Image forming apparatus

Abstract

To provide an image forming apparatus that can prevent an increase in size of the apparatus and guide outside air taken in by intake fans toward a plurality of units through ducts while ensuring a sufficient amount of blast.SOLUTION: In a left side intake unit 124, an intake fan for development 180a and intake fans for electrification 177a, 177b are disposed in a left side face part of a left side body duct 174. At a right side face part 1742 of the left side body duct 174, intake fans for development 180b, 180c, 180d are disposed. In the left side intake unit 124, outside air taken in from intake ports according to the operation of the intake fans for development 180a-180d and intake fans for electrification 177a, 177b is branched through communication ports 1741a-1741c and communication ports 1742a-1742c and sent to developing devices and electrifying devices. With this configuration, guiding of outside air can be achieved with a simple configuration while a sufficient amount of blast is ensured without an increase in size of the apparatus.SELECTED DRAWING: Figure 7

Description

Technical Field

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

Background Art

[0002] In an image forming apparatus, a toner image is formed on an image carrier such as a photosensitive drum or an intermediate transfer belt, the toner image is transferred from the image carrier to a recording material, and then heat and pressure are applied by a fixing unit to fix the toner image on the recording material. In such an image forming apparatus that forms an image on a recording material using toner, a developing unit that develops an electrostatic latent image on the image carrier using toner is provided. The developing unit houses toner therein and circulates and conveys the toner while stirring it by a conveying screw within the developing unit. Therefore, heat is generated in the developing unit according to the stirring operation of the toner. Thus, a plurality of units that generate heat, such as a fixing unit and a developing unit, are provided inside the image forming apparatus.

[0003] Therefore, a configuration has been proposed in which a plurality of components to be cooled, such as a fixing unit and a developing unit, are cooled by outside air sucked in from an intake port by an intake fan (Patent Document 1). In the apparatus described in Patent Document 1, in order to efficiently blow air to each of the plurality of components to be cooled, a plurality of fans are provided, and ducts connecting the fans from the intake port are provided in the same number as the number of fans. In this case, each of the plurality of components to be cooled can be efficiently cooled.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, an image forming apparatus that forms an image on a recording material using toners of a plurality of colors includes a plurality of image forming units (also called image forming stations) that form toner images of respective colors on a photosensitive drum for each color. When there are a plurality of image forming units, it is necessary to cool each of the cooling targets of each image forming unit. In this case, as in the apparatus described in Patent Document 1, if a plurality of ducts are provided to connect fans from an air inlet for each of the plurality of cooling targets, although a sufficient air volume can be ensured for each cooling target, the area occupied by those ducts inside the image forming apparatus increases. Therefore, conventionally, in order to secure a space for individually arranging a fan and a duct for each of a plurality of units, it has been necessary to increase the size of the apparatus, but this has been difficult to adopt because it runs counter to the recent demand for miniaturization of apparatuses.

[0006] In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of guiding outside air sucked by an intake fan toward a plurality of units via a duct while suppressing an increase in the size of the apparatus and ensuring a sufficient air volume for guiding.

Means for Solving the Problems

[0007] An image forming apparatus according to an embodiment of the present invention is an image forming apparatus that forms an image on a recording material, and includes a first photoreceptor, a second photoreceptor, a first developing unit that supplies toner to the first photoreceptor and forms a toner image, a second developing unit that supplies toner to the second photoreceptor and forms a toner image, a first fan, and a second fan. A main duct having a space formed therein that communicates with an air inlet, and an intake unit having the same. The main duct has a first side surface portion in which a first communication port is formed, and a second side surface portion that faces the first side surface portion and in which a second communication port is formed, The first fan is provided with the first communication to the opening The second fan is the provided with the second communication to the opening The intake unit is configured to be sucked and in response to the operations of the first fan and the second fan and, air and is from the air inlet into the space inside the main duct guided to the first communication port is sent to the first developing unit through, and is sent through the second communication port and the second developing unit to , which is characterized in that.

[0008] An image forming apparatus according to an embodiment of the present invention is an image forming apparatus that forms an image on a recording material, and includes a first photoreceptor, a second photoreceptor, a first charging unit that charges the surface of the first photoreceptor by corona discharge, a second charging unit that charges the surface of the second photoreceptor by corona discharge, a first fan, and a second fan. A main duct having a space formed therein that communicates with an air inlet, and an intake unit having The main duct has a first side surface portion in which a first communication port is formed, and a second side surface portion that faces the first side surface portion and in which a second communication port is formed, The first fan is provided at the first communication to the opening and the second fan is the provided at a second communication to the opening The intake unit is configured to intake air and in response to the operations of the first fan and, air and the second fan from the air inlet into the space inside the main duct and direct the intake air to the first communication port is sent to the first charging unit through, and is sent through the second communication port and the second charging unit to . This is the gist of the present invention.

Advantages of the Invention

[0009] According to the present invention, when guiding outside air intake by an intake fan to a plurality of units via a duct, it is possible to suppress the increase in size of the apparatus and ensure a sufficient air volume for guiding with a simple configuration.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0011] <Image forming system> The schematic configuration of the image forming system including the image forming apparatus of the present embodiment will be described with reference to FIG. 1. The image forming system 1X shown in FIG. 1 includes an image forming apparatus 100 and a finisher apparatus 300. The image forming apparatus 100 and the finisher apparatus 300 are connected so as to be able to transfer a recording material S therebetween. In the present embodiment, the finisher apparatus 300 is a post-process unit that can be attached to the image forming apparatus 100 later for function expansion, and can perform post-processes described later on the recording material S on which a toner image has been fixed by the image forming apparatus 100. The image forming apparatus 100 and the finisher apparatus 300 are connected so as to be able to transmit and receive data to and from each other through a communication interface capable of serial communication or parallel communication.

[0012] <Image forming apparatus> The image forming apparatus 100 is an electrophotographic tandem type full-color printer, and has a first housing 101a and a second housing 101b. In the first housing 101a, various devices such as an image forming unit 700 that realizes processes up to transferring a toner image while conveying the recording material S, and various members are arranged.

[0013] On the other hand, various devices such as a fixing unit 800 and various members that realize the process of conveying the recording material S and fixing the toner image are disposed in the second housing 101b. Further, in the second housing 101b, an operation unit 200 having a display unit capable of displaying various information on the front side and keys capable of inputting various information according to user operations is disposed. Note that an electrical unit (not shown) having a power supply board may be disposed on the back side of the first housing 101a and the second housing 101b. In this specification, when the user operates the operation unit 200 to operate the image forming apparatus 100, the side on which the user stands is referred to as "front", and the opposite side is referred to as "back". Also, the left side surface when viewed from the front is referred to as the "left side surface", and the right side surface when viewed from the front is referred to as the "right side surface".

[0014] The image forming apparatus 100 includes image forming units Pa, Pb, Pc, and Pd that form yellow, magenta, cyan, and black images, respectively. The image forming apparatus 100 forms a toner image on the recording material S according to an image signal read from a document by a document reading apparatus 190 or an image signal received from an external device (not shown) such as a personal computer.

[0015] In the case of this embodiment, an image forming unit 700 that forms a toner image on the recording material S is configured by the image forming units Pa to Pd, primary transfer rollers 24a to 24d, an intermediate transfer belt 130, a plurality of rollers 13 to 15, and a secondary transfer outer roller 11. Examples of the recording material S include papers such as plain paper, thick paper, rough paper, embossed paper, coated paper, plastic films, and cloth.

[0016] As shown in FIG. 1, the image forming units Pa to Pd are arranged side by side along the moving direction of the intermediate transfer belt 130. The intermediate transfer belt 130 is stretched over a plurality of rollers (13, 14, 15) and is moved in the direction of arrow R2. Then, the intermediate transfer belt 130 carries and conveys the toner image that is primarily transferred as described later. A secondary transfer outer roller 11 is arranged at a position facing the secondary transfer inner roller 14 that stretches the intermediate transfer belt 130 with the intermediate transfer belt 130 interposed therebetween, forming a secondary transfer unit T2 that transfers the toner image on the intermediate transfer belt 130 to the recording material S. A fixing unit 800 is arranged downstream of the secondary transfer unit T2 in the recording material conveyance direction.

[0017] On the lower side of the image forming apparatus 100, a plurality (here, two) of cassettes 10 in which the recording material S is accommodated are arranged. These cassettes 10 accommodate recording materials S having different sizes and thicknesses, and the recording material S is selectively conveyed from any of the cassettes 10. The recording material S is conveyed from the cassette 10 through a conveyance path by a conveyance roller 16 toward a registration roller 12. Thereafter, the registration roller 12 rotates in synchronization with the toner image formed on the intermediate transfer belt 130, whereby the recording material S is conveyed toward the secondary transfer unit T2. Note that the recording material S is not limited to that accommodated in the cassette 10, and the recording material S placed on a manual feeding unit (not shown) may be conveyed.

[0018] The image forming units Pa, Pb, Pc, and Pd have substantially the same configuration except that the developing colors of the toner images are different. Therefore, here, the yellow image forming unit Pa will be described as a representative, and the description of the other image forming units Pb, Pc, and Pd will be omitted.

[0019] A cylindrical photosensitive drum 3a is disposed in the image forming unit Pa as a photoreceptor. The photosensitive drum 3a is rotationally driven by a motor (not shown). Around the photosensitive drum 3a, a charging device 2a, an exposure device La, a developing device 1a, a primary transfer roller 24a, and a drum cleaning device 4a are arranged.

[0020] The process of forming, for example, a full-color image by the image forming apparatus 100 will be described. First, when the image forming operation is started, the surface of the rotating photosensitive drum 3a is uniformly charged by the charging device 2a. The charging device 2a is, for example, a corona charger that irradiates charged particles associated with corona discharge to charge the surface of the photosensitive drum 3a to a uniform potential. Next, the photosensitive drum 3a is scanned and exposed by laser light corresponding to the image signal emitted from the exposure device La. Thereby, an electrostatic latent image corresponding to the image signal is formed on the surface of the photosensitive drum 3a. The electrostatic latent image formed on the photosensitive drum 3a is developed into a toner image, which is a visible image, by a developer containing toner and carrier accommodated in the developing device 1a. In other words, the toner image is developed on the photosensitive drum 3a by supplying toner by the developing device 1a. In the developing devices 1a to 1d, the developer is circulated and conveyed while being agitated by a conveying screw (not shown).

[0021] The toner image formed on the photosensitive drum 3a is primarily transferred to the intermediate transfer belt 130 at the primary transfer portion T1 formed between the photosensitive drum 3a and the primary transfer roller 24a disposed with the intermediate transfer belt 130 interposed therebetween. At this time, a primary transfer voltage is applied to the primary transfer roller 24a. The toner remaining on the surface of the photosensitive drum 3a after the primary transfer is removed by the drum cleaning device 4a.

[0022] Such operations are sequentially performed in the respective image forming portions Pa to Pd for yellow, magenta, cyan, and black, and the four-color toner images are superimposed on the intermediate transfer belt 130. Thereafter, the recording material S accommodated in the cassette 10 is conveyed to the secondary transfer portion T2 in accordance with the timing of forming the toner image. Then, by applying a secondary transfer voltage to the secondary transfer outer roller 11, the full-color toner image formed on the intermediate transfer belt 130 is collectively secondarily transferred to the recording material S. The toner remaining on the intermediate transfer belt 130 after the secondary transfer is removed by a belt cleaning device (not shown).

[0023] In the present embodiment, the photosensitive drum 3a corresponds to the first photoreceptor, and the photosensitive drums 3b, 3c, and 3d correspond to the second photoreceptor. Also, the developing device 1a corresponds to the first developing unit, and the developing devices 1b, 1c, and 1d correspond to the second developing unit.

[0024] The recording material S onto which the toner image has been transferred is conveyed to the fixing unit 800. The fixing unit 800 fixes the toner image on the recording material S by applying heat and pressure to the recording material S onto which the toner image has been transferred. In the case of the present embodiment, after heat and pressure are applied to the recording material S by the first fixing device 81, heat and pressure can be selectively applied further by the second fixing device 91. The fixing unit 800 switches whether to convey the recording material S toward the second fixing device 91 after passing through the first fixing device 81 or to avoid the second fixing device 91 and convey it by means of a fixing switching flapper 95.

[0025] The second fixing device 91 is disposed on the downstream side in the conveyance direction of the recording material S from the first fixing device 81. The second fixing device 91 is selectively used for purposes such as further imparting gloss to the toner image on the recording material S fixed by the first fixing device 81. For example, when the recording material S is coated paper such as glossy paper or synthetic paper, the recording material S that has passed through the first fixing device 81 is conveyed through a fixing route 30a so that fixing is performed by both the first fixing device 81 and the second fixing device 91. On the other hand, when the recording material S is uncoated paper such as plain paper, the recording material S that has passed through the first fixing device 81 is conveyed through a fixing bypass route 30b that avoids the second fixing device 91 so that fixing is performed by the first fixing device 81 but not by the second fixing device 91.

[0026] Since the above-described first fixing device 81 and second fixing device 91 may have the same configuration, the first fixing device 81 will be described here as an example. The first fixing device 81 includes a fixing roller 82 (or a fixing belt) that is rotatable in contact with the surface of the recording material S on which the toner image is fixed, and a pressure belt 83 (or a pressure roller) that is press-contacted to the fixing roller 82 to form a fixing nip portion. At least one of the fixing roller 82 and the pressure belt 83 is heated by a heater (not shown). The first fixing device 81 applies heat and pressure to the recording material S when sandwiching and conveying the recording material S on which the toner image is formed in the fixing nip portion formed by the fixing roller 82 and the pressure belt 83, thereby fixing the toner image to the recording material S.

[0027] In the case of this embodiment, the image forming apparatus 100 is capable of duplex printing. In the case of single-sided printing, the recording material S on which the toner image is fixed is conveyed to the discharge conveyance path 150 and discharged to the outside of the image forming apparatus 100. In the case of duplex printing, the recording material S on which the toner image is fixed is conveyed to the duplex reverse conveyance path 600. The duplex reverse conveyance path 600 is formed across the first housing 101a and the second housing 101b. In the duplex reverse conveyance path 600, the recording material S is reversed by a switchback operation, and the front and back surfaces of the recording material S are interchanged. The reversed recording material S is conveyed toward the registration roller 12, and is conveyed to the secondary transfer portion T2 in a state where the non-printed back surface side is directed toward the intermediate transfer belt 130 by the registration roller 12. In the secondary transfer portion T2, the full-color toner image formed on the intermediate transfer belt 130 is collectively secondarily transferred to the recording material S (back surface side). Thereafter, the recording material S is fixed with the toner image by the fixing unit 800 and discharged to the outside of the image forming apparatus 100 with the immediately previously image-formed surface (image forming surface) facing upward. Note that the switching between the above-described discharge conveyance path 150 and the duplex reverse conveyance path 600 is performed by the conveyance switching flapper 160. In this embodiment, the fixing unit 800 is configured to include two fixing devices, but may be configured to include only one fixing device. Further, a configuration may be adopted in which the second housing 101b is provided with a cooling device for cooling the recording material S on which the toner image is fixed by the fixing unit 800.

[0028] A finisher device 300 is connected to the image forming apparatus 100 so as to be able to transfer the recording material S, and the recording material S discharged from the image forming apparatus 100 is conveyed to the finisher device 300. The recording material S conveyed to the finisher device 300 is subjected to post-processes such as a punching process of making holes in the recording material S by the finisher device 300, or a stapling process of bundling a plurality of recording materials S and closing them with a staple. In the finisher device 300, the punched recording material S is discharged separately to the upper discharge tray 301, and the bundle of the stapled recording materials S is discharged to the lower discharge tray 302.

[0029] Hereinafter, the air flow configuration of the outside air in the image forming apparatus 100 will be described with reference to FIGS. 2 to 9 while referring to FIG. 1. FIG. 2 is a left perspective view showing the image forming apparatus 100 with the front door open. FIG. 3(a) is a left perspective view showing the state where the front door of the image forming apparatus 100 is closed, and FIG. 3(b) is a right perspective view showing the state where the front door of the image forming apparatus 100 is closed.

[0030] As shown in FIG. 2, on the front surface of the first housing 101a, a left front door 170a and a right front door 170b as exterior covers are provided so as to be openable and closable in a double-leaf manner as shown in the figure. Further, on the front surface of the first housing 101a, an inner cover 173 is provided inside the left front door 170a and the right front door 170b. The inner cover 173 is for preventing the user from accidentally touching the movable parts and electrical wiring inside the first housing 101a when opening the front doors (170a, 170b). However, the inner cover 173 is detachably provided on the first housing 101a by screws or the like so that a service technician can perform maintenance work. An opening through which the image forming units Pa to Pd (shown by dotted lines) can be individually inserted and removed with respect to the first housing 101a is formed in the inner cover 173, and an inner cover unit 125 is detachably provided on the inner cover 173 so as to cover the image forming units Pa to Pd.

[0031] As shown in FIGS. 2 and 3(a), an intake cover 171 is provided above the left front door 170a, and an intake port 171a is formed in the intake cover 171. And on the left side surface of the first housing 101a, a left intake unit 124 having a fan (see FIGS. 4(a) and 4(b) described later) for sucking outside air from the intake port 171a is provided. In the case of this embodiment, the outside air sucked from the intake port 171a is guided to the image forming units Pa to Pd and the charging devices 2a and 2b via the left intake unit 124 and the inner cover unit 125.

[0032] Also, as shown in FIG. 3(b), a right cover 172 is provided on the right side surface of the first housing 101a, and an intake port 172a is formed in the right cover 172. And on the right side surface of the first housing 101a, a right intake unit 126 having a fan (see FIG. 4(b) described later) for sucking outside air is provided, and sucks outside air from the intake port 172a according to the operation of the fan. In the case of this embodiment, the outside air sucked from the intake port 172a is guided to the charging devices 2c and 2d via the right intake unit 126 and the inner cover unit 125.

[0033] In the charging devices 2a to 2d, the surfaces of the photosensitive drums 3a to 3d are charged by ionizing air by corona discharge to generate ions. Also, the charging devices 2a to 2d generate not only ions but also ozone during corona discharge. However, since ozone easily corrodes, for example, a stainless steel grid (not shown) provided in the charging devices 2a to 2d, it is necessary to recover it. Therefore, in order to send ozone to an ozone recovery filter (not shown) by outside air for recovery, although not shown in the figure, a primary intake duct for blowing outside air to the charging devices 2a to 2d and a primary exhaust duct for exhausting air to the outside of the image forming apparatus 100 via the ozone recovery filter are disposed in the vicinity of the charging devices 2a to 2d.

[0034] <Left intake unit> The left intake unit 124 will be described with reference to FIGS. 4(a) to 7 while referring to FIG. 1. However, for easier understanding of the description, in FIGS. 4(a) and 4(b), the air flow configurations of the developing devices 1a to 1d and the air flow configurations of the charging devices 2a to 2d are separately illustrated.

[0035] As shown in FIGS. 4(a) and 4(b), the left intake unit 124 includes a left main body duct 174, developing intake fans 180a, 180b, 180c, 180d, charging intake fans 177a, 177b, and side ducts 174a, 174b which will be described later. The developing intake fans 180a to 180d are sirocco fans for cooling the developing devices 1a to 1d supported by the first housing 101a. The charging intake fans 177a, 177b are sirocco fans for sending outside air to the charging devices 2a, 2b supported by the first housing 101a. The left main body duct 174 is a duct having a space formed inside that communicates with the above-mentioned intake port 171a.

[0036] As shown in FIGS. 5(a) and 5(b), on the right side surface portion 1742 of the left main body duct 174 as an intake duct, the developing intake fans 180b, 180c, 180d as second fans and the side duct 174b are arranged. That is, on the right side surface portion 1742 as the second side surface portion, communication ports that communicate with the developing intake fans 180b, 180c, 180d are formed, and the outside air sucked from the intake port 171a according to the operation of the developing intake fans 180b, 180c, 180d passes through the inside of the left main body duct 174. Inside the side duct 174b, developing ducts (181b, 181c, 181d) as second ducts are formed. The side duct 174b and the developing intake fans 180b, 180c, 180d are connected so that the outside air that has passed through the developing intake fans 180b, 180c, 180d branches off and passes through the respective developing ducts (181b, 181c, 181d).

[0037] On the other hand, as shown in FIGS. 6(a) and 6(b), on the left side surface 1741 of the left main body duct 174 that faces the right side surface 1742 with a gap therebetween, a developing intake fan 180a, charging intake fans 177a and 177b, and a side duct 174a are arranged. That is, on the left side surface 1741 as the first side surface, a communication port that communicates with the developing intake fan 180a as the first fan and the charging intake fans 177a and 177b is formed, and outside air sucked from the intake port 171a according to the operations of the developing intake fan 180a, the charging intake fans 177a and 177b passes through the inside of the left main body duct 174. In the side duct 174a, a developing duct 181a as the first duct and charging ducts 178a and 178b are formed inside. The side duct 174a is connected to the developing intake fan 180a, the charging intake fans 177a and 177b so that the outside air that has passed through the developing intake fan 180a, the charging intake fans 177a and 177b branches and passes through each duct (181a, 178a, 178b).

[0038] Then, as shown in FIG. 4(a), the outside air sucked from the intake port 171a is sent to the developing devices 1a to 1d via the left main body duct 174, the developing intake fans 180a to 180d, the developing ducts 181a to 181d, and the inner cover unit 125. Also, as shown in FIG. 4(b), the outside air sucked from the intake port 171a is sent to the charging devices 2a and 2b via the left main body duct 174, the charging intake fans 177a and 177b, the charging ducts 178a and 178b, and the inner cover unit 125. In addition, in order to remove dust and the like from the outside air sucked from the intake port 171a, it is preferable to arrange a filter (not shown) in the flow path from the intake port 171a to the left main body duct 174.

[0039] In this embodiment, on the left side surface 1741 and the right side surface 1742 of the left main body duct 174, the intake side is directed toward the left main body duct 174, and the developing intake fans 180a to 180d, which are sirocco fans, and the charging intake fans 177a and 177b are arranged. As described above, in the left main body duct 174, the developing intake fans 180a and the charging intake fans 177a and 177b are arranged on the left side surface 1741, and the developing intake fans 180b, 180c, and 180d are arranged on the right side surface 1742. In this way, by using the common duct from the intake port 171a to the developing intake fans 180a to 180d and the charging intake fans 177a and 177b, the area occupied by the duct can be made smaller than the configuration in which the number of ducts connecting the fans and the intake port is provided according to the number of a plurality of fans, and the enlargement of the image forming apparatus itself due to the enlargement of the duct can be suppressed. In addition, since the arrangement of the ducts can be simplified, the degree of freedom in design can be improved without affecting the arrangement of other units.

[0040] When arranging the developing intake fans 180a to 180d and the charging intake fans 177a and 177b in the left main body duct 174, the inventors examined, by airflow simulation, the arrangement positions where each intake fan is hardly affected by the intake of other intake fans. FIG. 7 shows the arrangement positions of the developing intake fans 180a to 180d and the charging intake fans 177a and 177b in the left intake unit 124.

[0041] As shown in FIG. 7, the developing intake fans 180a to 180d and the charging intake fans 177a and 177b are arranged at positions that do not overlap in the intake direction. To do so, in the left main body duct 174, the communication ports 1741a to 1741c (first communication ports) and the communication ports 1742a to 1742c (second communication ports) are formed so as not to overlap each other when viewed from the right side surface 1742 side (second side surface side) to the left side surface 1741 side (first side surface side) in the passing direction of the outside air passing through the developing intake fan 180a (first fan) (the direction of the rotation axis of the fan).

[0042] In this way, by arranging the communication ports 1741a to 1741c and 1742a to 1742c in the left main body duct 174 at positions not facing each other, it is possible to suppress the occurrence of uneven flow in the left main body duct 174. Further, in the present embodiment, the distance between the left side surface 1741 and the right side surface 1742 of the left main body duct 174 is set to be 20 mm or more and 50 mm or less. By setting the distance between the left side surface 1741 and the right side surface 1742 to be 20 mm or more in this way, it is possible to suppress the occurrence of uneven flow in the air flow generated inside the left main body duct 174 when intake air is drawn from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c.

[0043] For example, if the distance between the left side surface 1741 and the right side surface 1742 is assumed to be less than 20 mm, the air flow generated by the intake by the developing intake fans 180a to 180d and the charging intake fans 177a and 177b hits the left side surface 1741 or the right side surface 1742, resulting in uneven flow. When uneven flow occurs in the air flow, the loss of the air volume when the air flowing into the left main body duct 174 from the intake port 171a is discharged from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c becomes large.

[0044] Therefore, in the present embodiment, by setting the distance between the left side surface 1741 and the right side surface 1742 of the left main body duct 174 to be 20 mm or more, the occurrence of uneven flow inside the left main body duct 174 is suppressed. As a result, the loss when the air flowing into the left main body duct 174 from the intake port 171a is discharged from the communication ports 1741a to 1741c and the communication ports 1742a to 1742c can be suppressed. Therefore, it is possible to ensure a sufficient air volume for a plurality of units.

[0045] Also, if the distance between the left side surface 1741 and the right side surface 1742 is wider than 50 mm, it becomes difficult for uneven flow to occur in the left main duct 174. However, the outer shape of the left main duct 174 becomes larger, and there is a risk that the size of the image forming apparatus itself will increase in order to accommodate a duct with a large outer shape. Therefore, in the present embodiment, the distance between the left side surface 1741 and the right side surface 1742 is set to 40 mm in consideration of the influence of the intake air of each intake fan. In this case, uneven flow does not occur in the left main duct 174, and an increase in pressure loss can be suppressed.

[0046] <Right intake unit> Next, the right intake unit 126 will be described with reference to FIGS. 4(b), 8(a), and 8(b). As shown in FIG. 4(b), the right intake unit 126 includes a right main duct 176, charging intake fans 177c and 177d, and a passage duct 179 described later. The charging intake fans 177c and 177d are fans for blowing outside air to the charging devices 2c and 2d supported by the first housing 101a. The right main duct 176 is a duct in which a space communicating with the above-described intake port 172a (see FIG. 3(b)) is formed inside. In order to remove dust and the like from the outside air taken in from the intake port 172a, it is preferable to arrange a filter (not shown) in the flow path from the intake port 172a to the right main duct 176.

[0047] As shown in FIG. 8(a), the right main duct 176 is provided with charging intake fans 177c and 177d for blowing outside air to the charging devices 2c and 2d. That is, communication ports communicating with the charging intake fans 177c and 177d are formed in the right main duct 176, and the outside air taken in from the intake port 172a passes through the inside of the right main duct 176 according to the operation of the charging intake fans 177c and 177d. Then, as shown in FIG. 8(b), charging ducts 178c and 178d are formed inside the passage duct 179. The passage duct 179 is connected to the charging intake fans 177c and 177d so that the outside air that has passed through the charging intake fans 177c and 177d passes through the charging ducts 178c and 178d.

[0048] Then, as shown in FIG. 4(b), the outside air sucked in from the intake port 172a is sent to the charging devices 2c and 2d via the right main body duct 176, the charging intake fans 177c and 177d, the charging ducts 178c and 178d, and the inner cover unit 125. On the other hand, for the charging devices 2a and 2b, as described above, the outside air sucked in from the intake port 171a (see FIG. 3(b)) is sent via the left main body duct 174, the charging intake fans 177a and 177b, and the inner cover unit 125. Thus, in this embodiment, the left intake unit 124 and the right intake unit 126 are used to blow the outside air to the charging devices 2a to 2d.

[0049] Note that the air flow configurations of the developing devices 1a to 1d and the air flow configurations of the charging devices 2a to 2d are not limited to the above-described configurations. For example, the developing intake fans 180a to 180d may be arranged on the right side surface portion 1742 of the left intake unit 124, and the charging intake fans 177a and 177b may be arranged on the left side surface portion 1741. That is, the number of intake fans arranged on the left side surface portion 1741 and the right side surface portion 1742 of the left intake unit 124 does not have to be the same.

[0050] Also, for example, one charging intake fan 177a and two developing intake fans 180a and 180b may be arranged on the left side surface portion 1741, and three charging intake fans 177b, 177c, and 177d may be arranged on the right side surface portion 1742. In this case, the developing intake fans 180c and 180d are arranged in the right intake unit 126. In this case, the charging device 2a corresponds to the first charging unit, and the charging devices 2b, 2c, and 2d correspond to the second charging unit.

[0051] <Inner cover unit> The inner cover unit 125 will be described with reference to FIG. 9. FIG. 9 is a schematic view showing the inner surface side of the inner cover unit 125. In the present embodiment, as shown in FIG. 9, flexible tubes 183a, 183b, 183c, and 183d as the first relay ducts, which allow outside air for cooling the developing devices 1a to 1d to pass through, are arranged on the inner surface side of the inner cover unit 125. Further, flexible tubes 222a, 222b, 222c, and 222d, which are relay ducts for allowing outside air for blowing air to the charging devices 2a to 2d to pass through, are arranged on the inner surface side of the inner cover unit 125. These flexible tubes 183a to 183d, 222a to 222d are attached to the inner surface of the inner cover unit 125 using, for example, wire saddles.

[0052] The flexible tubes 183a to 183d, 222a to 222d are tubular members having a hollow interior formed of a resin such as PA6 (polyamide) or metal, and are bellows-shaped tubular members in which a large number of convex portions are continuously formed at predetermined intervals on the outer peripheral surface, and are freely bendable. When these flexible tubes 183a to 183d, 222a to 222d are bent, the bending is restricted by the convex portions on the inner side (compression side) of the bend, making it difficult to be bent. Therefore, even when the flexible tubes 183a to 183d, 222a to 222d are bent, the cross-sectional area is maintained compared to before bending, and the outside air can be guided without changing the air volume per unit time.

[0053] With the operation of the intake fans 180a to 180d for development, the outside air sucked in from the intake port 171a flows through the left main body duct 174, the development ducts 181a to 181d, and the flexible tubes 183a to 183d and flows toward the developing devices 1a to 1d. Also, with the operation of the charging intake fans 177a and 177b, the outside air sucked in from the intake port 171a flows through the left main body duct 174, the charging ducts 178a and 178b, and the flexible tubes 222a and 222b and flows toward the charging devices 2a and 2b. Further, with the operation of the charging intake fans 177c and 177d, the outside air sucked in from the intake port 172a flows through the right main body duct 176, the charging ducts 178c and 178d, and the flexible tubes 222c and 222d and flows toward the charging devices 2c and 2d.

[0054] In the present embodiment, on the inner surface side of the inner cover unit 125, for example, the flexible tubes 183a to 183d can be appropriately curved and stretched in a gap avoiding the flexible tubes 222a to 222d that guide the outside air to the charging devices 2a to 2d. That is, by using the flexible tubes 183a to 183d and 222a to 222d, the degree of freedom in duct arrangement within a limited space is increased. Note that the handling of the flexible tubes 183a to 183d and 222a to 222d shown here is an example and is not limited thereto.

[0055] As described above, in the present embodiment, in the left intake unit 124, the developing intake fan 180a and the charging intake fans 177a and 177b are arranged on the left side surface of the left main body duct 174. On the other hand, the developing intake fans 180b, 180c, and 180d are arranged on the right side surface 1742 of the left main body duct 174. In the left intake unit 124, outside air sucked from the intake port 171a according to the operations of the developing intake fans 180a to 180d and the charging intake fans 177a and 177b branches into the communication ports 1741a to 1741c and the communication ports 1742a to 1742c and is blown to the developing devices 1a to 1d and the charging devices 2a and 2b. Thereby, when guiding the outside air sucked by the intake fan toward a plurality of units via the duct, it is possible to realize, with a simple configuration, suppressing the increase in the size of the apparatus and ensuring a sufficient air volume for guiding.

[0056] <Other Embodiments> Note that, in the above-described embodiment, the case where a sirocco fan is used as the intake fan has been described as an example, but the present invention is not limited to this. An axial flow fan may be used as the intake fan. In the left main body duct 174, the case where axial flow fans are used instead of the above-described sirocco fans for the developing intake fans 180b, 180c, 180d and the charging intake fans 177a, 177b is shown in FIGS. 10(a) and 10(b).

[0057] As shown in FIGS. 10(a) and 10(b), when axial fans are used for the developing intake fans 180a to 180d and the charging intake fans 177a and 177b, side ducts 201a to 201f are provided individually for each of them. Here, side duct 201e is provided for the developing intake fan 180a, side duct 201a is provided for the developing intake fan 180b, side duct 201b is provided for the developing intake fan 180c, and side duct 201c is provided for the developing intake fan 180d. Also, side duct 201d is provided for the charging intake fan 177a, and side duct 201f is provided for the charging intake fan 177b. These side ducts 201a to 201f are provided so as to cover the exhaust sides of the developing intake fans 180a to 180d and the charging intake fans 177a and 177b as shown in the figure. Note that since other configurations in the case of using an axial fan are the same as those in the case of using the above-described sirocco fan, the description thereof is omitted here.

[0058] In the above-described embodiment, the case of blowing outside air to the developing devices 1a to 1d and the charging devices 2a to 2d has been described as an example, but it is not limited thereto. For example, the above-described embodiment may also be applied to the case of cooling a conveying member that conveys the recording material S after passing through the first fixing device 81 and the second fixing device 91 (see FIG. 1) with outside air.

[0059] In the above-described embodiment, the electrophotographic image forming apparatus 100 has been described as an example, but it is not limited thereto. For example, the above-described embodiments may also be applied to heat drying type image forming apparatuses such as an inkjet printer and a sublimation printer.

Explanation of Reference Numerals

[0060] 1a…First developing unit (developing device), 1b (1c, 1d)…Second developing unit (developing device), 2a (2b, 2c, 2d)…First charging unit (second charging unit, charging device), 3a…First photoreceptor (photosensitive drum), 3b (3c, 3d)…Second photoreceptor (photosensitive drum), 100…Image forming apparatus, 101a…Housing (first housing), 124…Intake unit (left intake unit), 125…Inner cover unit, 170a, 170b…Exterior cover (left front door, right front door), 174…Intake duct (left main body duct), 180a…First fan (developing intake fan), 180b (180c, 180d)…Second fan (developing intake fan), 181a…First duct (developing duct), 181b (181c, 181d)…Second duct (developing duct), 183a…First relay duct (flexible tube), 183b (183c, 183d)…Second relay duct (flexible tube), 1741…First side surface portion (left side surface portion), 1741a (1741b, 1741c)…First communication port (communication port), 1742…Second side surface portion (right side surface portion), 1742a (1742b, 1742c)…Second communication port (communication port), S…Recording material

Claims

1. An image forming apparatus for forming an image on a recording material, comprising: a first photoreceptor; a second photoreceptor; a first developing unit that supplies toner to the first photoreceptor to form a toner image; a second developing unit that supplies toner to the second photoreceptor to form a toner image; an intake unit having a first fan, a second fan, and a main body duct in which a space communicating with an intake port is formed inside; the main body duct has a first side surface portion in which a first communication port is formed, and a second side surface portion facing the first side surface portion and in which a second communication port is formed; the first fan is provided at the first communication port; the second fan is provided at the second communication port; the intake unit sends the air sucked from the intake port into the space inside the main body duct to the first developing unit through the first communication port and to the second developing unit through the second communication port according to the operations of the first fan and the second fan; An image forming apparatus characterized by the above.

2. The first communication port and the second communication port are formed so as not to overlap each other when viewed along the facing direction in which the first side surface portion and the second side surface portion face each other. The image forming apparatus according to claim 1, characterized by the above.

3. Further comprising a side duct that forms a flow path between the first communication port and the first developing unit. The image forming apparatus according to claim 1 or 2, characterized by the above.

4. A plurality of communication ports are formed as the first communication port on the first side surface portion. The side duct forms a plurality of flow paths corresponding to the plurality of communication ports. The image forming apparatus according to claim 3, characterized by the above.

5. Further comprising a charging unit for charging the first photoreceptor. The intake unit further has a third fan. A third communication port is further formed on the first side surface portion in which the first communication port is formed. The third fan is provided at the third communication port. The side duct forms a first flow path leading from the first communication port to the first developing unit; and a second flow path leading from the third communication port to the charging unit. The image forming apparatus according to claim 3 or 4, characterized by the above.

6. The distance between the first side surface portion and the second side surface portion is 20 mm or more and 50 mm or less. The image forming apparatus according to any one of claims 1 to 5, characterized by the above.

7. The first fan is a sirocco fan or an axial flow fan. The second fan is a sirocco fan or an axial flow fan. The image forming apparatus according to any one of claims 1 to 6, characterized in that.

8. A housing that supports the first developing unit and the second developing unit, An exterior cover that is provided on the front surface of the housing so as to be openable and closable, The housing includes an inner cover unit disposed to face the inner surface of the exterior cover in a closed state. The intake unit has a first duct that passes outside air that has passed through the first communication port, and a second duct that passes outside air that has passed through the second communication port. The inner cover unit has a first relay duct that is connected to the first duct and guides the outside air that has passed through the first communication port toward the first developing unit, and a second relay duct that is connected to the second duct and guides the outside air that has passed through the second communication port toward the second developing unit. The image forming apparatus according to any one of claims 1 to 7, characterized in that.

9. An image forming apparatus that forms an image on a recording material, A first photoreceptor, A second photoreceptor, A first charging unit that charges the surface of the first photoreceptor by corona discharge, A second charging unit that charges the surface of the second photoreceptor by corona discharge, An intake unit having a first fan, a second fan, and a main body duct in which a space communicating with an intake port is formed inside. The main body duct has a first side surface on which a first communication port is formed, and a second side surface that faces the first side surface and on which a second communication port is formed. The first fan is provided at the first communication port, The second fan is provided at the second communication port, The intake unit sends the air sucked from the intake port into the space inside the main body duct to the first charging unit through the first communication port and to the second charging unit through the second communication port according to the operations of the first fan and the second fan. The image forming apparatus, characterized in that.

10. The first communication port and the second communication port are formed so as not to overlap each other when viewed along the opposing direction in which the first side surface and the second side surface oppose each other. The image forming apparatus according to claim 9, characterized in that.

11. The image forming apparatus according to claim 9 or 10, further comprising a side duct that forms a flow path between the first communication port and the first charging unit. Characterized in that.

12. A plurality of communication ports are formed as the first communication ports on the first side surface portion. The side duct forms a plurality of flow paths corresponding to the plurality of communication ports. The image forming apparatus according to claim 11, characterized in that.

13. The image forming apparatus further includes a developing unit that supplies toner to the first photoreceptor and forms a toner image. The intake unit further has a third fan. A third communication port is further formed on the first side surface portion where the first communication port is formed. The third fan is provided at the third communication port. The side duct forms a first flow path leading from the first communication port to the first charging unit, and a second flow path leading from the third communication port to the developing unit. The image forming apparatus according to claim 11 or 12, characterized in that.

14. The distance between the first side surface portion and the second side surface portion is 20 mm or more and 50 mm or less. The image forming apparatus according to any one of claims 9 to 13, characterized in that.

15. The first fan is a sirocco fan or an axial flow fan. The second fan is a sirocco fan or an axial flow fan. The image forming apparatus according to any one of claims 9 to 14, characterized in that.

16. A housing that supports the first charging unit and the second charging unit, an exterior cover provided on the front surface of the housing so as to be openable and closable, and an inner cover unit disposed on the housing so as to face the inner surface of the closed exterior cover. The intake unit has a first duct that passes outside air that has passed through the first communication port, and a second duct that passes outside air that has passed through the second communication port. The inner cover unit has a first relay duct connected to the first duct and guiding the outside air that has passed through the first communication port toward the first charging unit, and a second relay duct connected to the second duct and guiding the outside air that has passed through the second communication port toward the second charging unit. The image forming apparatus according to any one of claims 9 to 15, characterized in that.

Images