (longitudinal direction), and a lens assembly 52 in which a plurality of lenses that transmit light emitted from the light-emitting elements 51 are arranged. The light-emitting elements 51 are, for example, light-emitting diodes (Light Emitting Diodes) or organic electroluminescence (EL) elements. The lens assembly 52 has a plurality of lenses arranged in the direction in which the light-emitting elements 51 are arranged.

[0025] A plurality of light-emitting elements 51 and a plurality of lenses are respectively arranged on the mounting substrate 50 and the lens assembly 52 across the exposure range in the rotation axis direction of the photosensitive drum 2. Therefore, as shown in FIG. 5 , the mounting substrate 50 and the lens assembly 52 are formed in a shape that extends in the front-to-rear direction (longitudinal direction) along the rotation axis direction of the photosensitive drum 2. The mounting substrate 50 and the lens assembly 52 are held in place by being adhered to a housing 54 with high precision using an adhesive. The housing 54 is required to have high rigidity, and in this embodiment, a metal plate such as a galvanized steel plate or a cold-rolled steel plate bent into a substantially U-shaped cross section is used. The lens assembly 52 and the mounting substrate 50 are inserted into the housing 54 in order from the open side of the U and fixed with an adhesive.

[0026] The housing 54 further has a housing support member 55 formed in a substantially U-shaped cross section, which is provided integrally with the housing 54 on the side of the U-shaped opening. As shown in Fig. 6, an opening 55A that communicates between the inside and outside of the housing support member 55 is formed in the bottom of the housing support member 55 at a position facing the back surface opposite the front surface of the mounting substrate 50 in each housing 54. As described above, the exposure unit 4 is configured as an integrated head unit by the mounting substrate 50 on which the plurality of light-emitting elements 51 are mounted, the lens assembly 52 in which the plurality of lenses are arranged in parallel, the housing 54, and the housing support member 55.

[0027] As described above, by integrating the housing support member 55 and the multiple housings 54, air sent from the duct unit 60 (described later) is blown onto the mounting board 50 fixed to the housing 54 through the opening 55A between the left side wall 55L and the right side wall 55R of the housing support member 55. The air blown onto the mounting board 50 from the opening 55A of the housing support member 55 is separated from the developing unit 24 adjacent to the exposure unit 4 by the left side wall 55L and from the drum unit 23 by the right side wall 55R. Therefore, the air blown onto the mounting board 50 to cool the exposure unit 4 does not leak toward the developing unit 24 adjacent to the exposure unit 4. In this way, the air blown onto the exposure unit 4 for cooling prevents toner from the developing unit 24 from scattering inside the image forming apparatus 100.

[0028] Next, the insertion and removal of the drum unit 23 and the developing unit 24 into the apparatus main body will be described with reference to Figures 7 to 10. As shown in Figure 7, the image forming apparatus 100 is equipped with inner doors 102Y, 102M, 102C, and 102K (hereinafter collectively referred to as "inner door 102") that cover the front sides of both the drum unit 23 and the developing unit 24 that are mounted in the mounting positions of the housing 100A. The inner door 102 is a necessary member for protecting each unit and for making it difficult for the photosensitive drum 2 to be exposed to light outside the image formation process, and is disposed in a position facing the front in the direction in which the units of each color are inserted and removed so as to be able to open and close.

[0029] 8 to 10, one end of the inner door 102 is fixed to the front side of the cartridge tray 30 by a hinge, and the inner door 102 is rotatable relative to the cartridge tray 30 by the hinge. The developing unit 24 and the exposure unit 4 are retracted from the photosensitive drum 2 by a retraction mechanism that is linked to the operation of opening the inner door 102. Note that FIGS. 8 to 10 show a state in which only the inner door 102K, which opens and closes to insert and remove the drum unit 23 and developing unit 24 provided in the black image forming unit 1K, is open.

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

[0031] For example, replacement of the drum unit 23 or the developing unit 24 included in the black image forming unit 1K is performed by an operator in the following procedure. The operator opens the front cover 101 as shown in FIG. 7, and then opens the inner door 102K as shown in FIG. 8, thereby allowing the operator to remove the drum unit 23 from the apparatus main body with the developing unit 24 retracted from the photosensitive drum 2 (see FIG. 9). Alternatively, the operator can remove the developing unit 24 retracted from the photosensitive drum 2 from the apparatus main body (see FIG. 10). The operator then inserts a new drum unit 23 or developing unit 24, closes the inner door 102K, and then closes the front cover 101, thereby completing the replacement of the drum unit 23 or developing unit 24.

[0032] <Evacuation mechanism> The developing unit 24 and the exposure unit 4 are retracted from the drum unit 23 by a retraction mechanism that operates in conjunction with the opening of the inner door 102. The retraction mechanism for the developing unit 24 and the exposure unit 4 will be described with reference to FIGS. 11 to 15. As described above, the developing unit 24 and the exposure unit 4 are supported by the cartridge tray 30. The cartridge tray 30 is provided for each of the image forming sections 1Y to 1K (see FIG. 1), and supports the above-mentioned drum unit 23 and developing unit 24 so that they can be inserted and removed along the rotation axis direction of the photosensitive drum 2.

[0033] 11, 12 or 13, the cartridge tray 30 has a developer support member 301 that supports and guides the insertion and removal of the developing unit 24 along the rotational axis direction of the photosensitive drum 2, and a drum support member 302 that supports and guides the drum unit 23 along the axis direction of the photosensitive drum 2. The developer support member 301 as a developer support portion is provided in a longitudinal shape extending in the rotational axis direction of the photosensitive drum 2 so as to guide and support the developing unit 24 along the rotational axis direction of the photosensitive drum 2. The drum support member 302 is provided in a longitudinal shape extending in the rotational axis direction of the photosensitive drum 2 so as to guide and support the drum unit 23 along the rotational axis direction of the photosensitive drum 2.

[0034] 2, 11, and 12, a portion of the cartridge tray 30 is disposed directly below the developing unit 24. The developing unit support member 301 forms a space 310 (see FIG. 11) between itself and the bottom surface of the developing unit 24, and functions as a duct through which developer-cooling air flows. As will be described later, the opening at one end (front side) of the space 310 formed by the developing unit support member 301 and the bottom surface of the developing unit 24 in the longitudinal direction communicates with an opening 41A of a front duct 41 that draws air from outside the apparatus main body through an opening 1021 of the inner door 102 (see FIG. 16).

[0035] As shown in FIGS. 14 and 15, a developer support member 301, a developer pressure piece (front) 32, a developer pressure piece (rear) 33, and a developer stay link 34 are provided on the cartridge tray 30. The developer pressure piece (front) 32 and the developer pressure piece (rear) 33 are fixed to the developer support member 301 and hold and press the developer unit 24 toward the photosensitive drum 2. A developer stay link 34 engaged with an inner door 102 is fixed to the end of the front side of the developer support member 301. The inner door 102 has a link engagement portion 102B that engages with the developer stay link 34, which is located closer to the end than the rotation shaft 102A. Therefore, as the inner door 102 rotates, the door moves in the direction of rotation along a circular locus whose radius is the distance between the rotation shaft 102A and the link engagement portion 102B.

[0036] That is, as shown in FIG. 15, opening the inner door 102 causes the link engagement portion 102B to also rotate and move toward the rear of the apparatus. This causes the engaged developer stay link 34 to slide toward the rear of the apparatus in the direction of arrow R, and the two developer pressure pieces (32, 33) integrally formed through the developer support member 301, which is a sliding member, also slide in the direction R. This means that, as shown in FIG. 15, the two developer pressure pieces (32, 33) are disengaged from the positions holding the developer unit 24, and the developer unit 24 moves due to its own weight in the direction of arrow D, which is the direction in which it retreats from the photosensitive drum 2. As described above, the developer unit 24 retreats in conjunction with the opening of the inner door 102. Note that when closing the inner door 102, the developer unit 24 is moved toward and pressed against the photosensitive drum 2 by following the reverse procedure of the opening procedure.

[0037] 11 to 13, the cartridge tray 30 has a lifting duct 69 between the developing unit support member 301 that supports the developing unit 24 and the drum support member 302 that supports the drum unit 23, with respect to the rotation direction of the photosensitive drum 2. For convenience of illustration, only a portion of the lifting duct 69 is shown in FIG. 11. The lifting duct 69, which serves as an exposure support portion, detachably supports the exposure unit 4. As shown in FIGS. 12 and 13, the lifting duct 69 has a longitudinal shape that extends in the front-rear direction (the direction of the rotation axis of the photosensitive drum 2) similar to the exposure unit 4 so as to be able to support the entire exposure unit 4. The lifting duct 69 is provided on the cartridge tray 30 between the developing unit support member 301 and the drum support member 302, so as to be movable between an exposure position (see FIG. 2) where the exposure unit 4 exposes the photosensitive drum 2 and a retracted position (see FIG. 3) where the exposure unit 4 is retracted from the exposure position.

[0038] In this embodiment, the lifting duct 69 supports the exposure unit 4, and at the same time forms a flow path between the lifting duct 69 and the exposure unit 4 for air to cool the exposure unit 4. As shown in Figure 11, the lifting duct 69 can direct air from a duct unit 60 (described later) to the mounting board 50 of the exposure unit 4 through an opening 69a between a duct left wall 69L and a duct right wall 69R. In other words, the lifting duct 69 can blow air from the duct unit 60 onto the exposure unit 4 without leaking it toward the adjacent developing unit 24 or drum unit 23.

[0039] <Cooling airflow configuration> Next, the cooling airflow configuration of the developing unit 24 and the exposure unit 4 in this embodiment will be described using Figures 16 to 22, with reference to Figures 2 and 11. In Figure 16, the airflow for cooling the developing unit 24 (referred to as the developing cooling airflow) is shown by a solid line, and the airflow for cooling the exposure unit 4 (referred to as the exposure cooling airflow) is shown by a dotted line.

[0040] As described above, the developing unit 24 contains the transport screw 7, which rotates at high speed, and the toner, which circulates at high speed. The heat generated in the bearing of the transport screw 7 and in the toner causes the temperature of the developing unit 24 to rise. Once image formation is complete, the temperature of the developing unit 24 gradually drops. However, as long as image formation continues, the temperature of the developing unit 24 continues to rise and reach a high temperature as long as the heat capacity of the developing unit 24 allows. Because toner is easily melted by heat, if the temperature of the developing unit 24 rises above a predetermined temperature, the toner may melt within the developing unit 24 and adhere to the developing sleeve 5, resulting in poor coating of the developing sleeve 5 and poor development. To prevent this, the developing unit 24 must be cooled to prevent the temperature of the developing unit 24 from rising above a predetermined temperature.

[0041] As shown in Figure 16, image forming apparatus 100 has intake fan 40 for cooling the developing devices and front duct 41 for sending air from outside the apparatus body to each developing unit 24. Intake fan 40, which serves as a second intake fan, is provided on the right side of the front of image forming apparatus 100, and draws air from outside the apparatus body into the apparatus through intake port 101A provided on the right side of front cover 101. Front duct 41, which serves as a second intake duct, is provided on a second surface (back surface) of front cover 101 opposite to a first surface (front surface) that constitutes part of the exterior of image forming apparatus 100, and extends in the left-right direction, which is the direction in which developing units 24 are arranged.

[0042] The front duct 41 has openings 41A at positions corresponding to each developing unit 24. The openings 41A of the front duct 41 are provided at positions facing the openings 1021 of the inner doors 102 of each cartridge tray 30 in the direction of the rotation axis of the photosensitive drum 2, and are connected to each other by closing the front cover 101. The openings 1021 of each inner door 102 are provided at positions corresponding to openings at one end side in the longitudinal direction of a space 310 (see FIG. 11 ) formed between the developing unit 24 and the developing device support member 301, and are connected to each other by closing the inner door 102. That is, the front duct 41 is connected to the space 310 formed between the developing unit 24 and the cartridge tray 30 (more specifically, the developing device support member 301) through the openings 1021 of the inner door 102. In other words, an open third communication section 36 that connects the front duct 41 and the space 310 is formed on one end side of the developing support member 301 in the longitudinal direction. As a result, the air flow generated by the intake fan 40 passes through the space 310 (second path) between the developing unit 24 and the cartridge tray 30, as shown in FIGS. 16 and 17, and forms a developer cooling air flow that cools the developing unit 24 along at least a part of the developing unit 24.

[0043] In this embodiment, a discharge port 35 (fourth communication portion) is formed near the rear of the bottom of the developing unit support member 301 of the cartridge tray 30. After passing through the space 310 between the developing unit 24 and the cartridge tray 30 and cooling the developing unit 24, the air is discharged from the discharge port 35 to the duct unit 60. This discharge port 35 is connected to an inlet 601 (fifth communication portion) formed on the upper surface of the duct unit 60. Therefore, the air discharged from the discharge port 35 of the developing unit support member 301 flows into the duct unit 60 from the inlet 601. The duct unit 60 is provided with an exhaust fan 63, and the air after cooling the developing unit 24 is exhausted to the outside of the apparatus main body by the exhaust fan 63 together with the air passing through the duct unit 60, i.e., the air after cooling the exposure unit 4.

[0044] On the other hand, the exposure unit 4, which generates heat in accordance with the light emission intensity of the light-emitting element 51, is located close to the development unit 24, which contains heat-sensitive toner. As already mentioned, if the temperature of the development unit 24 rises above a predetermined temperature, the toner may melt inside the development unit 24, causing development defects. To prevent this, the above-mentioned developer cooling air flow is provided to cool the development unit 24. However, to more effectively suppress the temperature rise of the development unit 24, it is preferable to cool the exposure unit 4, which may generate heat that affects the development unit 24. In particular, when the image formation process is repeated frequently, i.e., when productivity is high, or when images with high image density are output continuously, the light-emitting element 51 emits light for a long time and emits a large amount of light, resulting in a large amount of heat generated by the exposure unit 4. Therefore, cooling the exposure unit 4 is likely to be effective.

[0045] To facilitate heat dissipation from the exposure unit 4 and prevent the temperature of the exposure unit 4 from rising, the housing 54 to which the mounting board 50 is fixed in the exposure unit 4 is made of a material that easily dissipates heat, such as a metal that easily dissipates heat. That is, the housing 54 of the exposure unit 4 is used as a heat sink, allowing the exposure unit 4 to easily dissipate heat and preventing heat accumulation, thereby providing a design that is favorable for cooling the exposure unit 4. However, even if the housing 54 is used to dissipate heat from the exposure unit 4, cooling by heat dissipation may not be sufficient, and the heat from the exposure unit 4 may cause the development unit 24 to heat up, resulting in development defects. For this reason, even when a development cooling airflow for cooling the development unit 24 is formed, there is a risk that the development unit 24 may heat up due to the heat from the exposure unit 4, so it is effective to form an exposure cooling airflow for cooling the exposure unit 4.

[0046] However, when forming the exposure cooling airflow, certain considerations must be taken into account. The developing sleeve 5 is positioned in the cartridge tray 30 so that it is close to the exposure unit 4 (see Figures 11 and 12). The surface of the developing sleeve 5 is coated with toner, and due to its structure, scattered toner can adhere near the bearings at both ends and around the developing unit 24. This is because the high-speed rotation of the developing sleeve 5 and the conveying screw 7 increases the internal pressure of the developing unit 24, causing toner to scatter from gaps in the developing unit 24. When forming the exposure cooling airflow, it is necessary to prevent the toner from diffusing inside the main body of the device.

[0047] <Duct unit> Therefore, in this embodiment, an exposure cooling airflow is formed in which air is blown from duct unit 60 onto exposure units 4 along a path different from the path of the development cooling airflow. Duct unit 60 is an exposure cooling unit for cooling exposure units 4 supported by elevator ducts 69 with air drawn in from outside the apparatus body, and is attached to the apparatus body of image forming apparatus 100 directly below cartridge tray 30. As shown in FIG. 18 , duct unit 60 has an intake fan 62 and an intake duct 205 (first intake duct) for cooling exposure devices, which send air from outside the apparatus body to each exposure unit 4, and an exhaust fan 63 and an exhaust duct 206 for exhausting the air to the outside of the apparatus body after cooling each exposure unit 4. Duct unit 60 has an intake port 203 and an exhaust port 204, with intake fan 62 provided in intake port 203 and exhaust fan 63 provided in exhaust port 204.

[0048] In this embodiment, as shown in Fig. 16, duct unit 60 is attached to the apparatus body so that intake fan 62 as a first intake fan is disposed toward the front of image forming apparatus 100 on the left side of image forming apparatus 100, and exhaust fan 63 is disposed toward the rear of image forming apparatus 100. Openings (not shown) with louvers are formed in side cover 106 on the left side of image forming apparatus 100 at positions facing intake fan 62 and exhaust fan 63. These openings formed in side cover 106 communicate with intake port 203 and exhaust port 204, where intake fan 62 and exhaust fan 63 are disposed, respectively. Therefore, air is taken in by intake fan 62 and exhausted by exhaust fan 63 through the openings formed in side cover 106.

[0049] As shown in FIGS. 18 and 19 , duct unit 60 has a communication section 201 (first communication section) formed on its upper surface, near the front of image forming apparatus 100, for each exposure unit 4. Since communication section 201 connects the inside of intake duct 205 with the outside, air outside the apparatus body drawn in through intake port 203 by intake fan 62 is discharged from each communication section 201 through intake duct 205. Also, as shown in FIG. 18 , duct unit 60 has a communication section 202 (second communication section) formed on its upper surface, near the rear of image forming apparatus 100, for each exposure unit 4. Since communication section 202 connects the inside of exhaust duct 206 with the outside, air taken into exhaust duct 206 from communication section 202 by exhaust fan 63 (more specifically, air after cooling exposure unit 4) is discharged to the outside of the apparatus body through exhaust port 204.

[0050] 19, the communication portion 201 of the intake duct 205 communicates with a space 64 (first path) formed by the cartridge tray 30 and the lifting duct 69. When the duct unit 60 is attached to the image forming apparatus 100, the communication portion 201 of the duct unit 60 is pressed against the space 64 formed by the cartridge tray 30 and the lifting duct 69, and the space 64 communicates with the communication portion 201. The space 64 is formed in a position corresponding to the communication portion 201 of the duct unit 60 for each exposure unit 4 in the left-right direction.

[0051] As shown in FIG. 20 , the space 64 is surrounded by the developer support member 301 and drum support member 302 of the cartridge tray 30, a duct left wall 69L and a duct right wall 69R provided in the left-right direction of the lift duct 69, and a duct front wall 69F and a duct rear wall 69B provided in the front-rear direction, and extends in the longitudinal direction (front-rear direction) along at least a portion of the exposure unit 4. The space 64 includes most of the mounting board 50 in the longitudinal direction of the exposure unit 4 and is formed within a cooling range La that can sufficiently cool the exposure unit 4 by blowing air thereto. The exposure unit 4 is cooled by passing air from outside the apparatus main body through this space 64. That is, the space 64 functions as a duct that extends from the duct unit 60 to the exposure unit 4 via the cartridge tray 30 and the lift duct 69.

[0052] As shown in FIG. 19 , an intake fan 62 disposed in the duct unit 60 toward the front of the image forming apparatus 100 draws air from outside the apparatus body into an intake duct 205 through an intake port 203. The air drawn into the apparatus body flows along the intake duct 205 from the left side to the right side of the apparatus, with a portion branching off into communication sections 201 for each color provided on the upper surface of the intake duct 205. The air branched off into communication sections 201 is sent upward through a space 64 formed by the cartridge tray 30 and the lift duct 69, and is blown onto the mounting board 50 of the exposure unit 4 through an opening 69a of the lift duct 69, which communicates vertically, and an opening 55A of the exposure unit 4 (see FIG. 11 ). The air blown onto the mounting board 50 flows within the space 64 along the mounting board 50 from the front to the rear, cooling the mounting board 50 during this process.

[0053] 21 , the exhaust fan 63, which is disposed in the duct unit 60 toward the rear of the image forming apparatus 100, operates simultaneously with the intake fan 62 to exhaust air from the duct unit 60 to the outside of the apparatus body. That is, when the exhaust fan 63 operates, air flowing from the front to the rear along the mounting board 50 in the space 64, as shown in FIG. 22 , is taken into the exhaust duct 206 through the communication sections 202 for each color provided on the upper surface of the exhaust duct 206. The air taken in through the communication sections 202 of the exhaust duct 206 merges sequentially through the communication sections 202 from right to left in the exhaust duct 206, flows from right to left in FIG. 21 , and is exhausted to the outside of the apparatus body through the exhaust port 204. After cooling the mounting board 50 for each color, the air is exhausted to the outside of the apparatus body through the exhaust duct 206.

[0054] In this embodiment, as shown in Fig. 20, an outlet 35 through which air is discharged after cooling the developing unit 24 is formed in the cartridge tray 30 near the rear of the bottom of the developer support member 301, within the cooling range La. On the other hand, as shown in Fig. 18, the duct unit 60 has an inlet 601 that communicates with the outlet 35 of the cartridge tray 30 on the upper surface of the exhaust duct 206, at a position corresponding to the outlet 35. The outlet 35 and the inlet 601 are provided so that the air after cooling the developing unit 24 can be exhausted to the outside of the apparatus main body through the exhaust duct 206 of the duct unit 60, together with the air after cooling the exposure unit 4.

[0055] FIG. 23 shows a cross-sectional view of the confluence of the developer cooling airflow and the exposure cooling airflow in the exhaust duct 206. As shown in FIG. 23, when the exhaust fan 63 operates, air that has cooled the developer units 24 by passing through the space 310 is taken into the exhaust duct 206, merges with the communication sections 202 from right to left in the exhaust duct 206 in FIG. 23, flows from right to left, and is exhausted to the outside of the apparatus body through the exhaust port 204. In this way, the air that has cooled the developer units 24 of each color is exhausted to the outside of the apparatus body through the exhaust duct 206. At this time, the air that has cooled the developer units 24 is merged with the air that has cooled the mounting substrate 50 in the exhaust duct 206, and the air can be efficiently exhausted to the outside of the apparatus body through the exhaust duct 206 using a single exhaust fan 63.

[0056] As described above, in this embodiment, the exposure unit 4 and the developer unit 24 are cooled by different airflows: the exposure-cooling airflow passing through the first path (space 64) and the developer-cooling airflow passing through the second path (space 310). The air after exposure cooling is merged with the air after developer cooling in the exhaust duct 206 of the duct unit 60, and the air after developer cooling is exhausted from the exhaust duct 206 by the exhaust fan 63 together with the air after exposure cooling. That is, in the duct unit 60, which takes in air to cool the exposure unit 4 and forms the exposure-cooling airflow, the exhaust duct 206 for exhausting the air after exposure cooling is also used as a duct for exhausting the air after developer cooling. This eliminates the need to provide separate exhaust ducts for cooling the exposure unit and the developer unit, eliminating the need to secure a large space within the apparatus main body, contributing to the miniaturization of the image forming apparatus 100 without increasing its size. Furthermore, the exhaust fan 63 for exhausting the air after cooling for exposure and cooling for development only needs to be disposed at one location in the exhaust duct 206, which also contributes to space saving.

[0057] Incidentally, if the balance between the total amount of air flowing into the duct unit 60 from the intake fan 62 and the inlet 601 and the total amount of air exhausted from the duct unit 60 by the exhaust fan 63 is disrupted, the developer cooling airflow and the exposure cooling airflow may be disrupted. For example, if the total amount of air inflow is greater than the total amount of air exhausted, air that cannot be exhausted by the exhaust fan 63 may leak through gaps in the duct unit 60. Alternatively, if the total amount of air exhausted is greater than the total amount of air inflow, air may be drawn into the duct unit 60 through gaps in the duct unit 60. If the developer cooling airflow and the exposure cooling airflow are disrupted in this way, toner may scatter, or the developer unit 24 and the exposure unit 4 may not be sufficiently cooled.

[0058] In view of the above, when fans with the same performance and predetermined airflow rates are used for the exhaust fan 63 that exhausts air from the duct unit 60, the intake fan 40 for developer cooling, and the intake fan 62 for exposure cooling, it is preferable to arrange two exhaust fans 63 in series in the duct unit 60, as shown in Fig. 24. In this case, the total exhaust rate of the two exhaust fans 63 arranged in series is approximately the same as the sum of the intake rate of the intake fan 40 for developer cooling and the intake rate of the intake fan 62 for exposure cooling, so that the balance between the total amount of air flowing into the duct unit 60 and the total amount of air discharged from the duct unit 60 by the exhaust fan 63 is not lost. Note that using fans with the same performance for the exhaust fan 63, the intake fan 40, and the intake fan 62 allows the same fans to be used during assembly, improving assembly efficiency and reducing costs.

[0059] Alternatively, if there is not enough space in the duct unit 60 to arrange two exhaust fans 63 in series, a wide reinforced fan with a larger exhaust volume than the development cooling intake fan 40 and the exposure cooling intake fan 62, which have the same performance, may be used as the exhaust fan 63, as shown in Fig. 25. In this case, by using an reinforced fan with an exhaust volume approximately equal to the sum of the intake volume of the intake fan 40 and the intake volume of the exposure cooling intake fan 62, the balance between the total amount of air flowing into the duct unit 60 and the total amount of air discharged from the duct unit 60 by the exhaust fan 63 is not lost.

[0060] Furthermore, as described above, the exposure unit 4 generates a large amount of heat when the image formation process is repeated frequently, i.e., when productivity is high, or when images with high image density are continuously output. Therefore, in order to more efficiently cool the exposure unit 4, it is preferable to use a fan with variable airflow rate as the exposure cooling intake fan 62 and control the intake air volume of the intake fan 62 based on image density and productivity. In this case, it is necessary to control the intake air volume of the developer cooling intake fan 40 and the exhaust air volume of the exhaust fan 63 in accordance with the control of the intake air volume of the exposure cooling intake fan 62 so that the exhaust air volume of the exhaust fan 63 and the sum of the intake air volumes of the developer cooling intake fan 40 and the exposure cooling intake fan 62 are approximately equal. However, because the temperature of the developer unit 24 is generally less likely to rise than that of the exposure unit 4, the developer cooling intake fan 40 is often controlled to a constant intake air volume. Therefore, in this embodiment, the exhaust air volume of the exhaust fan 63 is controlled in accordance with the control of the intake air volume of the exposure cooling intake fan 62. This is explained below.

[0061] <Control unit> As shown in Fig. 2, the image forming apparatus 100 includes a control unit 500. First, the control unit 500 will be described with reference to Fig. 26. Fig. 26 shows a control system related to cooling of the developing unit 24 and the exposure unit 4. That is, in addition to those shown in the figure, various devices such as motors and power supplies for operating the image forming units 1Y to 1K and the intermediate transfer belt unit 8 are connected to the control unit 500, but as this is not the main point of the invention, illustration and description of these devices will be omitted here.

[0062] The control unit 500 performs various controls of the image forming apparatus 100, such as image formation operations, and includes, for example, a central processing unit (CPU) 501 and a memory 502. The memory 502 is configured with a read-only memory (ROM) and a random access memory (RAM). The memory 502 stores various programs and data for controlling the image forming apparatus 100. The CPU 501 can execute the various programs stored in the memory 502 and can operate the image forming apparatus 100 by executing the various programs. The memory 502 can also temporarily store results of arithmetic processing associated with the execution of the various programs. The control unit 500 can perform various settings based on user input from the operation unit 46. The operation unit 46 may be, for example, a touch panel, and accepts inputs to start various programs, such as an "image formation job," and settings of various data in response to user touch operations.

[0063] In addition to the operation unit 46, the control unit 500 is connected to an intake fan 62 for exposure cooling, an intake fan 40 for development cooling, and an exhaust fan 63. When the control unit 500 determines that the development unit 24 and the exposure unit 4 need to be cooled during execution of an image formation job, it operates the intake fan 62 for exposure cooling, the intake fan 40 for development cooling, and the exhaust fan 63. FIG. 27 shows an example of the cooling process of the development unit 24 and the exposure unit 4 executed by the control unit 500. Note that, here, an example will be described in which one fan with the same performance is used for the intake fan 62 for exposure cooling, the intake fan 40 for development cooling, and the exhaust fan 63 (see FIG. 16).

[0064] <Cooling treatment> As shown in FIG. 27, the control unit 500 receives the start of an "image forming job" from the operation unit 46 or an external device (not shown) (S1). At this time, the control unit 500 receives information regarding the exposure of the photosensitive member, such as the image density of the toner image to be formed on the sheet S and the number of sheets of recording material on which the toner image is to be continuously formed. Upon receiving the start of the "image forming job", the control unit 500 controls the intake fan 62 for cooling the exposure unit, the intake fan 40 for cooling the development unit, and the exhaust fan 63 based on the fan control table shown in Table 1 (S2). The fan control table shown in Table 1 is stored in advance in the memory 502.

[0065] The "%" in Table 1 is a control value corresponding to the intake and exhaust volume of each fan. Also, "Image Density" in Table 1 indicates the image density of the toner image formed on sheet S, and "Productivity" in Table 1 indicates the number of sheets of recording material on which a toner image is continuously formed. Furthermore, in Table 1, values ​​higher than a predetermined threshold are indicated as "high," and values ​​below the predetermined threshold are indicated as "low." [Table 1]

[0066] As shown in Table 1, the fan control table defines fan operation modes corresponding to image density and productivity. Here, when the image density is "high" and the productivity is "high," the exposure cooling intake fan 62 is operated at "75%," the developer cooling intake fan 40 is operated at "25%" (a constant value), and the exhaust fan 63 is operated at "100%." ​​If the intake fan 62, the intake fan 40, and the exhaust fan 63 have the same performance, the above control maintains a balance between the total amount of air flowing into the duct unit 60 (25 + 75) and the total amount of air exhausted from the duct unit 60 by the exhaust fan 63 (100). For example, when the image density is "low" and the productivity is "high," the exposure cooling intake fan 62 is operated at "25%,," the developer cooling intake fan 40 is operated at "25%" (a constant value), and the exhaust fan 63 is operated at "50%." Even in this case, the above control maintains a balance between the total amount of air flowing into duct unit 60 (25+25) and the total amount of air exhausted from duct unit 60 by exhaust fan 63 (50). In this way, control unit 500 controls each fan using a fan operation mode that corresponds to image density and productivity based on the fan control table in Table 1. This makes it difficult for the development cooling airflow and exposure cooling airflow to be disrupted, preventing toner scattering and allowing development unit 24 and exposure unit 4 to be sufficiently cooled.

[0067] Although not explained here, the control values ​​of the intake fan 62 for exposure cooling, the intake fan 40 for development cooling, and the exhaust fan 63 may be changed according to the temperature of a temperature sensor that detects the temperature inside the apparatus. [Explanation of symbols]

[0068] 2...photosensitive member (photosensitive drum), 4...exposure section (exposure unit), 24...development section (development unit), 35...fourth communication section (exhaust port), 36...third communication section, 40...second intake fan (intake fan), 41...second intake duct (front duct), 51...light emitting element, 62...first intake fan (intake fan), 63...exhaust fan, 64...first path (space), 69...exposure support section ( Lifting duct), 100... image forming apparatus, 101... opening / closing section (front cover), 201... first communicating section (communicating section), 202... second communicating section (communicating section), 205... first intake duct (intake duct), 206... exhaust duct, 301... developer supporting section (developer supporting member), 310... second path (space), 500... control section, 601... fifth communicating section (inlet), S... recording material (sheet)

Claims

1. a photoreceptor that rotates around a rotation axis along the longitudinal direction; an exposure unit having a plurality of light-emitting elements arranged in the longitudinal direction, and causing the plurality of light-emitting elements to emit light to form a latent image on the charged surface of the photoreceptor; a developing unit that develops the latent image formed on the photosensitive member with a developer; A first intake fan; a first intake duct that guides the air drawn in by the first intake fan along at least a portion of the exposure unit to a first path through which the air drawn in by the first intake fan flows to cool the exposure unit; A second intake fan; a second intake duct that guides the air drawn by the second intake fan along at least a portion of the developing unit to a second path through which the air drawn by the second intake fan flows to cool the developing unit; Exhaust fans and an exhaust duct that merges the air flowing through the first path and the air flowing through the second path and exhausts the merged air by the exhaust fan, An image forming apparatus characterized by:

2. an exposure support part that supports the exposure part, the first path is formed between the exposure unit and the exposure support unit, the first intake duct has a first communication portion that communicates with the first path, the exhaust duct has a second communication portion that communicates with the first path; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

3. a development support unit that supports the development unit, the second path is formed between the developing unit and the developing support unit, the developing support portion is formed with a third communication portion that communicates the second intake duct with the second path, and a fourth communication portion that communicates the exhaust duct with the second path.

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

4. the exhaust duct has a fifth communication portion that communicates with the fourth communication portion.

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

5. an opening / closing unit having a first surface that constitutes a part of the exterior of the image forming apparatus and a second surface opposite to the first surface, the opening / closing unit being provided on the image forming apparatus so as to be able to be opened and closed; The second intake duct is disposed on the second surface of the opening / closing portion.

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

6. A plurality of the photoreceptors; a plurality of exposure sections for forming latent images on the charged surfaces of the plurality of photoreceptors; a plurality of developing units that develop latent images formed on the plurality of photosensitive members, respectively, with a developer; the first intake duct sends the air taken in by the first intake fan to the first paths along which air for cooling each of the exposure units flows in the longitudinal direction; the second intake duct sends the air drawn in from the second intake fan to the second paths along the longitudinal direction through which air for cooling each of the developing units flows; the exhaust duct merges the air flowing through the plurality of first paths and the air flowing through the plurality of second paths, and exhausts the merged air by the exhaust fan.

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

7. an exhaust volume of air exhausted from the exhaust duct by the exhaust fan is substantially equal to a sum of an intake volume of air taken into the first intake duct by the first intake fan and an intake volume of air taken into the second intake duct by the second intake fan; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. the first intake fan and the second intake fan are fans with a predetermined air volume, The exhaust fan is configured by arranging two fans in series, each having the predetermined airflow volume.

8. The image forming apparatus according to claim 7,

9. The exhaust fan is a fan whose air volume is variable, a control unit for controlling the exhaust fan, the control unit controls the air volume of the exhaust fan so that the sum of the intake volume of air drawn into the first intake duct by the first intake fan and the intake volume of air drawn into the second intake duct by the second intake fan is substantially equal to 8. The image forming apparatus according to claim 7,

10. the first intake fan is a fan whose air volume is variable, the control unit acquires information regarding exposure of the photosensitive member by the exposure unit, and changes the air volume of the first intake fan based on the acquired information regarding exposure of the photosensitive member.

10. The image forming apparatus according to claim 9,

11. The information regarding the exposure is the image density of the toner image formed on the recording material.

11. The image forming apparatus according to claim 10.

12. The information regarding the exposure is the number of sheets of recording material on which toner images are continuously formed.

11. The image forming apparatus according to claim 10.

Images