Image forming apparatus and blower

Abstract

To provide an air blowing device that can reduce an air flow sound generated in association with the operation of a fan with a configuration simpler than a conventional configuration.SOLUTION: As a duct, a silent duct 710 is used, which is formed with a plurality of sound absorption holes 711 and has a sound absorption sheet 715 covering the plurality of sound absorption holes 711. When a part of an air flow sound generated in association with the operation of an image formation exhaust fan 410 passes through the sound absorption holes 711, a part of the energy of the sound changes to thermal energy, and thereby the air flow sound is reduced. The sound absorption sheet 715 further changes the part of the energy of the sound passing through the sound absorption holes 711 to thermal energy, and thereby the air flow sound is further reduced. An air flow with the air flow sound thus reduced by the silent duct 710 is exhausted from a duct outflow port 721. Consequently, a reduction in the air flow sound generated in association with the operation of a fan can be achieved with a simple configuration.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a blower suitable for use in image forming apparatus such as printers, copiers, facsimile machines, or multifunction devices, and to an image forming apparatus equipped therewith. [Background technology]

[0002] Image forming apparatuses are equipped with a ventilation device that is installed inside the casing to blow air, for example, to collect ozone generated by the charging of the photosensitive drum or toner scattered inside the machine using a filter, or to expel heat generated during operation to the outside of the machine. The ventilation device has a fan that generates airflow and a cylindrical duct. The duct connects the fan to various devices such as a corona charger that generates ozone, a developer that generates scattered toner, a fuser that becomes hot, and a power supply, forming an air passage through which the airflow generated by the fan passes.

[0003] Incidentally, the airflow noise generated by the operation of a fan is an unpleasant sound for the user. Therefore, it has been conventionally proposed to reduce airflow noise by providing multiple ducts of different lengths, or by providing hollow tubular side branches with closed ends in the ducts, so that the sounds passing through them interfere with each other (Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-156367 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, in recent years there has been a demand for further miniaturization of image forming machines, and there is limited space for installing fans and ducts within the machine. Therefore, it has been difficult to use multiple ducts of different lengths or ducts with side branches, as described above, in order to reduce airflow noise by interfering with sound.

[0006] This invention has been made in view of the above problems, and aims to provide a blower that can reduce the noise of airflow generated in conjunction with the operation of a fan, with a simpler configuration than conventional configurations. [Means for solving the problem]

[0007] An embodiment of the present invention is a blower that is disposed inside a housing and blows air, comprising a fan that generates airflow, an inlet through which air flows in as the fan operates, an outlet through which the air that has flowed in from the inlet flows out, and a duct that forms an air passage through which the air that has flowed in from the inlet passes to the outlet, wherein the main body has a perforated wall surface formed with a plurality of through holes that connect the inside and outside of the main body, and a sound-absorbing member having sound-absorbing properties is disposed on the outer surface of the perforated wall surface of the main body so as to cover the plurality of through holes. [Effects of the Invention]

[0008] According to the present invention, the noise generated by the operation of the fan can be quieted with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing an image forming apparatus to which the blower device of this embodiment can be applied. [Figure 2] (a) Cross-sectional view showing the image forming transfer apparatus, (b) Enlarged view showing the image forming section. [Figure 3] Rear view showing the airflow unit. [Figure 4] A block diagram showing an example of fan airflow. [Figure 5](a) Front view showing the appearance of the image forming transfer device, (b) Right side view showing the appearance of the image forming transfer device. [Figure 6] Perspective view showing the back side of the duct unit. [Figure 7] Perspective view showing the front side of the duct unit. [Figure 8] Perspective view showing the fan and the soundproof duct. [Figure 9] Cross-sectional view showing the fan and the soundproof duct. [Figure 10] Perspective view showing the soundproof duct with the sound-absorbing sheet attached. [Figure 11] Top view showing the attachment area of the sound-absorbing sheet to the soundproof duct. [Figure 12] Graph showing the magnitude of the airflow sound when using the soundproof duct and when using a duct without sound-absorbing holes. [Figure 13] Schematic diagram showing a conventional duct provided with a side branch.

Mode for Carrying Out the Invention

[0010] <Image Forming System> Hereinafter, this embodiment will be described. First, an image forming apparatus to which the blower device of this embodiment is applicable will be described with reference to FIGS. 1 to 2(b). The image forming system 1X shown in FIG. 1 includes an image forming apparatus 101, a large-capacity feeder 106 having a plurality of recording material storage units, and a sensing device 107. With respect to the conveyance direction of the recording material S by the large-capacity feeder 106 (from right to left in FIG. 1), the sensing device 107 is disposed on the downstream side of the image forming apparatus 101.

[0011] In this specification, the side where the user stands when operating the operation unit 80 described later is referred to as "front (or front)", and the opposite side is referred to as "back (or rear)". Also, the left when viewed from the front is referred to as "left", and the right when viewed from the front is referred to as "right". Therefore, FIG. 1 shows the image forming system 1X when viewed from the front.

[0012] For the image forming apparatus 101, the high-capacity feeder 106 and the sensing device 107 are not only physically connected so as to be able to convey the recording material S, but also electrically connected so as to be able to transmit and receive electrical signals. The high-capacity feeder 106 is a device that supplies the recording material S to the image forming apparatus 101. The sensing device 107 is a device that reads the toner image after fixing formed on one or both sides of the recording material S discharged from the image forming apparatus 101 and feeds back the same to the image forming apparatus 101 as an image signal. In the image forming apparatus 101, the deviation of the image density and the image position is detected based on the fed-back image signal, and the image data is corrected based on the detected deviation of the image density and the image position. Then, based on the corrected image data, the image forming units 200Y to 200K are controlled to form a toner image on the recording material S.

[0013] Note that, on the upstream side in the recording material conveyance direction of the image forming apparatus 101, instead of the high-capacity feeder 106, a manual feeder (not shown), a long feeder capable of accommodating a long recording material, etc. can be selectively connected. Alternatively, on the further upstream side of the high-capacity feeder 106, a high-capacity feeder (not shown), a manual feeder, a long feeder, etc. can be selectively connected in series. Also, on the further downstream side of the image forming apparatus 101 or the sensing device 107, although not shown, one or a plurality of various post-processing devices such as an inserter, a puncher, a bookbinding machine, a high-capacity stacker, a folding machine, a finisher, a trimmer, etc. can be selectively connected in combination. Thus, by selectively connecting various option devices upstream and downstream of the image forming apparatus 101, it becomes possible to output in-line the products obtained by performing various post-processing on the recording material S of various materials, and an image forming system 1X with high productivity, high image quality, high stability, and high functionality can be provided.

[0014] <Image Forming Apparatus> The image forming apparatus 101 is broadly divided into an image forming transfer apparatus 500 and a fixing and transport apparatus 600, which are configured as separate units. In this embodiment, the image forming transfer apparatus 500, which serves as an image forming means, includes image forming units 200Y, 200M, 200C, 200K, an intermediate transfer belt unit 800, etc., which realize the transfer process of transferring a toner image onto the recording material S. On the other hand, the fixing and transport apparatus 600 includes a fuser 8, a cooler 302, etc., which realize the fixing process of fixing the toner image onto the recording material S. The image forming transfer apparatus 500 and the fixing and transport apparatus 600 are connected so as to be able to transfer the recording material S.

[0015] The image forming and transfer apparatus 500 and the fixing and transport apparatus 600 each have independent housings 500A and 600A, and are movable by multiple casters provided on each. This makes it possible to pack and transport the image forming and transfer apparatus 500 and the fixing and transport apparatus 600 separately, even if they are large devices, improving work efficiency up to installation. Housing 500A is equipped with a document reading device 160 for reading image information from the original, and an operation unit 80 which has a display unit capable of displaying various information and keys for inputting various information according to user operation.

[0016] The housings 500A and 600A are each composed of a front panel on the front side, a rear panel located on the rear side that supports the image forming section 200Y~200K, intermediate transfer belt unit 800, fuser 8, cooler 302, etc. together with the front panel, and multiple frames such as pillars that connect the front panel and the rear panel or support the front panel. These housings 500A and 600A are fitted with resin exterior covers that constitute the exterior. Note that the image forming transfer apparatus 500 and the fuser transport apparatus 600 may be housed in a single housing instead of separate housings (500A, 600A).

[0017] <Image Forming and Transfer Apparatus> Next, the image forming transfer apparatus 500 will be described using Figures 2(a) and 2(b). The image forming transfer apparatus 500 is an intermediate transfer type apparatus in which image forming units 200Y, 200M, 200C, and 200K, which form yellow, magenta, cyan, and black toner images housed inside the housing 500A (inside the housing), are arranged facing the intermediate transfer belt 208. The image forming transfer apparatus 500 forms toner images on the recording material S according to image data from an original document reading device 160 (see Figure 1) located above the housing 500A, or from an external device (not shown) such as a personal computer. Examples of recording material S include paper, plastic film, cloth, and other sheet materials.

[0018] The transport process for the recording material S in the image forming transfer apparatus 500 will now be described. The recording material S is housed in one or more (two in this case) cassettes 212 and is supplied one sheet at a time by the supply roller 220 in accordance with the image forming timing. The recording material S supplied by the supply roller 220 is transported to the registration roller 213 located in the middle of the transport path 250. There, the registration roller 213 corrects the skewness and timing of the recording material S and sends the recording material S to the secondary transfer section ST. The secondary transfer section ST is formed by the secondary transfer inner roller 214 and the secondary transfer outer roller 215 facing each other on either side of the intermediate transfer belt 208, and is a transfer nip section that transfers a toner image from the intermediate transfer belt 208 onto the recording material S by applying a predetermined pressure and secondary transfer voltage.

[0019] Next, we will explain the image formation process that takes place at the same timing as the transport process of the recording material S to the secondary transfer unit ST described above. First, we will explain the image forming units 200Y to 200K. However, since the image forming units 200Y to 200K for each color are basically the same except for the toner color, we will use the black image forming unit 200K as an example below.

[0020] The image forming unit 200K includes a photosensitive drum 201K, a charger 202K, a laser scanner 203K, a developer 204K, and the like. The surface of the rotating photosensitive drum 201K is uniformly pre-charged by the charger 202K, and then an electrostatic latent image is formed by the laser scanner 203K, which is driven based on the image data. Next, the developer 204K develops the electrostatic latent image formed on the photosensitive drum 201K with toner contained in the developer, and a toner image is formed on the photosensitive drum 201K.

[0021] Subsequently, a predetermined pressure and primary transfer voltage are applied by the primary transfer roller 207K, which is positioned opposite the image forming unit 200K and the intermediate transfer belt 208, and the toner image formed on the photosensitive drum 201K is primary transferred onto the intermediate transfer belt 208. The primary transfer residue toner remaining on the photosensitive drum 201K after the primary transfer is removed by the drum cleaner 209K. The removed primary transfer residue toner is collected in the toner recovery container 211 via the toner recovery path 210.

[0022] The intermediate transfer belt 208 is an endless belt that is tensioned by multiple tension rollers and secondary transfer internal rollers 214, and is moved by a motor (not shown) or the like at a speed corresponding to the rotation speed of the photosensitive drums 201Y to 201K. The image formation process for each color, which is processed in parallel by the image forming units 200Y to 200K for each color as described above, is performed at the timing when the toner images of the colors that were primary transferred upstream in the direction of movement are sequentially superimposed on the intermediate transfer belt 208. As a result, a full-color toner image is ultimately formed on the intermediate transfer belt 208 and transported to the secondary transfer unit ST. The secondary transfer residue toner remaining on the intermediate transfer belt 208 after passing through the secondary transfer unit ST is recovered from the intermediate transfer belt 208 by a belt cleaner device 216. The primary transfer rollers 207Y to 207K, the intermediate transfer belt 208, multiple tension rollers, secondary transfer internal rollers 214, belt cleaner device 216, etc. may be provided integrally as an intermediate transfer belt unit 800.

[0023] Through the above transport and image formation processes, the timing of the recording material S and the toner image are synchronized in the secondary transfer section ST, and a secondary transfer is performed in which the toner image is transferred from the intermediate transfer belt 208 to the recording material S. Subsequently, the recording material S is transported to the fixing transport device 600 by the pre-fixing transport belts 217a and 217b, and the fixing transport device 600 fixes the toner image to the recording material S.

[0024] The image forming and transfer apparatus 500 can perform full-color image formation using all of the image forming units 200Y to 200K described above, as well as black and white image formation using only the black image forming unit 200K. During black and white image formation, the primary transfer rollers 207Y to 207C and the primary transfer auxiliary roller 218 are displaced vertically downward by a separation mechanism (not shown). This separates the photosensitive drums 201Y to 201C and the intermediate transfer belt 208, stopping the image forming units 200Y to 200C. By stopping the image forming units 200Y to 200C in this way, unnecessary wear on parts due to driving is prevented, thereby extending the lifespan of the image forming units 200Y to 200C.

[0025] In the image forming unit 200K, which is not separated from the intermediate transfer belt 208, the photosensitive drum 201K is configured with a larger diameter than the photosensitive drums 201Y to 201C, which is suitable for extending its lifespan. Furthermore, the charger 202K of the image forming unit 200K is a non-contact charging type corona charger, while the chargers 202Y to 202C of the image forming units 200Y to 200C are contact charging type roller chargers using charging rollers. As a result, even for users who frequently use black and white image forming, the maintenance interval of the frequently used image forming unit 200K is not shorter than that of the less frequently used image forming units 200Y to 200C, but remains almost the same for both. In addition, the large-diameter drum configuration using a corona charger allows for a wider charging width in the direction of the rotation axis of the photosensitive drum compared to the small-diameter drum configuration using a roller charger, and is a configuration suitable for high-speed charging, thus improving productivity during black and white image forming.

[0026] In the image forming transfer apparatus 500 in which the image forming units 200Y~200C and the image forming unit 200K have slightly different configurations, differences in shape and wear may occur in the amount of toner charged to the photosensitive drums 201Y~201C and the photosensitive drum 201K. If there is a difference in the amount of toner charged, the transfer of the toner image from the intermediate transfer belt 208 to the recording material S in the secondary transfer process may not be performed uniformly, potentially resulting in transfer defects. Therefore, the photosensitive drum 201K is equipped with a pre-transfer charger 219 consisting of a corona charger to equalize the amount of toner charged to the photosensitive drums 201Y~201C. The pre-transfer charger 219 controls the charge (specifically, applies charge) to the photosensitive drum 201K before it reaches the transfer nip formed by the photosensitive drum 201K and the primary transfer roller 207K, thereby equalizing the amount of toner charged to the toner image formed on the photosensitive drum 201K.

[0027] With the configuration described above, an image forming and transfer apparatus 500 is provided that excels in high productivity, high image quality, high stability, and long lifespan, not only in full-color image formation but also in monochrome image formation.

[0028] <Fusing and conveying device> Next, the fixing and transport device 600 will be described. As shown in Figure 1, the fixing and transport device 600 has a fixing unit 8 and a cooler 302. The fixing unit 8 has a fixing roller 8a that is heated by a heater (not shown) and a pressure roller 8b that pressurizes the recording material S against the fixing roller 8a. The recording material S, on which a toner image has been formed, is transported from the image forming transfer device 500 and heated and pressurized while being held and transported in a fixing nip section N1 formed by the fixing roller 8a and the pressure roller 8b. As a result, the toner image is fixed to the recording material S.

[0029] Here, a fuser 8 consisting of a pair of rollers, a fuser roller 8a and a pressure roller 8b, is shown as an example, but the example is not limited to this. For example, a fuser may have a fuser belt instead of a fuser roller 8a, and the recording material S may be heated and pressurized while being held and transported by a fuser nip formed by the fuser belt, which is heated by a heater, and the pressure roller 8b, thereby fixing a toner image to the recording material S.

[0030] The recording material S, heated by the fuser 8, is conveyed towards the cooler 302. The cooler 302 has cooling belts 302a and 302b and a heat sink 303. The cooling belts 302a and 302b are in contact with each other to form a cooling nip section N2 that grips and conveys the recording material S. The heat sink 303 is in contact with the inner circumferential surface of the cooling belt 302a, and the heat sink 303 cools the cooling belt 302a. As a result, the recording material S, heated by the fuser 8, is cooled when it is gripped and conveyed in the cooling nip section N2.

[0031] The recording material S, cooled by the cooler 302, is held between a pair of cooling outlet rollers 601 and transported. In single-sided mode, where a toner image is formed on only one side of the recording material S, the recording material S, cooled by the cooler 302, is guided to the discharge transport path 304 and discharged from the housing 600A toward the sensing device 107. On the other hand, in double-sided mode, where a toner image is formed on both sides of the recording material S, the recording material S, cooled by the cooler 302, is inverted in the inversion transport path 305 and then returned to the image forming transfer device 500 via the double-sided transport path 306. Thereafter, the recording material S undergoes the same process as in single-sided mode, with a toner image formed on the other side by the fuser 8, and after being cooled by the cooler 302, it is guided to the discharge transport path 304 and finally discharged from the housing 600A toward the sensing device 107.

[0032] <Airflow Unit> Next, the airflow units installed in the housings 500A and 600A of the image forming apparatus 101 to supply air will be explained using Figures 3 and 4, with reference to Figures 1 to 2(b). First, the airflow units of the image forming transfer apparatus 500 will be explained. As shown in Figure 3, the airflow units of the image forming transfer apparatus 500 include an image-forming airflow 401, a pre-fixing transport airflow 402, and a power supply airflow 403.

[0033] An example of a blower (exhaust) system, the image-forming airflow 401, includes a charger intake fan 408, developer intake fans 409Y, 409M, 409C, an image-forming exhaust fan 410, and a duct unit 700. The charger intake fan 408 supplies outside air for ventilation to the charger 202K. A charger intake filter 411, which collects airborne dust in the outside air, is positioned at the intake port of the charger intake fan 408 to supply purified air to the charger 202K. The airflow of the charger intake fan 408 is, for example, 0.27 m³. 3 It is " / min".

[0034] The developer intake fans 409Y, 409M, and 409C supply outside air for cooling to the developer units 204Y, 204M, and 204C. The airflow of the developer intake fans 409Y to 409C is, for example, 0.11 m³. 3 It is " / min".

[0035] The image formation exhaust fan 410 expels ozone, a dischargeable substance generated by corona discharge performed by the charger 202K and the pre-transfer charger 219, from the image forming unit 200K. The image formation exhaust fan 410 also expels heat generated in the developer units 204Y, 204M, and 204C due to friction during rotational drive from the image forming unit 200. Furthermore, the image formation exhaust fan 410 expels heat accumulated inside the toner recovery path 210. In this embodiment, polyester resin is used for the toner binder resin, and if the temperature near the developer units 204Y~204C exceeds 40°C, image defects may occur, and if the temperature near the toner recovery path 210 exceeds 45°C, toner clogging may occur. Therefore, in this embodiment, heat is expelled to keep the temperature near the developer units 204Y~204C below 40°C and the temperature near the toner recovery path 210 below 45°C. Furthermore, the image formation exhaust fan 410 discharges the scattered toner from the image formation unit 200Y~200K during the image formation process. The airflow of the image formation exhaust fan 410 is, for example, 1.13 m³. 3 The airflow of the image exhaust fan 410 is the sum of the airflow of the charger intake fan 408 and the developer intake fans 409Y, 409M, and 409C, which is 0.60 m³. 3Larger than " / min"

[0036] Upstream of the image-forming exhaust fan 410 in the airflow direction (arrow Y direction), an image-forming exhaust filter 412 is installed to collect ozone and scattered toner discharged from the image forming unit 200Y~200K. By collecting ozone and scattered toner in the image-forming exhaust filter 412, ozone and scattered toner are prevented from being discharged outside the housing 500A.

[0037] In this embodiment, the airflow generated by the charger intake fan 408, developer intake fans 409Y~409C, and image exhaust fan 410 is discharged outside the housing 500A (outside the housing) through a cylindrical duct unit 700 provided inside the housing 500A. The image exhaust filter 412 is located inside the duct unit 700. The duct unit 700 will be described later (see Figures 6 and 7).

[0038] According to the image-forming airflow 401 described above, ozone, scattered toner, and heat can be efficiently discharged outside the housing 500A without accumulating inside the housing 500A. Therefore, it is possible to prevent charging defects such as uneven charging caused by ozone and scattered toner adhering to the photosensitive drum and charger, development defects caused by toner overheating and deterioration of fluidity, malfunctions such as toner transport path clogging, and transfer defects caused by ozone and scattered toner adhering to the pre-transfer charger 219.

[0039] On the inner circumference of the pre-fixing transport belts 217a and 217b, pre-fixing transport suction fans 413 are provided to adsorb the recording material S to the outer surface of the pre-fixing transport belts 217a and 217b via suction ports directed toward the pre-fixing transport belts 217a and 217b. For example, two pre-fixing transport suction fans 413 are arranged in the transport direction for each of the pre-fixing transport belts 217a and 217b, for a total of four fans. These pre-fixing transport suction fans 413 constitute the pre-fixing transport airflow 402. The pre-fixing transport suction fans 413 are adjusted to the optimal airflow according to the material and shape of the transported recording material S by a control circuit (not shown). With this configuration, stable transport of recording material S of various materials can be performed without disturbing the toner image on the recording material S before fixing. The airflow of the pre-fixing transport suction fans 413 is, for example, 0.25 m³. 3 It is " / min".

[0040] The power supply airflow 403 has a power supply exhaust fan 415 that expels heat generated on the power supply board 414 to the outside of the housing 500A. As the power supply exhaust fan 415 exhausts air, outside air for cooling is supplied from the power supply intake port 416, allowing the power supply board 424 to be cooled efficiently. This configuration prevents malfunctions and failures of the image forming transfer apparatus 500 caused by overheating of the power supply board 414 and a decrease in output. The airflow of the power supply exhaust fan 415 is, for example, 1.23 m³. 3 It is " / min".

[0041] Next, the airflow unit of the fixing and conveying device 600 will be described. As shown in Figure 3, the airflow unit of the fixing and conveying device 600 includes a fixing airflow 404, a cooler airflow 405, a power supply airflow 406, and an electrical equipment airflow 407. The fixing airflow 404 has a fixing heat exhaust fan 417, a fixing pressurized intake fan 418, a fixing pressurized exhaust fan 419, and a moisture exhaust fan 420.

[0042] The fixing exhaust fan 417 mainly discharges the heat generated in the fixing roller 8a of the fixing unit 8 to the outside of the housing 600A. In the case of this embodiment, three fixing exhaust fans 417 are arranged side by side in the left - right direction. And when the release agent (such as wax) contained in the components constituting the fixing unit 8 or toner is heated, VOC (Volatile Organic Compounds), UFP (Ultra Fine Particle), etc. may be generated. Therefore, a fixing upper exhaust filter 421 for collecting VOC, UFP, etc. is disposed on the downstream side (here, the back side) of the air flow generated by the fixing exhaust fan 417. The air volume of the fixing exhaust fan 417 is, for example, "0.55m 3 / min".

[0043] The fixing pressurization intake fan 418 supplies outside air for cooling to the pressurization roller 8b of the fixing unit 8. The fixing pressurization exhaust fan 419 discharges the heat generated on the pressurization roller 8b side of the fixing unit 8 to the outside of the housing 600A. The moisture exhaust fan 420 discharges the water vapor that may be generated when the recording material S containing moisture is heated by the fixing unit 8 to the outside of the housing 600A. The air volume of the fixing pressurization intake fan 418 is, for example, "1.74m 3 / min", and the air volume of the fixing pressurization exhaust fan 419 is, for example, "0.50m 3 / min". The air volume of the moisture exhaust fan 420 is, for example, "0.28m 3 / min".

[0044] A fixing lower exhaust filter 422 for collecting VOC, UFP, etc. is disposed on the downstream side (here, the left side) of the air flow direction of the air flows generated by the fixing pressurization exhaust fan 419 and the moisture exhaust fan 420.

[0045] Note that the above - mentioned pre - fixing conveyance suction fan 413 may suck VOC, UFP, etc. from the housing 600A into the housing 500A. Therefore, in this embodiment, the fixing lower exhaust filter 422 is also used to collect VOC, UFP, etc. from the air sucked by the pre - fixing conveyance suction fan 413.

[0046] With the configuration of the fuser airflow 404 described above, heat, moisture, VOCs, UFPs, etc. generated during the fuser process can be efficiently discharged outside the casing 600A without accumulating inside the casing 600A. In other words, it is possible to prevent fuser failures and malfunctions caused by heat accumulating inside the casing 600A and causing the toner and components to overheat.

[0047] Furthermore, excessive heat supplied to the toner during the fixing process due to overheating of the pressure roller 8b of the fuser unit 8 can prevent fixing failures, or poor separation of the recording material S from the fuser roller 8a and pressure roller 8b. In addition, condensation on the transport guide (not shown) due to the adhesion of water vapor, and transport and fixing failures caused by condensed water droplets adhering to the recording material S during transport can be prevented. Moreover, malfunctions and transport failures caused by the release agent (wax) vaporized by heating solidifying again and adhering to parts can be prevented.

[0048] The cooler airflow 405 has a cooler exhaust fan 423 for discharging the heat released by the heat sink 303 of the cooler 302 to the outside of the housing 600A. The heat sink 303 of the cooler 302 is a heat exchanger that absorbs heat from the fixed recording material S via the cooling belt 302a and releases the absorbed heat. With this configuration, the recording material S heated in the fuser 8 is efficiently cooled, so the amount of heat dissipated from the recording material S in the transport path (304, 305, 306, see Figure 1) can be reduced. In other words, it is possible to prevent image defects and malfunctions caused by the toner overheating due to heat dissipation from the recording material S. In addition, when a large number of deliverables are loaded in the post-processing device (here, the sensing device 107), it is possible to prevent the recording materials S from sticking together via the toner.

[0049] The power supply airflow 406 includes power supply exhaust fans 425 and 426 that expel heat generated on the power supply board 424 to the outside of the enclosure 600A. As the power supply exhaust fans 425 and 426 exhaust air, cooling air is supplied from the power supply intake port 427, allowing the power supply board 424 to be cooled efficiently. This configuration prevents malfunctions and failures caused by the power supply board 424 overheating and resulting in reduced output.

[0050] The electrical airflow 407 is equipped with an electrical exhaust fan 430 that expels heat generated on the electrical circuit boards 428 and 429 to the outside of the enclosure 600A. As the electrical exhaust fan 430 exhausts the air, cooling air is supplied from the electrical intake port 431, allowing the electrical circuit boards 428 and 429 to be cooled efficiently. This prevents malfunctions and failures that may occur due to overheating of the electrical circuit boards 428 and 429, which would otherwise reduce their output.

[0051] <Duct Unit> Next, the duct unit 700 will be described using Figures 5(a) to 7 with reference to Figures 2(a) to 3. As shown in Figures 5(a) and 5(b), the housing 500A is fitted with resin exterior covers (60a to 60e) that cover the housing 500A and constitute the exterior. In this embodiment, the exterior covers include a front cover 60a on the front, a right side cover 60b on the right side, a left side cover 60c on the left side, a top cover 60d on the top, and a rear cover 60e on the back. In order to take in air into the housing 500A, an air intake port 61 is formed in the front cover 60a and an air intake port 62 is formed in the right side cover 60b.

[0052] The developer intake fans 409Y~409C described above draw air into the housing 500A from outside the housing 500A via the intake port 61. The charger intake fan 408 draws air into the housing 500A from outside the housing 500A via the intake port 62 and blows the drawn air from above the charger 202K toward the photosensitive drum 201K.

[0053] In this embodiment, a duct unit 700 is provided inside the housing 500A to combine and discharge the airflow generated by the charger intake fan 408, the airflow generated by the developer intake fans 409Y~409C, and the airflow generated by the image exhaust fan 410. However, when multiple airflows are combined, if the confluence points of the multiple airflows overlap and the pressure loss increases, there is a risk that the overall exhaust efficiency will decrease. Therefore, in this embodiment, a duct unit 700 is used that can combine multiple airflows while suppressing a decrease in exhaust efficiency.

[0054] As shown in Figures 6 and 7, the duct unit 700 includes a developing exhaust duct 701, an ozone exhaust duct 702, an image-making exhaust duct 703, and a noise-reducing duct 710. In this embodiment, the duct located downstream of the image-making exhaust fan 410 in the airflow direction is a different type of noise-reducing duct 710 than conventional ducts. The noise-reducing duct 710 will be described later (see Figures 8 to 11).

[0055] The developing exhaust duct 701 is formed by integrally providing a developing exhaust section 701a and a cooling exhaust section 701b using resin. The developing exhaust section 701a has developing exhaust ports 71Y, 71M, and 71C. The developing exhaust ports 71Y to 71C are formed at positions corresponding to the developing units 204Y to 204C so that air passing near the developing units 204Y, 204M, and 204C due to intake by the developing unit intake fans 409Y, 409M, and 409C can be taken into the developing exhaust section 701a. In other words, air near the developing units 204Y to 204C flows from the developing exhaust ports 71Y to 71C into the developing exhaust section 701a, and the developing exhaust section 701a merges with the air flowing from the developing exhaust ports 71Y to 71C. The vicinity of the developing units 204Y to 204C refers to the area around the developing units 204Y to 204C through which air drawn in by the developing unit intake fans 409Y to 409C flows.

[0056] The cooling exhaust section 701b has a pre-transfer charging exhaust port 72 and an image cooling port 73. The pre-transfer charging exhaust port 72 is formed to take in air containing ozone generated by the pre-transfer charger 219 from the vicinity of the pre-transfer charger 219 into the cooling exhaust section 701b. The image cooling port 73 is formed to take in air from the vicinity of the toner recovery path 210 into the cooling exhaust section 701b. In this embodiment, air flows into the cooling exhaust section 701b from the pre-transfer charging exhaust port 72 and the image cooling port 73 as the image exhaust fan 410 operates. The vicinity of the pre-transfer charger 219 is the area around the pre-transfer charger 219 from which air is exhausted as the image exhaust fan 410 operates. The vicinity of the toner recovery path 210 is the area around the toner recovery path 210 from which air is exhausted as the image exhaust fan 410 operates. The formation of an airflow within the cooling exhaust section 701b allows the ozone generated by the pre-transfer charger 219 to be captured by the image exhaust filter 412, and also allows the heat accumulated in the toner recovery path 210 to be discharged.

[0057] In this manner, the developing exhaust duct 701 combines the air taken in from the developing exhaust ports 71Y~71C, the pre-transfer charging exhaust port 72, and the developing cooling port 73 using a single imaging exhaust fan 410, and then passes it through the imaging exhaust filter 412. This reduces the number of fans, thereby enabling space saving in the housing 500A.

[0058] The ozone exhaust duct 702 is a duct for taking in air containing ozone generated by the charger 202K from the vicinity of the charger 202K. The image development exhaust duct 703 is a separate duct for combining the airflow from the development exhaust duct 701 and the airflow from the ozone exhaust duct 702 into a single airflow.

[0059] In this embodiment, despite the relatively small opening areas of the developing exhaust ports 71Y~71C, the pre-transfer charging exhaust port 72, and the image cooling port 73, a high-static-pressure sirocco fan is used for the image exhaust fan 410 in order to efficiently draw air from the narrow space. A sirocco fan is a multi-blade blower with many rectangular fins attached in a circular shape, and because it can produce high static pressure even in a small size, it can generate a large airflow. The image exhaust fan 410 is located inside the duct unit 700.

[0060] However, sirocco fans tend to produce particularly loud fan noise, which is an unpleasant noise for users. The causes of fan noise include aerodynamic noise generated by the rotation of the fins, airflow noise generated by turbulence in the airflow, and mechanical noise generated by the creaking of the bearings. As already mentioned, in order to reduce fan noise, it has been considered to quiet the airflow noise, and in fact, airflow noise is quieted using a side-branch type noise reduction device based on Helmholtz's principle. The quieting of airflow noise using a side-branch type noise reduction device will be explained using Figure 13.

[0061] As shown in Figure 13, in the side-branch type noise reduction device, a fan 2 is fixed to the end of a duct 1 attached to a housing (not shown). Furthermore, a side branch 4 is provided that protrudes from the side of the duct 1 in a direction intersecting the airflow direction, downstream of the airflow direction generated within the duct 1. In this case, the airflow noise generated by the fan 2 is divided into a first path from point A to point B and a second path from point A to point B via point C. The length L of the side branch 4 is set so that the phase of the waveforms of the sound passing through the first path (point A-point B) and the sound passing through the second path (point A-point C-point B) are shifted by 180°. Therefore, at point B, the sound that has passed through the first path and the sound that has passed through the second path interfere with each other, reducing the airflow noise.

[0062] However, recently there has been a demand for further miniaturization of the image forming apparatus 101, and the space available for installing fans and ducts is limited. For this reason, it is difficult to adopt a side-branch type noise reduction device as in the past. Specifically, the speed of sound in air is "approximately 331,000 mm / s," so if the frequency of the airflow sound is assumed to be "1,000 Hz," the distance λ that the airflow sound travels in one cycle is "331,000 / 1,000 = 331 mm." In this case, in order to reduce the airflow sound, it is necessary to install a duct 1 with side branches 4 of length L "2L = λ / 2, L = λ / 4 = 82.75 mm." However, recent image forming apparatuses 101 do not have enough space to install a duct 1 with side branches 4.

[0063] Therefore, in this embodiment, in order to reduce the airflow noise generated by the operation of the fan without using a duct with side branches, a duct configuration was adopted in which a part of the duct that constitutes the airflow path is a silent duct 710 described later. The silent duct 710 will be explained with reference to Figures 8 to 11. In the following, an example will be given in which the silent duct 710 is used in the duct located downstream of the image exhaust fan 410 in the airflow direction of the image airflow 401 in order to reduce the airflow noise generated by the operation of the image exhaust fan 410.

[0064] <Soundproof duct> The opening of the image-forming exhaust fan 410 is formed in a rectangular cross-section. Accordingly, as shown in Figure 8, the silent duct 710 has a main body 740 formed in a rectangular cross-section. The main body 740 has a duct inlet 720 through which air flows in as the image-forming exhaust fan 410 operates, and a duct outlet 721 through which the air that has flowed in from the duct inlet 720 flows out. The main body 740 forms an air passage that directs the air that has flowed in from the duct inlet 720 to the duct outlet 721.

[0065] In this embodiment, the main body 740 has two opposing wall surfaces 730 and 731, and two opposing wall surfaces 732 and 733 that extend in a direction perpendicular to the wall surfaces 730 and 731. As a result, the main body 740 has a roughly rectangular cross-section. The main body 740 is formed in a rectangular shape, with the width of the two wall surfaces 730 and 731, which are perpendicular to the rotation axis 410a of the image-forming exhaust fan 410, being wider than the width of the wall surfaces 732 and 733. Multiple sound-absorbing holes 711 are formed in the wider wall surfaces 730 and 731, serving as through holes that connect the inside and outside of the main body 740. In other words, the sound-dampening duct 710 has a wall surface 730 as a first perforated wall surface with a plurality of sound-absorbing holes 711 formed as first through-holes, and a wall surface 731 as a second perforated wall surface provided opposite the wall surface 730 and with a plurality of sound-absorbing holes 711 formed as second through-holes. The wall surface 730 and the wall surface 731 are two surfaces that form the longer side in a cross-section where the area is larger than that of the other wall surfaces 732 and 733.

[0066] Furthermore, sound-absorbing holes 711 may be formed on wall surfaces 732 and 733 of the wall surfaces 730 to 733, or sound-absorbing holes 711 may be formed on only one of the wall surfaces 730 to 733.

[0067] In this embodiment, when the airflow noise generated by the operation of the image-forming exhaust fan 410 passes through the sound-dampening duct 710, a portion of the airflow noise enters the sound-absorbing holes 711 and vibrates, converting a portion of the sound energy into thermal energy, thereby achieving a sound-dampening effect. The image-forming exhaust fan 410 is a sirocco fan that generates airflow by the rotation of its fins around the fan's rotation axis 410a. Therefore, by forming sound-absorbing holes 711 on the two wall surfaces 730 and 731 perpendicular to the fan's rotation axis 410a as described above, a high sound-dampening effect can be obtained. If sound-absorbing holes 711 are formed only on the other wall surfaces 732 and 733, the sound-dampening effect is relatively smaller compared to when sound-absorbing holes 711 are formed only on wall surfaces 730 and 731. However, if sufficient sound-absorbing holes 711 are not obtained by forming them only in the wall sections 730 and 731, sound-absorbing holes 711 may be formed in all four wall sections 730 to 733 to enhance the sound-absorbing effect.

[0068] However, if the sound-dampening duct 710 is to be manufactured using resin injection molding with a mold, a mold capable of forming sound-absorbing holes 711 on all four sides would be complex and costly. Therefore, it is conceivable to prepare separate molds to create divided parts of the sound-dampening duct 710 and then assemble them. However, in such a case, gaps tend to form between the divided parts, requiring additional materials to fill the gaps. Furthermore, steps will be created between the parts, increasing the airflow noise generated by the operation of the image-forming exhaust fan 410, so ultimately, even if sound-absorbing holes 711 are formed, sufficient sound-dampening effect cannot be obtained. For this reason, it is preferable to form sound-absorbing holes 711 only on the wall surfaces 730 and 731 perpendicular to the fan's rotation axis 410a, as much as possible.

[0069] In contrast, if the sound-absorbing duct 710 is made of metal, it is easier to form sound-absorbing holes 711 on all four sides, and the spacing between the sound-absorbing holes 711 can be narrower compared to when it is made of resin, which has the advantage of increasing the number of sound-absorbing holes 711. However, as will be described later, in order to reduce the cross-sectional area of ​​the air passage in the area where the sound-absorbing holes 711 are provided, it is more expensive to manufacture the sound-absorbing duct 710 with the downstream side of the duct inlet 720 formed in a sloping shape if it is made of metal than if it is made of resin. Considering these advantages and disadvantages, it is better to manufacture the sound-absorbing duct 710 from resin rather than metal.

[0070] Furthermore, if there is a step between the outlet 410b of the image-forming exhaust fan 410 shown in Figure 9 and the duct inlet 720 of the silent duct 710, a loud airflow noise will be generated. Therefore, it is desirable to have no step, but it is difficult to form the image-forming exhaust fan 410 and the silent duct 710, which are different components, so that they can be connected without a step. For this reason, in this embodiment, the duct inlet 720 is made slightly wider than the outlet 410b of the image-forming exhaust fan 410.

[0071] Furthermore, the shape of the sound-dampening duct 710 downstream of the duct inlet 720 in the airflow direction is preferably such that the airflow spreads within the sound-dampening duct 710 (inside the duct) and a portion of the airflow sound easily enters the sound-absorbing holes 711. In this embodiment, the downstream side of the duct inlet 720 is inclined so that the cross-sectional area of ​​the airflow path in the sound-absorbing hole region 725 where the sound-absorbing holes 711 are provided is smaller than the cross-sectional area of ​​the outlet 410b.

[0072] The main body 740 has a first main body 741 whose cross-sectional area narrows from upstream to downstream with respect to the airflow direction (arrow Y direction) and a second main body 742 which is formed continuously downstream of the first main body 741 and whose cross-sectional area widens from upstream to downstream. In the first main body 741, in order to narrow the duct cross-sectional area from the duct inlet 720 to the central part of the duct 723 at the boundary with the second main body 742 where the cross-sectional area is smallest 722, the wall surfaces 730 and 731 are inclined toward each other with a slope of about 1 degree. In the second main body 742, in order to widen the duct cross-sectional area from the central part of the duct 723 to the duct outlet 721, the wall surfaces 730 and 731 are inclined toward each other with a slope of about 1 degree. Thus, the sound-dampening duct 710 is formed such that, with respect to the airflow direction, the airflow path at the central part of the duct 723 is narrower than the airflow path at the upstream duct inlet 720. Furthermore, the sound-dampening duct 710 is formed such that, with respect to the airflow direction, the airflow path at the downstream duct outlet 721 is wider than the airflow path at the central part of the duct 723.

[0073] In this embodiment, the first main body portion 741 is tilted to allow some of the airflow sound to enter the sound-absorbing holes 711, as described above. On the other hand, the second main body portion 742 is tilted to widen the cross-sectional area of ​​the duct outlet 721. This is because if the cross-sectional area of ​​the duct outlet 721 is narrow, the airflow sound flowing out from the main body portion 740 tends to be louder, and this is to prevent that. In this embodiment, in the wall portions 730 and 731, sound-absorbing holes 711 are not formed in the central portion 723 of the duct.

[0074] It is preferable that the sound-absorbing holes 711 formed in the wall portion 730 and the sound-absorbing holes 711 formed in the wall portion 731 are formed in positions where they do not overlap when viewed from the wall portion 730 to the wall portion 731. By offsetting the sound-absorbing holes 711 in the wall portion 730 and the wall portion 731, a portion of the airflow sound in the sound-dampening duct 710 can more easily enter the sound-absorbing holes 711 in both the wall portion 730 and the wall portion 731, thereby further enhancing the sound-dampening effect of the airflow sound. It is preferable that the sound-absorbing holes 711 are round holes with a diameter of "3 mm or more and 12 mm or less". It is not necessary for all sound-absorbing holes 711 to have the same diameter, but in this embodiment, the diameter of all sound-absorbing holes 711 is set to "6.4 mm". It is also preferable that the sound-absorbing holes 711 are evenly distributed in the main body portion 740.

[0075] As shown in Figure 10, in wall sections 730 and 731, all of the sound-absorbing holes 711 are covered with sound-absorbing sheets 715, taking into consideration the leakage of airflow from the sound-silent duct 710. The sound-absorbing sheets 715, as sound-absorbing members, are arranged on the outer surfaces of wall sections 730 and 731, respectively. The sound-absorbing sheets 715 are formed in sheet form from sound-absorbing materials such as ethylene propylene diene rubber (EPDM) or urethane foam, or glass fiber glass wool or mineral rock wool.

[0076] Generally, a thicker sound-absorbing sheet 715 is preferable because it can adapt to a wider frequency range of sound and provide a better noise reduction effect. However, in this embodiment, to obtain a high effect at a low cost, a sound-absorbing sheet 715 made of EPDM foam with a thickness of "5 mm" was used. Note that when using an EPDM or urethane sound-absorbing sheet 715, if it is crushed, it becomes difficult to obtain a noise reduction effect. Therefore, when providing a cover or the like on the sound-reducing duct 710, it is necessary to avoid crushing the sound-absorbing sheet 715.

[0077] As described above, by covering the sound-absorbing holes 711 with the sound-absorbing sheet 715, some of the airflow sound that enters the sound-absorbing holes 711 enters the sound-absorbing sheet 715, and as the sound diffuses significantly within it, some of the sound energy is converted into heat energy, thus reducing the sound level.

[0078] As shown in Figure 11, the sound-absorbing sheet 715 is attached to the sound-dampening duct 710 with adhesive double-sided tape 716 as an adhesive material. However, if even a part of the sound-absorbing holes 711 is blocked by the double-sided tape 716, the sound-dampening effect of the sound-absorbing holes 711 will be reduced compared to when they are not blocked. Therefore, the double-sided tape 716 is used to adhere the sound-absorbing sheet 715 to the non-formed area 710a (the area indicated by the diagonal lines) where sound-absorbing holes 711 are not formed, in other words, outside the areas 710B and 710c where sound-absorbing holes 711 are formed.

[0079] However, if the double-sided tape 716 adheres the sound-absorbing sheet 715 only to a portion of the duct, such as the ends (720, 721), the airflow passing through the sound-absorbing holes 711 will cause the sound-absorbing sheet 715 to lift up, reducing its sound-dampening effect. Therefore, in addition to adhering the sound-absorbing sheet 715 to the duct ends (720, 721), the double-sided tape 716 also adheres the sound-absorbing sheet 715 to the central part of the duct 723.

[0080] Furthermore, it is preferable that the sound-absorbing holes 711 formed in the wall portions 730 and 731 be provided in proportion to a predetermined ratio or more of the surface area of ​​the sound-absorbing hole region 725 of the main body portion 740. Here, the sound-absorbing hole region 725 in this embodiment refers to the area shown by the line connecting the outlines of the multiple sound-absorbing holes 711, as shown in Figure 8. For example, it is desirable that the ratio of the area occupied by the sound-absorbing holes 711 to the area of ​​the sound-absorbing hole region 725 be "5% or more". However, considering the processability of the sound-absorbing holes 711 for the sound-dampening duct 710 and the ease of attaching the double-sided tape 716, it is more preferable that the ratio of the area occupied by the multiple sound-absorbing holes 711 to the surface area of ​​the sound-absorbing hole region 725 be "5% or more and 45% or less".

[0081] In this embodiment shown in Figure 8, the area occupied by the sound-absorbing holes 711 in the wall portion 730 is "27.8%" of the area of ​​the sound-absorbing hole region 725. In this embodiment, the case where sound-absorbing holes 711 are provided in the wall portions 730 and 731 is shown as an example, but even when sound-absorbing holes are provided in the other wall portions 732 and 733, it is desirable to provide them in the above proportion. Furthermore, the material of the sound-silent duct 710 is assumed to be resin, and the distance between the two sound-absorbing holes 711 provided in the wall portions 730 and 731 is limited from the viewpoint of the strength of the resin material, the strength of the mold used for molding, moldability, etc. Although it depends on the wall thickness of the sound-silent duct 710, the distance between the two sound-absorbing holes 711 should be at least 3 mm, and the desirable area proportion is calculated with the sound-absorbing hole diameter in the range of "3 mm to 12 mm". However, even if the area proportion falls outside the above range, the effect will be limited, but it will not be eliminated.

[0082] Figure 12 shows a comparison of the sound power level of the airflow noise when the image-forming exhaust fan 410 is operated independently, using the sound-dampening duct 710 with sound-absorbing holes 711 of this embodiment and the duct without sound-absorbing holes of the comparative example. As can be seen from Figure 12, the sound power level in the comparative example was "76.9 dB", and the sound power level in this embodiment was "71.2 dB". In other words, by using the sound-dampening duct 710 with sound-absorbing holes 711 of this embodiment, a noise reduction effect of "5.7 dB" was obtained. This indicates that the sound energy can be reduced by "73%", making the sound quieter.

[0083] For example, in noise reduction configurations that reduce noise by interfering with specific frequencies, such as side branches, while there is a high reduction effect for specific frequencies, there is a drawback in that there are always frequencies that resonate and become louder. In contrast, the noise reduction duct 710 of this embodiment does not have a resonant frequency and can reduce noise across a wide range of frequencies, thus achieving a higher noise reduction effect than noise reduction based on the Helmholtz principle. Furthermore, since there is no need to change the shape to match specific frequencies, even when changing to a fan with a higher rotation speed, or when a single fan is used while changing its rotation speed, one noise reduction duct 710 can be used without having to replace it with a noise reduction duct 710 of a different shape. Moreover, it is possible to use only the noise reduction duct 710 without having to replace it with a noise reduction duct 710 of a different shape, such as one with a different hole diameter.

[0084] As described above, in this embodiment, a sound-dampening duct 710 is used, in which a plurality of sound-absorbing holes 711 are formed as a duct, and these plurality of sound-absorbing holes 711 are covered with a sound-absorbing sheet 715, thereby achieving the effect of dampening airflow noise. That is, when a portion of the airflow noise generated in conjunction with the operation of the image-forming exhaust fan 410 passes through the sound-absorbing holes 711, a portion of the sound energy is converted into thermal energy, thereby dampening the airflow noise. Furthermore, a portion of the sound energy that has passed through the sound-absorbing holes 711 is further converted into thermal energy by the sound-absorbing sheet 715, resulting in even greater dampening of the airflow noise. In this way, the airflow dampened by the sound-dampening duct 710 is discharged from the duct outlet 721. Thus, according to this embodiment, it is possible to dampen the airflow noise generated in conjunction with the operation of the fan with a simple configuration, without using a plurality of ducts of different lengths or a duct with side branches, as in the conventional method. In addition, there is no need to secure a large space to interfere with specific frequencies with side branches, etc., and a large sound-dampening effect can be obtained in a small space, thus achieving space savings.

[0085] <Other Embodiments> Although a sirocco fan was used in this embodiment, the invention is not limited to this type of fan. Airflow noise can also be generated by other fans such as axial fans, so this embodiment can be applied without being limited to the type of fan.

[0086] Furthermore, the silent duct 710 described above is not limited to being used as a duct located downstream of the image exhaust fan 410 in the image creation airflow 401, but may also be used as a duct located upstream of the image exhaust fan 410 in the airflow direction. Moreover, the silent duct 710 is not limited to the image creation airflow 401, but may also be used in other airflows as described above (see Figure 3). [Explanation of symbols]

[0087] 101...Image forming apparatus, 401...Air blower (exhaust device, image forming airflow), 410...Fan (image forming exhaust fan), 412...Filter (image forming exhaust filter), 500...Image forming means (image forming transfer apparatus), 500A...Housing, 703...Another duct (image forming exhaust duct), 710...Duct (silent duct), 711...Through-hole (first through-hole, second through-hole, sound-absorbing hole), 715...Sound-absorbing material (sound-absorbing sheet), 716...Adhesive material (double-sided tape), 720...Inlet (duct inlet), 721...Outlet (duct outlet), 723...Boundary (center of duct), 730...Perforated wall section (first perforated wall section, wall section), 731...Perforated wall section (second perforated wall section, wall section), 740...Main body section, 741...First main body section, 742...Second main body section, S...Recording material

Claims

1. An image forming section for forming an image on a recording member; A fan that generates airflow; a duct having an inlet through which air flows in, an outlet through which the air flows out, and a cylindrical main body portion that forms an air passage through which the air flows from the inlet to the outlet; A perforated plate having a plurality of through holes formed therein, the perforated plate being disposed along at least a portion of the air passage; A sound-absorbing member having sound-absorbing properties is arranged on the outer surface of the perforated plate so as to cover the plurality of through holes.

1. An image forming apparatus comprising:

2. The perforated plate constitutes a part of the wall of the main body of the duct, 2. The image forming apparatus according to claim 1,

3. The ratio of the area occupied by the plurality of through holes to the surface area of ​​the region in which the plurality of through holes are formed in the hole plate is 5% or more and 45% or less; 3. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

4. The plurality of through holes include round holes having a hole diameter of 3 mm or more and 12 mm or less.

4. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. The perforated plate and the sound absorbing member are bonded with an adhesive member.

5. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

6. The duct is a first main body portion having a surface area through which the airflow passes that becomes smaller from upstream to downstream in an airflow direction, which is a direction in which the airflow flows; a second main body portion formed continuously on a downstream side of the first main body portion with respect to the air flow direction, the second main body portion having a surface area through which the air flow passes that becomes wider from the upstream side to the downstream side; 6. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

7. The perforated plate constitutes a part of a wall of the first body portion or a part of a wall of the second body portion, No through hole is formed at the boundary between the first body portion and the second body portion.

7. The image forming apparatus according to claim 6,

8. The duct, A first wall portion at least partially constituted by the perforated plate; a second wall portion opposed to the first wall portion, the plurality of through holes are a plurality of first through holes, A plurality of second through holes are formed in the second wall portion.

8. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

9. Each of the first through holes formed in the perforated plate does not overlap any of the second through holes when viewed in a line of sight along a direction in which the first wall portion and the second wall portion face each other.

9. The image forming apparatus according to claim 8,

10. The main body of the duct is composed of four sides that form a rectangular cross section, The first wall portion and the second wall portion are two of the four surfaces that form a long side in a cross section.

10. The image forming apparatus according to claim 8, wherein the first and second electrodes are arranged in a first direction.

11. The fan is connected to the inlet of the duct.

11. The image forming apparatus according to claim 1,

12. The fan is a sirocco fan.

12. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

13. The duct is a first duct, a second duct connected to the duct; a filter disposed between the first duct and the second duct.

13. The image forming apparatus according to claim 1, wherein the image forming apparatus is a multi-layered image forming apparatus.

14. The sound absorbing member is formed in a sheet shape from any one of ethylene propylene diene rubber or urethane foam, glass wool, and rock wool.

14. The image forming apparatus according to claim 1,

15. A fan that generates an airflow; a duct having an inlet through which air flows in, an outlet through which the air flows out, and a cylindrical main body portion that forms an air passage through which the air flows from the inlet to the outlet; A perforated plate having a plurality of through holes formed therein, the perforated plate being disposed along at least a portion of the air passage; A sound-absorbing member having sound-absorbing properties is arranged on the outer surface of the perforated plate so as to cover the plurality of through holes. A blower device characterized by:

Images