Image forming apparatus

Abstract

To provide an image forming apparatus that reduces dust entering a housing.SOLUTION: An image forming apparatus is provided with intake ports 175 for taking in outside air to an opposing part of a top face cover 171 facing front doors 170 of a housing 101. Providing the intake ports 175 in a lower part of the housing near an installation surface 1Z may result in sucking up dust accumulated on the installation surface 1Z. The intake ports 175 can thus be provided in positions above the front doors 170 sufficiently separated from the installation surface 1Z to reduce dust included in the outside air flowing into a main body.SELECTED DRAWING: Figure 2

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 peripheral.

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 device to fix the toner image onto the recording material. The image forming apparatus includes a developing device that forms a toner image on a photosensitive drum charged by a charger. The developing device circulates and conveys toner while stirring it by a conveyance screw inside the developing device, and heat is generated according to this 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. [[ID=1X]]

[0003] Conventionally, a configuration has been proposed in which an air intake is provided in a gap between a door disposed on the front surface of an image forming apparatus main body and an installation surface of the image forming apparatus main body, outside air is taken into the apparatus interior from a duct built in the door, and internal units are cooled (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, if an air intake is provided between the door and the installation surface, it becomes easy to suck dust and the like deposited on the installation surface into the main body. Therefore, foreign substances such as dust may remain inside the main body, and there is a risk of causing image defects due to dust being mixed into the formed image.

[0006] Therefore, the present invention aims to reduce the amount of dust contained in the air drawn in from the air intake port. [Means for solving the problem]

[0007] The image forming apparatus according to the present invention is an image forming apparatus for forming an image on a recording material, and is characterized by comprising: an image forming section having a photoreceptor, a charging unit for charging the photoreceptor by corona discharge, and a developing unit for developing the electrostatic latent image formed on the photoreceptor using toner; a first cover constituting at least a part of the exterior on the front side of the image forming apparatus; a second cover provided above the first cover in the vertical direction and having an opposing portion facing the upper surface portion of the first cover; an air intake port provided on the opposing portion of the second cover; and a fan for drawing in air to be supplied to the image forming section through the air intake port from the gap between the opposing portion and the upper surface portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to reduce the amount of dust contained in the outside air that flows into the main body from the air intake. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing an image forming system equipped with the image forming apparatus of this embodiment. [Figure 2] Left-side perspective view of the image forming apparatus with the front door open. [Figure 3] A left-side perspective view of an image forming apparatus showing the cooling airflow of the developing unit with the front door closed. [Figure 4] A schematic diagram illustrating the airflow configuration for cooling the developing apparatus of the first embodiment. [Figure 5] (a) Right side view showing the left intake unit, (b) Left side view showing the left intake unit. [Figure 6] (a) Front cross-sectional view illustrating the airflow configuration of the developing apparatus, (b) Side cross-sectional view illustrating the airflow configuration of the developing apparatus. [Figure 7] This diagram illustrates the airflow configuration for collecting scattered toner in a developing device, showing (a) a cross-sectional view and (b) a plan view. [Figure 8] (a) Bottom view of the top cover to illustrate the configuration of the air intake, (b) Bottom view of the top cover (holder not shown) to illustrate the configuration of the air intake. [Figure 9] Front view of an image forming apparatus to illustrate the configuration of the air intake. [Figure 10] A schematic diagram illustrating the airflow in the charging device of the second embodiment. [Figure 11] A schematic diagram illustrating the intake airflow configuration in a charging device. [Figure 12] This diagram illustrates the exhaust airflow configuration in a charging device, with (a) a cross-sectional view and (b) a plan view. [Modes for carrying out the invention]

[0010] [First Embodiment] <Image Forming System> The schematic configuration of the image forming system equipped with the image forming apparatus of this embodiment will be described with reference to Figure 1. The image forming system 1X shown in Figure 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 that recording material S can be transferred between them.

[0011] In this embodiment, the finisher device 300 is a post-processing unit that can be retrofitted to the image forming apparatus 100 for functional expansion, and can perform post-processing described later on the recording material S on which the toner image has been fixed by the image forming apparatus 100. The image forming apparatus 100 and the finisher device 300 are connected to each other via a communication interface capable of serial and parallel communication, enabling data transmission and reception between them.

[0012] <Image forming apparatus> The image forming apparatus 100 is an electrophotographic tandem type full-color printer, and includes 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 by conveying a recording material S, and various members are arranged.

[0013] On the other hand, in the second housing 101b, various devices such as a fixing unit 800 that realizes a process of conveying the recording material S and fixing the toner image, and various members are arranged. 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 arranged. Note that an electrical unit (not shown) having a power supply board may be arranged on the back side of the first housing 101a and the second housing 101b. In the present embodiment, when the user operates the operation unit 200 to operate the image forming apparatus 100, the side where the user stands is called the "front", and the opposite side is called the "back". Also, the left side surface when viewed from the front is called the "left side surface", and the right side surface when viewed from the front is called the "right side surface".

[0014] The image forming apparatus 100 includes image forming parts 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 the present embodiment, an image forming unit 700 that forms a toner image on the recording material S is configured by the image forming parts 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 around 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 to be 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 containing the recording material S are arranged. These cassettes 10 contain 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, by the registration roller 12 rotating in synchronization with the toner image formed on the intermediate transfer belt 130, the recording material S is conveyed toward the secondary transfer unit T2. Note that, not limited to the recording material S accommodated in the cassette 10, the recording material S placed on a manual feeding unit (not shown) may be conveyed.

[0018] The image forming units Pa, Pb, Pc, Pd have substantially the same configuration except that the colors of the toner used for development 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, Pd will be omitted.

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

[0020] The process of forming, for example, a full-color image using the image forming apparatus 100 will now 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 charges the surface of the photosensitive drum 3a to a uniform potential by irradiating it with charged particles associated with corona discharge. Next, the photosensitive drum 3a is scanned and exposed by laser light corresponding to the image signal emitted from the exposure device La. As a result, 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 housed in the developing device 1a. In the developing devices 1a to 1d, the developer is circulated and transported while being agitated by a transport screw (not shown).

[0021] The toner image formed on the photosensitive drum 3a is transferred to the intermediate transfer belt 130 in a primary transfer section T1, which consists of the photosensitive drum 3a and a primary transfer roller 24a positioned on either side of the intermediate transfer belt 130. At this time, a primary transfer voltage is applied to the primary transfer roller 24a. After the primary transfer, any toner remaining on the surface of the photosensitive drum 3a is removed by a drum cleaning device 4a.

[0022] This process is performed sequentially in the yellow, magenta, cyan, and black image forming units Pa to Pd, superimposing the four toner images on the intermediate transfer belt 130. Subsequently, the recording material S contained in the cassette 10 is transported to the secondary transfer unit T2 in accordance with the toner image formation timing. 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 transferred to the recording material S all at once. Any toner remaining on the intermediate transfer belt 130 after the secondary transfer is removed by a belt cleaning device (not shown).

[0023] The recording material S onto which the toner image has been transferred is transported to the fuser unit 800. The fuser unit 800 fixes the toner image to the recording material S by applying heat and pressure to the recording material S onto which the toner image has been transferred. In this embodiment, it is possible to selectively apply heat and pressure to the recording material S by the first fuser 81 and then further apply heat and pressure by the second fuser 91. The fuser unit 800 can switch, using the fuser switching flapper 95, whether to transport the recording material S towards the second fuser 91 after passing through the first fuser 81, or to transport it while avoiding the second fuser 91 after passing through the first fuser 81.

[0024] The second fuser 91 is located downstream of the first fuser 81 in the transport direction of the recording material S. The second fuser 91 is used selectively for purposes such as adding gloss to the toner image on the recording material S fixed by the first fuser 81. For example, if the recording material S is coated paper such as glossy paper or synthetic paper, the recording material S that has passed through the first fuser 81 is transported along the fixing route 30a so that fixing occurs in both the first fuser 81 and the second fuser 91. On the other hand, if the recording material S is uncoated paper such as plain paper, the recording material S that has passed through the first fuser 81 is transported along the fixing bypass route 30b, which avoids the second fuser 91, so that fixing occurs in the first fuser 81 but not in the second fuser 91.

[0025] Since the first fuser 81 and the second fuser 91 described above may have the same configuration, the first fuser 81 will be used as an example for this explanation. The first fuser 81 has a fuser roller 82 (or fuser belt) that is rotatable and in contact with the surface of the recording material S on which the toner image is fixed, and a pressure belt 83 (or pressure roller) that presses against the fuser roller 82 to form a fuser nip. At least one of the fuser roller 82 and the pressure belt 83 is heated by a heater (not shown).

[0026] The first fuser 81 applies heat and pressure to the recording material S in the fuser nip section formed by the fuser roller 82 and the pressure belt 83 when gripping and transporting the recording material S on which the toner image has been formed, thereby fixing the toner image to the recording material S.

[0027] In this embodiment, the image forming apparatus 100 is capable of double-sided printing. In the case of single-sided printing, the recording material S on which the toner image has been fixed is transported to the discharge transport path 150 and discharged to the outside of the image forming apparatus 100. In the case of double-sided printing, the recording material S on which the toner image has been fixed is transported to the double-sided inversion transport path 600. The double-sided inversion transport path 600 is formed across the first housing 101a and the second housing 101b. In the double-sided inversion transport path 600, the recording material S is inverted by a switchback operation, and the front and back sides of the recording material S are swapped. The inverted recording material S is transported toward the registration roller 12, and the registration roller 12 transports it to the secondary transfer section T2 with the unprinted back side facing toward the intermediate transfer belt 130.

[0028] In the secondary transfer section T2, the full-color toner image formed on the intermediate transfer belt 130 is transferred in one go to the recording material S (back side). After that, the recording material S is fixed with toner by the fixing unit 800 and discharged to the outside of the image forming apparatus 100 with the side where the image was formed immediately before (image forming surface) facing upwards. The switching between the discharge transport path 150 and the double-sided inversion transport path 600 is performed by the transport switching flapper 160. In this embodiment, the fixing unit 800 is configured to have two fusers, but it may also be configured to have only one fuser. Furthermore, a cooling device for cooling the recording material S on which the toner image has been fixed by the fixing unit 800 may be provided in the second housing 101b.

[0029] A finisher device 300 is connected to the image forming apparatus 100 so as to be able to receive recording material S, and the recording material S discharged from the image forming apparatus 100 is transported to the finisher device 300.

[0030] The recording material S transported to the finisher device 300 undergoes post-processing by the finisher device 300, such as punching holes in the recording material S or stapling multiple sheets of recording material S together. In the finisher device 300, the punched recording material S is discharged to the upper discharge tray 301, and the bundles of stapled recording material S are discharged to the lower discharge tray 302.

[0031] Next, the airflow configuration for the outside air in the image forming apparatus 100 will be described. First, as a first embodiment, the airflow configuration for cooling the developing apparatuses 1a to 1d will be described. Figure 2 shows the image forming apparatus 100 with the front door open, and Figure 3 shows the image forming apparatus 100 with the front door closed.

[0032] As shown in Figure 2, the front of the first housing 101a is provided with a left front door 170a and a right front door 170b, which are exterior covers constituting at least a part of the exterior of the front side of the first housing 101a and are openable and closable as shown in the figure. In this embodiment, the left front door 170a and the right front door 170b have pivot axes extending vertically from different ends in the width direction (LR direction) of the first housing 101a, so they can be opened like double doors. The left front door 170a and the right front door 170b are examples of exterior covers that are opened when performing maintenance on the image forming section Pa to Pd.

[0033] In the vertical direction, a top cover 171, which constitutes at least a part of the top exterior of the first housing 101a, is provided above the left front door 170a, and air intake ports 175a to 175c are formed on the lower surface of the top cover 171. Here, the lower surface of the top cover 171 is an example of the opposing surface that faces the upper surface of the left front door 170a. In addition, filters 176a to 175c (Figure 8) are attached to the air intake ports 175a to 175c to collect dust and other foreign matter contained in the intake air in order to remove dust from the intake outside air. The detailed configuration around the air intake ports 175a to 175c will be described later. Here, the left front door 170a is an example of the first cover, and the top cover 171 is an example of the second cover.

[0034] Furthermore, an inner cover 173 is provided on the front of the first housing 101a, inside the left front door 170a and the right front door 170b. The inner cover 173 is intended to prevent users from accidentally touching movable parts or electrical wiring inside the first housing 101a when opening the left front door 170a and the right front door 170b. However, the inner cover 173 is detachably attached to the first housing 101a by screws or the like, so that service personnel can perform maintenance work.

[0035] The inner cover 173 has openings (not shown) that allow the image forming sections Pa to Pd (shown by dotted lines) to be individually inserted into and removed from the first housing 101a. Furthermore, the inner cover 173 is detachably provided with an inner cover duct unit 125, which will be described later.

[0036] As shown in Figure 3, a left-side intake unit 124 is provided on the left side of the interior of the first housing 101a, which has a fan (Figure 4) that draws in outside air from intake ports 175a to c. In this embodiment, the outside air drawn in from intake ports 175a to c is guided through the left-side intake unit 124 and the inner cover duct unit 125 towards the developing devices 1a to 1d in the image forming section Pa to Pd.

[0037] <Left-side intake unit> Next, the left intake unit 124 will be described using Figures 4 and 5. Figure 4 is a schematic diagram illustrating the airflow configuration for cooling the developing apparatus of this embodiment. Figure 5 is a schematic diagram illustrating the airflow configuration for cooling the developing apparatus of this embodiment, where (a) is a right side view showing the left intake unit and (b) is a left side view showing the left intake unit.

[0038] As shown in Figure 4, the left intake unit 124 has a left main body duct 174, a plurality of developing intake fans 180a, 180b, 180c, and 180d for cooling the developing devices 1a to 1d, and side ducts 174a and 174b, which will be described later. In this embodiment, the left intake unit 124 is supported by the first housing 101a. The left main body duct 174 is a duct with a space formed inside that communicates with the intake ports 175a to c.

[0039] On the right side of the left main body duct 174, as shown in Figure 5(a), developing intake fans 180b, 180c, and 180d and a side duct 174b are provided to cool the developing units 1b, 1c, and 1d. A communication section is formed on the right side of the left main body duct 174 that communicates with the developing intake fans 180b, 180c, and 180d, and outside air drawn in from the intake ports 175a to 175c in accordance with the operation of the developing intake fans 180b, 180c, and 180d passes through the inside of the left main body duct 174. Multiple developing ducts 181b, 181c, and 181d are formed inside the side duct 174b. The side duct 174b is connected to the developing intake fans 180b, 180c, and 180d so that outside air that has passed through the developing intake fans 180b, 180c, and 180d passes through the respective developing ducts 181b, 181c, and 181d.

[0040] On the other hand, on the left side of the left main body duct 174, a developing intake fan 180a and a side duct 174a are provided, as shown in Figure 5(b), in order to cool the developing apparatus 1a.

[0041] In this embodiment, charging intake fans 177a and 177b are provided to supply outside air to the charging devices 2a and 2b (Figure 1). A communication section is formed on the left side of the left main body duct 174, which communicates with the developing intake fan 180a and the charging intake fans 177a and 177b. As a result, outside air drawn in from the intake ports 175a to c in accordance with the operation of the developing intake fan 180a and the charging intake fans 177a and 177b passes through the inside of the left main body duct 174. The side duct 174a has a developing duct 181a and charging ducts 178a and 178b formed inside. The side duct 174a is connected to the developing intake fan 180a and the charging intake fans 177a and 177b so that outside air that has passed through the developing intake fan 180a and the charging intake fans 177a and 177b passes through the respective ducts 181a, 178a, and 178b.

[0042] The outside air drawn in from the intake ports 175a to c is then sent to the developing devices 1a to 1d via the left main body duct 174, developing intake fans 180a to 180d, developing ducts 181a to 181d, and the inner cover duct unit 125, as shown in Figure 4.

[0043] Figure 6(a) is a front cross-sectional view illustrating the airflow configuration of the developing apparatus 1a, and Figure 6(b) is a side cross-sectional view illustrating the airflow configuration of the developing apparatus 1a. Since the airflow of developing apparatuses 1b to 1c is substantially the same as that of developing apparatus 1a, this embodiment will be explained using developing apparatus 1a as an example.

[0044] As shown in Figure 6(a), the developing apparatus 1a has an upper sleeve 210a, a lower sleeve 211a, and transport screws 212a and 213a. The upper sleeve 210a and lower sleeve 211a carry the developer and rotate to supply the developer to the photosensitive drum 3a. The transport screws 212a and 213a circulate and transport the developer within the developing apparatus 1a while agitating it in opposite directions.

[0045] A developing and cooling duct 186a is provided above the developing apparatus 1a. Below the developing and cooling duct 186a and above the transport screw 212a, a heat sink 187 is provided, which has an elongated shape in the front-to-back direction (in the direction of the rotation axis of the transport screws 212a and 213a). The developing and cooling duct 186a is positioned to blow outside air onto the developing apparatus 1a on the side closer to the transport screws 212a and 213a than the upper sleeve 210a and lower sleeve 211a, with respect to the direction intersecting the rotation axis of the transport screws 212a and 213a.

[0046] Furthermore, as shown in Figure 6(b), the developing and cooling duct 186a is formed along the developing apparatus 1a with respect to the rotation axis direction of the transport screws 212a and 213a. The air that has passed through the outlet joint 184a is exhausted to the rear side of the apparatus through the developing and cooling duct 186a. At this time, the heat sink 187 is cooled by the airflow passing through the developing and cooling duct 186a. In this way, the heat sink 187, which is positioned above the transport screw 212a, is cooled, thereby indirectly cooling the developing apparatus 1a, which generates heat as the transport screws 212a and 213a rotate.

[0047] Furthermore, the outside air flowing near the developing unit 1a collects the scattered toner. In the image forming apparatus 100, toner is supplied from the developing units 1a to 1d to the photosensitive drums 3a to 3d to develop the toner image, but some toner (referred to as scattered toner) is scattered without being supplied to the photosensitive drums 3a to 3d.

[0048] As shown in Figure 6(a) above, in the developing apparatus 1a, for example, toner is supplied to the photosensitive drum 3a by the upper sleeve 210a and the lower sleeve 211a, but any excess toner that is not supplied to the photosensitive drum 3a is collected in the stirring chamber 214. However, some of the toner that is not supplied to the photosensitive drum 3a may be scattered outside the developing apparatus 1a without being collected in the stirring chamber 214. This scattered toner may contaminate the inside of the image forming apparatus 100 and cause image defects. Therefore, a toner collection unit is provided so that scattered toner can be sent to the toner collection unit by outside air and collected.

[0049] As shown in Figures 7(a) and 7(b), the toner recovery unit 400 has an exhaust duct 217a, a developing exhaust fan 214a, and a toner recovery filter 218a, and is located on the rear side (right side in Figure 7(a)) of the first housing 101a. The developing exhaust fan 214a and the toner recovery filter 218a are provided in the exhaust duct 217a. Below the lower sleeve 211a of the developing device 1a, a toner scattering recovery duct 215a is located. The toner scattering recovery duct 215a is formed to follow the rotation axis direction of the lower sleeve 211a. Multiple recovery ports are formed in the scattering recovery duct 215a, so that toner scattered below the lower sleeve 211a enters the scattering recovery duct 215a through these recovery ports.

[0050] The toner scattering collection duct 215a and the exhaust duct 217a of the toner collection unit 400 are connected by a scattering relay duct 216a. The outside air containing the above-mentioned scattered toner is discharged from the scattering collection duct 215a through the scattering relay duct 216a and exhaust duct 217a to the outside of the image forming apparatus 100 by the airflow generated by the developing exhaust fan 214a. The toner collection filter 218a is positioned in the middle of the flow path between the scattering relay duct 216a and the developing exhaust fan 214a. Therefore, toner is removed from the outside air as it passes through the toner collection filter 218a, and the toner-free air is discharged to the outside of the image forming apparatus 100.

[0051] <Air intake> Next, the air intake ports 175a to c will be explained using Figures 8 and 9. Figure 8(a) is a view of the front of the top cover 171 from below. Holders 179a to c, which hold filters 176a to c, are detachably attached to the air intake ports 175a to c. Figure 8(b) shows Figure 8(a) with only the holders 179a to c hidden. The filters 176a to c are installed so as to cover the air intake ports 175a to c in the area excluding the outer shape of the holders 179a to c. Therefore, when outside air passes through the filters 176a to c, dust particles larger than the mesh size of the filters 176a to c cannot pass through, thus preventing dust from entering the main unit. Therefore, by installing filters 176a to c, the intrusion of dust into the main unit can be reduced.

[0052] Furthermore, holders 179a to c hold filters 176a to c, and when replacing filters 176a to c, the filters 176a to c can be easily replaced by removing holders 179a to c from the air intake ports 175a to c.

[0053] Figure 9 shows a front view of the first housing 101a around the top cover 171. The air intakes 175a to 175c are located on the underside of the top cover 171 and directly above the left front door 170a, facing downwards. In other words, all of the air intakes 175a to 175c are located on the underside of the top cover 171, opposite the upper surface of the left front door 170a. In addition, a gap is formed between the upper surface of the left front door 170a and the underside of the top cover 171 in the vertical direction.

[0054] With this configuration, the first housing 101a can take in outside air from the air intake 175 through the gap located between the top cover 171 and the left front door 170a. The air drawn in from the air intakes 175a to 175c is then drawn into the left air intake unit 124 described above.

[0055] Furthermore, the air intake ports 175a to 175c are separated from the mounting surface 1Z of the first housing 101a by the length of the left front door 170a in the vertical direction. In this embodiment, the length of the left front door 170a in the vertical direction is longer than the length of the top cover 171 in the vertical direction, and is more than three times the vertical length of the top cover 171.

[0056] As described above, in this embodiment, the air intake port 175 is sufficiently far from the mounting surface 1Z of the first housing 101a, making it difficult to suck up dust accumulated on the mounting surface 1Z. Therefore, by using this configuration, it is possible to suppress the intake of dust into the image forming apparatus 100. In other words, it is possible to suppress dust from entering the developing devices 1a to d. Furthermore, it is possible to suppress image defects caused by dust and other foreign matter accumulating inside the image forming apparatus 100 and dust being mixed into the formed image.

[0057] Furthermore, because filters 176a to c are provided at the air intake ports 175a to c, even if air containing dust that has been stirred up from the ground surface 1Z is drawn in through the air intake ports 175a to c, it is possible to suppress the intake of dust into the image forming apparatus 100.

[0058] Furthermore, because the air intake ports 175 are located on the bottom side rather than the front side, the air intake ports 175a to c are less likely to be in the operator's line of sight, making it possible to position the air intake ports 175a to c without compromising the appearance quality.

[0059] Furthermore, the operating noise of fans and other components leaking from the air intake ports 175a-c is less audible with this configuration than when they are positioned facing the front of the enclosure 101a. Therefore, user discomfort due to noise can be reduced.

[0060] [Second Embodiment] Next, as a second embodiment, the airflow configuration of the charging devices 2a to 2b supported by the first housing 101a will be described. The airflow configuration of the charging devices 2c to 2d will be omitted from the description because outside air is taken in from different intake ports than the intake ports 175a to 175c.

[0061] Figure 10 shows the charging device 2a as a representative example. As shown in Figure 10, the charging device 2a charges the surface of the photosensitive drum 3a by ionizing the air surrounding the charging wire 203a through corona discharge and generating ions. Because ions are generated by ionizing the air, it is necessary to blow air into the charging device 2a. A primary intake duct 202a is provided near the charging device 2a to blow air into it.

[0062] Furthermore, the charging device 2a generates not only ions but also ozone during corona discharge. However, ozone needs to be recovered because it can easily corrode components of the charging device 2a, such as a stainless steel grid (not shown). Therefore, a primary exhaust duct 204a is provided near the charging device 2a to send the ozone to an ozone recovery filter 219a (see Figure 12(a)) via outside air for recovery.

[0063] The airflow configuration from the intake ports 175a-c to the left main body duct 174 is the same as in Figure 5(b). As shown in Figure 11, the air drawn in from the intake ports 175a-c is sent to the charging devices 2a-2b via the left main body duct 174, the charging intake fans 177a-177b, the charging ducts 178a-178b, and the inner cover duct unit 125. Furthermore, as the charging intake fans 177a and 177b operate, the air drawn in from the intake ports 175a-c passes through the primary intake ducts 202a and 202b described above and is blown to the charging devices 2a-2b.

[0064] In this way, the air drawn in from the intake ports 175a to 175c is blown to the charging devices 2a and 2b, so that the charging devices 2a and 2b can form an airflow that recovers the ozone generated by corona discharge to charge the photosensitive drums 3a and 3b.

[0065] Next, the exhaust airflow configuration in the charging devices 2a to 2d will be explained using Figures 12(a) and 12(b). Figures 12(a) and 12(b) show the exhaust airflow configuration in charging device 2a as a representative example. The exhaust airflow configuration in charging devices 2b to 2d is the same as that of charging device 2a, so the explanation will be omitted.

[0066] As shown in Figures 12(a) and 12(b), an ozone recovery unit 500 is located on the rear side (right side in Figure 12(a)) of the first housing 101a in order to remove the ozone generated by the corona discharge described above. The ozone recovery unit 500 has an exhaust duct 217a that can be used for toner recovery as described above, an exhaust fan 220a for charging, and an ozone recovery filter 219a. The exhaust fan 220a for charging and the ozone recovery filter 219a are provided in the exhaust duct 217a.

[0067] The primary exhaust duct 204a and the exhaust duct 217a of the ozone recovery unit 500 are connected by a charging relay duct 223a. The ozone-containing outside air is discharged from the primary exhaust duct 204a through the charging relay duct 223a and exhaust duct 217a to the outside of the image forming apparatus 100 by the airflow generated by the charging exhaust fan 220a.

[0068] The ozone recovery filter 219a is positioned in the middle of the flow path between the charging relay duct 223a and the charging exhaust fan 220a. As a result, ozone is removed from the outside air as it passes through the ozone recovery filter 219a, and the ozone-free air is discharged to the outside of the image forming apparatus 100.

[0069] Thus, the intake ports for drawing in air to be supplied to the charging devices 2a to 2b are the same as the intake ports 175a to c of the first embodiment described above. Therefore, the first housing 101a is able to take in outside air from the intake port 175 through the gap located between the top cover 171 and the left front door 170a.

[0070] Therefore, in this embodiment as well, the intake port 175 is sufficiently far from the mounting surface 1Z of the first housing 101a, making it difficult to suck up dust accumulated on the mounting surface 1Z. Thus, by using this configuration, it is possible to reduce the amount of dust taken into the first housing 101a.

[0071] In other words, it is possible to prevent dust from entering the charging devices 2a to d. Furthermore, it is possible to prevent foreign matter such as dust from accumulating inside the image forming apparatus 100 and to prevent image defects caused by dust contamination in the formed image. In addition, the filters 176a to c provided at the air intake ports 175a to c can prevent dust from entering the housing 101a.

[0072] Furthermore, because filters 176a to c are provided at the air intake ports 175a to c, even if air containing dust that has been stirred up from the ground surface 1Z is drawn in through the air intake ports 175a to c, it is possible to suppress the intake of dust into the image forming apparatus 100.

[0073] <Other Embodiments> In the embodiments described above, air intake ports for drawing air into the developing devices 1a to 1d and the charging devices 2a to 2b were explained, but the invention is not limited to these. For example, the configuration of the embodiments described above may be applied to cool the transport members that transport the recording material S after it has passed through the first fuser 81 and the second fuser 91 (Figure 1) using air intake ports 175a to c.

[0074] In the embodiments described above, an electrophotographic image forming apparatus 100 was used as an example, but the invention is not limited to this. For example, the embodiments described above may also be applied to heat-drying image forming apparatuses such as inkjet printers and dye-sublimation printers.

[0075] In the embodiment described above, a configuration was shown in which three intake ports 175a to c are provided facing downward in the vertical direction. However, a configuration with only one intake port or a configuration with four or more intake ports is also possible. For example, in this embodiment, a configuration may be shown in which only one intake port is provided that is long in the left-right direction (the width direction of the image forming apparatus 100) within the area where the intake ports 175a to c are provided.

[0076] Furthermore, although the above-described embodiment shows a configuration in which air intake ports 175a to c are provided on the top cover 171, the configuration is not limited to the above-described configuration as long as a similar effect can be obtained. For example, if there is another cover between the top cover 171 and the left front door 170a in the vertical direction, the air intake ports 175a to c may be provided on the other cover. In this case as well, by providing air intake ports 175a to c on the lower surface of the other cover that faces the upper surface of the left front door 170a, it is possible to suppress the intake of dust accumulated on the installation surface of the image forming apparatus 100 into the apparatus.

[0077] Furthermore, in the above-described embodiment, the holders 170a to c that hold the filters 176a to c are configured to be detachable from the air intake ports 175a to c. However, the filters 176a to c may be directly fixed to the air intake ports 175a to c. In this configuration, the lower part of the top cover 171 may be configured as a replacement unit for replacing the filters 176a to c. [Explanation of symbols]

[0078] Pa~Pd Image Forming Unit 1a~1d Developing equipment 2a~2d Charging device 3a~3d Photosensitive drum 100 Image forming apparatus 170a Left front door 170b Right front door 171 Top cover 175a~c Air intake 176a~c Filter 179a~c Holder

Claims

1. An image forming apparatus for forming an image on a recording material, An image forming unit having a photoreceptor, a charging unit that charges the photoreceptor by corona discharge, and a developing unit that develops the electrostatic latent image formed on the photoreceptor using toner, A first cover which constitutes at least a part of the front exterior of the image forming apparatus, A second cover is provided above the first cover in the vertical direction and has an opposing portion that faces the upper surface portion of the first cover, The air intake port provided on the opposing part of the second cover, The system includes a fan that draws in air from the gap between the opposing portion and the upper portion, through the air intake, to supply air to the image forming portion. An image forming apparatus characterized by the following features.

2. The system further includes a filter for collecting foreign matter contained in the air drawn in from the aforementioned air intake. The image forming apparatus according to feature 1.

3. The system further includes a holder that holds the filter and is detachable from the air intake port. The image forming apparatus according to feature 2.

4. The system further includes a developing duct that guides the air drawn in by the fan to the developing unit. The image forming apparatus according to any one of claims 1 to 3.

5. The system further includes a charging duct that guides the air drawn in by the fan to the charging unit. The image forming apparatus according to any one of claims 1 to 3.

6. Another fan that draws in outside air through the aforementioned intake port, further comprising another fan different from the aforementioned fan, The system further comprises a charging duct that guides the air drawn in by the other fan to the charging unit. The image forming apparatus according to feature 4.

7. The second cover constitutes at least a part of the exterior on the top side of the image forming apparatus. The image forming apparatus according to any one of claims 1 to 6.

8. The first cover can be opened and closed when performing maintenance on the image forming unit. The image forming apparatus according to any one of claims 1 to 7.

9. In the vertical direction, the length of the first cover is longer than the length of the second cover. The image forming apparatus according to any one of claims 1 to 8.

Images