Image forming device

Abstract

To improve maintainability during filter replacement in an image forming apparatus having a plurality of housings.SOLUTION: In an image forming apparatus comprising a first housing having an image forming unit and a second housing having a fixing unit, an airflow taking in air in the vicinity of a conveying unit provided in the first housing and conveying a sheet to the fixing unit is merged with an airflow taking in air in the vicinity of the fixing unit provided in the second housing, and the merged airflows are exhausted to an outside of the image forming apparatus through one filter.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] In conventional image forming apparatuses, various units provided inside the apparatus, such as an imaging unit that forms a toner image, a fixing unit that heats the toner and fixes it to a sheet, and a power supply unit that supplies power to the entire apparatus, may generate heat as the apparatus operates. Therefore, a configuration is generally used in which a blower fan is provided to create an air flow, and the air drawn in from each unit is exhausted to the outside of the apparatus through an exhaust port, thereby dissipating the heat from each unit.

[0003] In this configuration, ozone, dust, volatile organic compounds (VOCs), ultrafine particles (UFPs), etc. may be generated near the image forming unit that forms the toner image and the fixing unit that heats the toner.

[0004] Therefore, Patent Document 1 discloses a configuration in which a collection filter is arranged in an air flow path for exhausting air drawn in from the image forming unit and the fixing unit, and the purified air is exhausted to the outside of the device through an exhaust port. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 7-271272 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, electrophotographic image forming apparatuses have spread from office use to commercial printing, and as a result of their increasing productivity, image quality, stability, lifespan, and functionality, the apparatuses have tended to become larger in size. As the apparatuses become larger, it becomes more difficult to transport them during manufacturing and indoor installation.

[0007] Therefore, in recent years, image forming devices for commercial printing have been proposed that consist of multiple housings, for example, a housing having a transfer unit that transfers a toner image onto a sheet, and a housing having a fixing unit that fixes the toner image transferred onto the sheet.

[0008] On the other hand, in the fixing portion, the above-mentioned VOCs, UFPs, etc. are known to accumulate upstream of the fixing nip of the fixing portion in the sheet conveying direction.

[0009] Therefore, if the fixing unit is located upstream of one of the multiple housings in the sheet transport direction, it is necessary to provide an air flow for capturing VOCs and UFPs in the housing located upstream of the housing in which the fixing unit is located.

[0010] As a result, in an image forming apparatus consisting of multiple housings, it was necessary to provide an air flow for each of the multiple housings to exhaust air near the fixing unit, which required a collection filter for each of the multiple air flows, which could reduce the efficiency of maintenance such as filter replacement.

[0011] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an image forming apparatus having a plurality of housings, which can improve the ease of maintenance when replacing filters. [Means for solving the problem]

[0012] An image forming apparatus according to one aspect of the present invention comprises: an image forming apparatus having a first housing having an imaging unit therein that forms a toner image on a sheet; and a second housing having a fixing unit that fixes the toner image formed by the imaging unit onto the sheet, the second housing being provided downstream of the first housing in a sheet conveying direction, the image forming apparatus comprising: a conveyor belt provided in the first housing that conveys the sheet on which the toner image has been formed by the imaging unit to the fixing unit; a first intake fan that draws in air so that the sheet adheres to an outer circumferential surface of the conveyor belt; a first duct unit provided in the first housing that forms an air path through which the air drawn in by the first intake fan passes; a second intake fan provided in the second housing for drawing in air near the fixing unit; a second duct unit provided in the second housing for forming an air path through which air flowing in from the first duct unit and air drawn in by the second intake fan pass, the second duct unit having an exhaust port for discharging air to the outside of the image forming apparatus and a filter through which the air exhausted from the exhaust port passes; another conveyor belt provided downstream of the conveyor belt in the sheet conveying direction and having a plurality of intake ports; and another intake fan provided on the inner periphery of the other conveyor belt for drawing in air so that the sheet is attracted to the outer periphery of the other conveyor belt. An image forming apparatus comprising: [Effects of the Invention]

[0013] According to the present invention, in an image forming apparatus having a plurality of housings, it is possible to improve the ease of maintenance when replacing filters. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming system including an image forming apparatus. [Figure 2] FIG. 2 is a schematic cross-sectional view of an image forming unit of the image forming apparatus. [Figure 3] FIG. 2 is a schematic cross-sectional view of a fixing and conveying unit of the image forming apparatus. [Figure 4] FIG. 2 is a rear view of the airflow arrangement of the image forming apparatus. [Figure 5] FIG. 3 is a block diagram of a fan airflow rate of the image forming apparatus. [Figure 6] FIG. 4 is a diagram illustrating a duct unit showing a pre-fixing transport air flow. [Figure 7] FIG. 10 is a perspective view of the pre-fixing transport air flow as viewed from the rear side. [Figure 8] FIG. 10 is a diagram illustrating the joints between the first pre-fixed suction duct unit, the second pre-fixed suction duct unit, and the pre-fixed exhaust duct unit. [Figure 9] FIG. 3 is a rear view of the fixing exhaust duct unit. [Figure 10] FIG. 10 is a diagram illustrating a duct unit showing a pre-fixing transport air flow in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described in the following embodiments may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and are not intended to limit the scope of the present invention to those alone.

[0016] First Embodiment (Image forming system) FIG. 1 is a schematic cross-sectional view of an image forming system 100 including an image forming apparatus 101 according to an embodiment of the present invention. The image forming apparatus 101 shown in FIG. 1 is composed of an image forming unit 102 that transfers a toner image onto a fed sheet S, and a fixing and conveying unit 103 that fixes the transferred toner image onto the sheet S. The image forming unit 102 and the fixing and conveying unit 103 are each independent housings, and are movable by means of multiple casters provided on each. This configuration makes it possible to package and transport even large devices in separate housings, improving the workability during logistics up to installation.

[0017] An original reading device 104 for reading an original image and an original feeding device 105 for feeding a plurality of stacked originals to the original reading device 104 one by one are selectively connected to the upper part of the image forming unit 102 .

[0018] Any one of a large-capacity feeding device 106 having a plurality of sheet storage units, a manual feeding device (not shown), or a long sheet feeding device (not shown) capable of accommodating long sheets can be selectively connected to the upstream side in the sheet conveying direction of the image forming unit 102. Any one of a large-capacity feeding device, a manual feeding device, and a long sheet feeding device (not shown) can be selectively connected in series further upstream of the large-capacity feeding device 106.

[0019] A sensing device 107 is selectively connected downstream in the sheet conveying direction of the fixing conveying section 103 to read the fixed toner image formed on one or both sides of the sheet S, detect image density and image position deviation, and perform feedback correction on the image signal transmitted to the image forming section 102.

[0020] Further downstream of the fixing conveying section 103 or the sensing device 107, various sheet processing devices (not shown), such as an inserter, puncher, case binder, large-capacity stacker, folder, finisher, trimmer, etc., can be selectively connected, either individually or in combination.

[0021] As described above, the image forming apparatus 101 of this embodiment can be selectively connected to a variety of optional devices upstream and downstream in the sheet conveyance direction, thereby enabling in-line output of products that have undergone a variety of post-processing processes on a variety of materials, thereby providing an image forming system 100 that is highly productive, has high image quality, is highly stable, and is highly functional. Note that in this embodiment, the arrow X direction shown in the drawing is the width direction (left-right direction) of the image forming system 100, the arrow Y direction is the front-rear direction, and the arrow Z direction is the vertical direction (up-down direction).

[0022] (Image forming apparatus: image forming unit 102) FIG. 2 is a schematic cross-sectional view of the image forming unit 102 in the image forming apparatus 101 of this embodiment. The image forming unit 102 shown in FIG. 2 includes a plurality of image forming stations 200 that form different toner images for each of the colors yellow (Y), magenta (M), cyan (C), and black (K). FIG. 2(a) is a schematic cross-sectional view of the entire image forming unit 102. FIG. 2(b) is a schematic cross-sectional view of the image forming stations 200Y, 200M, and 200C. FIG. 2(c) is a schematic cross-sectional view of the image forming station 200K.

[0023] As shown in Figure 2(a), the surface of the photosensitive drum 201 in each image forming station 200 is uniformly charged by a primary charger 202, and then an electrostatic latent image is formed by a laser scanner 203 driven based on transmitted image information signals. The latent image formed here is developed into a toner image by a developing device 204. In this embodiment, the photosensitive drum 201 is an example of a photosensitive member, the laser scanner 203 is an example of an exposure unit, and the developing device 204 is an example of a developing unit.

[0024] The toner consumed during development is replenished appropriately to each developing device 204 from a toner bottle 205 via a toner replenishment path 206. The imaging stations 200Y, M, and C all have a common configuration, except for the color of toner they use. In the following description, the reference symbols Y, M, C, and K will be omitted for the common configuration. Note that the imaging station 200K has a configuration with some functions that differ from those of the imaging stations 200Y, M, and C, and the differences will be described later.

[0025] The toner image on the photosensitive drum 201 is sequentially transferred onto the intermediate transfer belt 208 by the primary transfer roller 207, with a predetermined pressure and an electrostatic load bias applied. Here, the image forming station 200 and the intermediate transfer belt 208 in this embodiment are an example of an image forming unit. A small amount of residual toner remaining on the photosensitive drum 201 after transfer is removed by a photosensitive drum cleaner 209 in preparation for the next image formation. The removed residual toner is collected in a recovered toner container 211 via a toner recovery path 210. Here, the photosensitive drum cleaner 209 is an example of a cleaning unit for cleaning the residual toner on the photosensitive drum 201, and the recovered toner container 211 is an example of a recovery unit.

[0026] Meanwhile, sheets S fed one by one from a sheet storage unit 212 inside the image forming unit 102 or from any of the sheet feeders connected externally to the image forming apparatus 101 are subjected to skew correction by forming a loop by making the leading edge follow the nip portion of the registration rollers 213. Thereafter, the registration rollers 213 convey the sheet S to the secondary transfer unit in synchronization with the toner image on the intermediate transfer belt 208.

[0027] The toner image on the intermediate transfer belt 208 is transferred to the sheet S by applying a predetermined pressure and electrostatic load bias at a secondary transfer nip consisting of an inner secondary transfer roller 214 and an outer secondary transfer roller 215. After transfer, the small amount of residual toner remaining on the intermediate transfer belt 208 is removed by an intermediate transfer belt cleaner 216 to prepare for the next image formation. The removed residual toner is collected in a recovered toner container 211 via a toner recovery path 210. The sheet S onto which the toner image has been transferred is transported downstream to the fixing and transport section 103 by pre-fixing transport belts 217a and 217b.

[0028] (Image forming device: black and white image formation) The image forming apparatus 101 of this embodiment can form full-color images using all of the Y, M, C, and K image forming stations 200 described above, as well as black-and-white images using only the K image forming station 200K.

[0029] During black-and-white image formation, the primary transfer roller 207, primary transfer auxiliary roller 218, and intermediate transfer belt 208 are displaced to the positions indicated by the dashed lines in Figure 2(a) by a spacing mechanism (not shown). This spacing mechanism allows the Y, M, and C image forming stations 200Y, 200M, and 750, which are spaced from the intermediate transfer belt 208, to stop rotating. This means that unnecessary wear on parts due to unnecessary rotation can be prevented in the Y, M, and C image forming stations 200Y, 200M, and 750, thereby extending their lifespan.

[0030] On the other hand, photosensitive drum 201K has a larger diameter suitable for a longer life than photosensitive drums 201Y, 201M, and 201C. Also, as shown in FIG. 2C, primary charger 202K is a non-contact type using a corona charger suitable for a longer life than the contact type using roller chargers of primary chargers 202Y, 202M, and 202C. Furthermore, toner bottle 205K has a larger capacity suitable for a longer life than toner bottles 205Y, 205M, and 205C.

[0031] With the above configuration, even for users who frequently use black and white image formation, the maintenance interval for the frequently used K imaging station 200K can be prevented from becoming shorter than that for the less frequently used Y, M, and C imaging stations 200Y, 200M, and 750.

[0032] Furthermore, the large diameter drum configuration using corona charger 202K has a wider charging width and is more suitable for high speeds than the small diameter drum configuration using roller chargers 202Y, 202M, and 202C, and therefore can also improve productivity when forming black and white images.

[0033] In the image forming unit 102, in which the conditions differ among the image forming stations 200, differences in shape and wear may cause differences in the amount of toner charge on the photosensitive drum 201. If differences in the amount of toner charge occur, the toner image may not be transferred uniformly to the sheet S in the secondary transfer process, resulting in a defective image. Therefore, the K photosensitive drum 201K is provided with a pre-transfer charger 219, which is a corona charger for equalizing the amount of toner charge on the Y, M, and C photosensitive drums 201Y, 201M, and 201C. Here, the pre-transfer charger 219 is an example of another charging unit provided between the developer 204K and the photosensitive drum cleaner 209K in the rotational direction of the photosensitive drum 201.

[0034] As described above, the configuration of this embodiment can provide an image forming apparatus 101 that is excellent in terms of high productivity, high image quality, high stability, and long life, not only in full-color image formation but also in black-and-white image formation.

[0035] (Image forming apparatus: fixing conveyance unit 103) 3 is a schematic cross-sectional view of the fixing and conveying section 103 in the image forming apparatus 101 of this embodiment. The fixing unit 301 shown in FIG. 3 fixes the toner image on the sheet S conveyed from the image forming section 102 onto the sheet S by applying heat and pressure.

[0036] In this embodiment, the fixing unit 301 has a heating roller 301a, which is heated by a heater (not shown), on its vertically upper side, and a pressure roller 301b, which presses the sheet against the heating roller 301a, on its vertically lower side. The toner image is fixed to the sheet S by heating and pressing it in the fixing nip formed by the heating roller 301a and the pressure roller 301b. The heating roller 301a and the pressure roller 301b then nip and convey the sheet downstream in the sheet conveyance direction while heating and pressurizing the sheet. Here, the fixing unit 301 is described as being made up of a pair of rollers, but the fixing unit 301 may also be made up of a conveyor belt that forms the fixing nip.

[0037] The sheet S heated by the fixing unit 301 is transported by the transport belts 302a, b while being cooled by the heat absorption of the heat sink 303 that contacts the inner surface of the transport belt 30a of the cooling unit 302, and is discharged via the discharge transport path 304 to the aforementioned sensing device 107 or a post-processing device not shown.

[0038] When the sheet S is to be discharged upside down, the sheet discharge reversal unit 305 performs switchback conveyance, swaps the leading and trailing ends of the sheet S, and discharges the sheet S upside down via the sheet discharge conveyance path 304 .

[0039] When forming images on both sides of the sheet S, the sheet S on which the image on the first side has been formed is switched back and conveyed in a duplex inversion unit 306, and the leading and trailing ends of the sheet S are swapped and conveyed upside down to a duplex conveyance path 307. Thereafter, the sheet S is rejoined by the registration rollers 213 in time with the subsequent sheet S fed from the sheet storage unit 212 inside the image forming unit 102 or from any of the aforementioned externally connected sheet feeding devices, and an image is formed on the second side in the same process as on the first side, and the sheet is discharged via a discharge conveyance path 304.

[0040] (Image forming device: Air flow arrangement) 4 is a diagram showing the airflow arrangement in the image forming apparatus 101 of this embodiment, as viewed from the rear side of the image forming apparatus 101. Here, the front side of the image forming apparatus 101 refers to the side from which the sheet storage unit 212 is pulled out relative to the image forming apparatus 101 when refilling sheets in the sheet storage unit 212, and is the position where a user who operates the image forming apparatus 101 stands. The rear side of the image forming apparatus 101 refers to the side opposite the front side in the front-to-rear direction (the insertion / removal direction of the sheet storage unit 212).

[0041] 4, the image forming apparatus 101 includes an imaging airflow 401, a pre-fixing transport airflow 402, and a power supply airflow 403. The fixing transport section 103 includes a fixing airflow 404, a cooling unit airflow 405, a power supply airflow 406, and an electrical equipment airflow 407.

[0042] The imaging air flow 401 of the image forming unit 102 includes a primary charger intake fan 408, developing unit intake fans 409Y, 409M, and 409C, and an imaging exhaust fan 410.

[0043] The primary charger intake fan 408 supplies outside air for ventilation to the primary charger 202K of the image forming station 200K. A primary charger intake filter 411 is disposed upstream of the primary charger intake fan 408 to collect dust floating in the outside air and supply purified air to the K primary charger 202K.

[0044] The developing unit intake fans 409Y, 409M, and 409C supply outside air to the developing units 204Y, 204M, and 204C for cooling.

[0045] The imaging exhaust fan 410 exhausts ozone emitted by the K primary charger 202K and the pre-transfer charger 219 due to corona discharge from the K imaging station 200K. The imaging exhaust fan 410 also exhausts heat emitted by each developing device 204 due to friction during rotation from each imaging station 200. The imaging exhaust fan 410 also exhausts heat accumulated inside through the toner recovery path 210. Furthermore, the imaging exhaust fan 410 exhausts minute amounts of floating toner emitted in each process of toner image formation from each imaging station 200. An imaging exhaust filter 412 is disposed upstream of the imaging exhaust fan 410 to collect ozone and toner-containing dust exhausted from each imaging station 200 and exhaust the purified air to the outside of the device 101.

[0046] According to the configuration of the imaging air flow 401 described above, the ozone, heat, and dust emitted during the imaging process can be efficiently exhausted without being retained in each imaging station 200, and can be collected by the imaging exhaust filter 412.

[0047] That is, it is possible to prevent charging image defects such as uneven charging caused by ozone or dust adhering to the photosensitive drum 201 or the primary charger 202, developed image defects caused by the toner overheating and its fluidity being reduced, operational malfunctions such as clogging of the toner transport path, and transferred image defects caused by ozone or dust adhering to the pre-transfer charger 219.

[0048] Therefore, it is possible to provide an image forming apparatus 101 that is excellent in high image quality, high stability, and long life. Also, it is possible to provide an image forming apparatus 101 that is excellent in environmental friendliness by reducing the amount of ozone and dust emitted to the outside of the image forming apparatus 101.

[0049] Furthermore, a pre-fixing conveying intake fan 413 is provided on the inner periphery of the pre-fixing conveying belts 217a, b to attract the sheet S to the outer periphery of the pre-fixing conveying belts 217a, b through suction ports (not shown) provided in the pre-fixing conveying belts 217a, b. In this embodiment, the pre-fixing conveying belts 217a, b are an example of a conveying unit, and the pre-fixing conveying intake fan 413 is an example of a first intake fan.

[0050] A total of four pre-fixing conveyance intake fans 413 are provided, two at the front and two at the rear of each of the fixing conveyance belts 217a and 217b. In this manner, the pre-fixing conveyance intake fans 413 form a pre-fixing conveyance air flow 402 of the image forming unit 102.

[0051] The pre-fixing conveying intake fan 413 is adjusted by a control circuit (not shown) to an optimum air volume depending on the material and shape of the conveyed sheet S. This configuration allows stable conveyance of a variety of materials without disturbing the unfixed toner image on the sheet S. Therefore, it is possible to provide an image forming apparatus 101 that is excellent in high image quality, stability, and functionality.

[0052] Note that pre-fixing conveyance intake fan 413 may suck in heat, VOCs, dust, and UFPs emitted by the adjacent fixing unit 301. Therefore, pre-fixing conveyance air flow 402 collects VOCs, dust, and UFPs using a lower fixing exhaust filter 422 (described later) and exhausts the purified air to the outside of apparatus 101. With this configuration, it is possible to provide an environmentally friendly image forming apparatus 101 that reduces the amount of VOCs, dust, and UFPs emitted to the outside of apparatus 101.

[0053] The power supply airflow 403 of the image forming unit 102 is equipped with a power supply exhaust fan 415 that exhausts heat emitted from the power supply board 414 to the outside of the image forming apparatus 101. As the power supply exhaust fan 415 exhausts heat, outside air for cooling is supplied from the power supply air intake 416, allowing the power supply board 424 to be efficiently cooled. This configuration makes it possible to prevent malfunctions and breakdowns of the image forming apparatus 101 that would otherwise occur due to a drop in output caused by an overheating of the power supply board 414. Therefore, it is possible to provide an image forming apparatus 101 that excels in high productivity, high stability, and long life.

[0054] The fixing air flow 404 of the fixing conveying unit 103 includes a fixing heat exhaust fan 417, a fixing pressurized air intake fan 418, a fixing pressurized air exhaust fan 419, and a moisture exhaust fan 420. In this embodiment, the fixing pressurized air exhaust fan 419 and the moisture exhaust fan 420 are examples of second air intake fans.

[0055] Fixing heat exhaust fan 417 mainly exhausts heat emitted from the upper part, which is the heated side, of fixing unit 301 to the outside of device 101. When the components that make up fixing unit 301 or the release agent (wax) contained in toner are heated, VOCs, dust, UFPs, etc. may be emitted along with the heat. Therefore, fixing upper exhaust filter 421 is provided downstream of the airflow generated by fixing heat exhaust fan 417 to capture VOCs, dust, and UFPs.

[0056] The fixing pressure intake fan 418 supplies outside air for cooling to the lower part, which is the pressure side, of the fixing unit 301. The fixing pressure exhaust fan 419 exhausts heat emitted from the lower part, which is the pressure side, of the fixing unit 301 to the outside of the image forming apparatus 101. The moisture exhaust fan 420 exhausts water vapor emitted from the sheet S heated by the fixing unit 301 to the outside of the apparatus 101.

[0057] A fixing lower exhaust filter 422 is disposed downstream of the airflow generated by the fixing pressurization exhaust fan 419, the moisture exhaust fan 420, and the pre-fixing transport intake fan 413 described above, in order to capture VOCs, dust, and UFPs that are released along with heat and water vapor.

[0058] The above-described configuration of fixing air flow 404 makes it possible to efficiently discharge the heat, moisture, VOCs, dust, and UFPs that are released during the heating process without allowing them to accumulate inside image forming apparatus 101. In other words, it is possible to prevent image defects and operational malfunctions that would otherwise be caused by heat accumulating in image forming apparatus 101 and causing toner and components of each unit to overheat.

[0059] Furthermore, excessive temperature rise on the pressure side of the fixing unit 301 can prevent poor fixed images and sheet transport problems, such as poor fixation and separation, caused by excessive heat applied to the toner during the fixing process. Condensation on the transport guide due to water vapor adhering, and transport problems and poor images caused by condensed water droplets adhering to the sheet S during transport, can also be prevented. Furthermore, malfunctions and sheet transport problems caused by the release agent (wax) vaporized by heating re-solidifying and adhering to components, etc., can be prevented. Therefore, an image forming apparatus 101 with excellent high image quality, high stability, and long life can be provided. Furthermore, an image forming apparatus 101 with excellent environmental friendliness can be provided, with reduced emissions of VOCs, dust, and UFPs to the outside of the image forming apparatus 101.

[0060] The cooling unit airflow 405 of the fixing and conveying section 103 includes a cooling unit exhaust fan 423 for discharging heat emitted by the heat sink 303 disposed inside the cooling unit 302 to the outside of the apparatus 101. The heat sink 303 of the cooling unit 302 is a heat exchanger that absorbs heat from the fixed sheet S via the conveying belt 302a and emits the absorbed heat. With this configuration, the sheet S heated by the fixing unit 301 can be efficiently cooled, and the amount of heat emitted from the sheet S in the downstream conveying path can be reduced.

[0061] That is, it is possible to prevent image defects and malfunctions caused by the toner in the image forming unit 102 overheating due to heat radiation from the sheet S during double-sided image formation. It is also possible to prevent toner images from sticking between sheets S when a large amount of finished products are stacked in the post-processing device. Therefore, it is possible to provide an image forming apparatus 101 that is excellent in high image quality and high stability.

[0062] The power supply airflow 406 of the fixing and conveying unit 103 includes power supply exhaust fans 425 and 426 that exhaust heat emitted from the power supply board 424 to the outside. As the power supply exhaust fans 425 and 426 exhaust air, cooling air is supplied from the power supply air intake 427, allowing the power supply board 424 to be efficiently cooled. This configuration makes it possible to prevent malfunctions and breakdowns caused by a drop in output due to an overheating of the power supply board 424. Therefore, it is possible to provide an image forming apparatus 101 that excels in high productivity and high stability.

[0063] The electrical airflow 407 of the fixing and conveying section 103 is equipped with an electrical exhaust fan 430 that exhausts heat emitted by electrical circuit boards 428 and 429 to the outside. As air is exhausted by the electrical exhaust fan 430, cooling air is supplied from an electrical intake port 431, allowing the electrical circuit boards 428 and 429 to be efficiently cooled. This configuration makes it possible to prevent malfunctions and breakdowns caused by a drop in output due to an overheating of the electrical circuit boards 428 and 429. Therefore, it is possible to provide an image forming apparatus 101 that excels in high productivity and high stability.

[0064] (Image forming equipment: Air flow balance) 5 is a block diagram showing the airflow rates of the intake and exhaust fans in the image forming apparatus 101 of this embodiment, where (a) shows the airflow rate of each fan in the image forming unit 102, and (b) shows the airflow rate of each fan in the fixing and conveying unit 103. The numerical values ​​shown in FIG. 5 indicate, as an example, the airflow rates of each fan when forming an image on cardboard.

[0065] The dashed lines in Figure 5(a) indicate the total range of the intake fan total air volume Q1 and the exhaust fan total air volume Q2 acting inside the image forming unit 102 of the image forming apparatus 101. Here, the power supply air flow 403 is configured with an independent air path that does not communicate with the inside of the image forming unit 102 or the fixing / conveying unit 103, and is configured to directly intake and exhaust outside air. Therefore, the power supply air flow 403 does not affect the air flow inside the image forming unit 102, and is therefore excluded from the total value. Here, the intake fans are fans that take in air from outside the image forming apparatus 101 into the inside of the apparatus, and among the fans provided in the image forming unit 102, the primary charger intake fan 408 and the three developer intake fans 409C, M, and Y correspond to this. An exhaust fan is a fan for discharging air inside the image forming apparatus 101 to the outside of the apparatus, and among the fans provided in the image forming unit 102, the image forming exhaust fan 410 and the four pre-fixing transport intake fans 413 are examples of this.

[0066] In this embodiment, the image forming apparatus 101 is configured such that the total air volume Q2 of the exhaust fans is larger than the total air volume Q1 of the intake fans of the image forming unit 102 as follows.

[0067] Q1:0.60m 3 / min <Q2:2.13m 3 / min With this configuration, the inside of the image forming unit 102 can be maintained at a negative pressure relative to the outside air. This prevents ozone and dust inside the image forming unit 102 from leaking out of the image forming apparatus 101 through tiny gaps such as the seams of the exterior cover. That is, the imaging exhaust filter 412 provided at the airflow exhaust port of the image forming unit 102 reliably captures ozone and dust inside the image forming apparatus 101, making it possible to provide an image forming apparatus 101 that is highly environmentally friendly.

[0068] The dashed line in Figure 5(b) indicates the total range of the total air volume Q3 of the intake fans and the total air volume Q4 of the exhaust fans acting inside the fixing and conveying section 103 of the image forming apparatus 101. Here, the intake fans are fans that take in air outside the image forming apparatus 101 into the inside of the apparatus, and among the fans provided in the fixing and conveying section 103, the fixing and pressurizing intake fan 418 corresponds to this. Furthermore, the exhaust fans are fans that exhaust air inside the image forming apparatus 101 to the outside of the apparatus, and among the fans provided in the fixing and conveying section 103, the three fixing and heat exhaust fans 417, the fixing and pressurizing exhaust fan 419, the humidity exhaust fan 420, the cooling unit exhaust fan 423, the power supply exhaust fans 425 and 426, and the electrical equipment exhaust fan 430 correspond to this.

[0069] In this embodiment, the total airflow rate Q4 of the exhaust fans is set to be greater than the total airflow rate Q3 of the intake fans.

[0070] Q3: 1.74m 3 / min <Q4:9.77m 3 / min This configuration makes it possible to maintain a negative pressure inside the fixing and conveying section 103 relative to the outside air. This prevents VOCs, dust, and UFPs inside the fixing and conveying section 103 from leaking to the outside of the image forming apparatus 101 through tiny gaps such as the seams of the exterior cover. That is, the upper fixing exhaust filter 421 and the lower fixing exhaust filter 422, which are provided upstream of the airflow with respect to the airflow exhaust port of the fixing and conveying section 103, reliably capture VOCs, dust, and UFPs inside the image forming apparatus 101, making it possible to provide an image forming apparatus 101 that is highly environmentally friendly.

[0071] Furthermore, in this embodiment, the differential air volume between the total air volume Q4 of the exhaust fans and the total air volume Q3 of the intake fans in the fixing conveying unit 103 is configured to be larger than the differential air volume between the total air volume Q2 of the exhaust fans and the total air volume Q1 of the intake fans in the image forming unit 102.

[0072] (Q2-Q1): 1.53m 3 / min<(Q4-Q3):8.03m3 / min With this configuration, the inside of the fixing and conveying section 103 can be kept at a relatively more negative pressure than the inside of the image forming section 102. Therefore, it is possible to prevent the heat, VOCs, dust, UFPs, and water vapor emitted inside the fixing and conveying section 103 from flowing into the inside of the image forming section 102 through the communication section between the image forming section 102 and the fixing and conveying section 103. In other words, it is possible to prevent the heat, VOCs, dust, UFPs, and water vapor that are likely to be generated near the fixing unit 301 from flowing into the inside of the housing of the image forming section 102 that is arranged adjacent to the fixing and conveying section 103.

[0073] This prevents image defects and operational malfunctions caused by heat from the fixing unit 301 flowing into the image forming section 102 and deteriorating the fluidity of the toner, image defects, transport defects and operational malfunctions caused by VOCs, dust or UFPs flowing in and adhering to components, and image defects and transport defects caused by water vapor flowing in and condensing on components.

[0074] As a result of the above, heat released inside the fixing and conveying section 103 is efficiently discharged from the air flow exhaust port of the fixing and conveying section 103 without accumulating inside the image forming section 102, and VOCs, dust, and UFPs are reliably captured by the upper fixing exhaust filter 421 and the lower fixing exhaust filter 422 provided at the exhaust port, making it possible to provide an image forming apparatus 101 that excels in high image quality, high stability, long life, and is environmentally friendly.

[0075] (Image forming unit 102: Pre-fixing transport air flow 402) Next, the pre-fixing transport air flow 402 of the image forming unit 102 in this embodiment will be described with reference to FIGS.

[0076] Fig. 6 is a cross-sectional view illustrating a duct unit that forms pre-fixing transport airflow 402. Fig. 7 is a perspective view showing a duct unit that forms pre-fixing transport airflow 402. Fig. 8 is a diagram showing the joints between first pre-fixing suction duct unit 431, second pre-fixing suction duct unit 432, and pre-fixing exhaust duct unit.

[0077] Pre-fixing transport airflow 402 is formed by a pre-fixing exhaust duct unit 430 and a fixing exhaust duct unit 442. Here, pre-fixing exhaust duct unit 430 has a first pre-fixing suction duct unit 431, a second pre-fixing suction duct unit 432, and an exhaust duct unit 440. In this embodiment, pre-fixing exhaust duct unit 430 is an example of a first duct unit that forms an air passage, and fixing exhaust duct unit 442 is an example of a second duct unit that forms an air passage.

[0078] The first pre-fixing suction duct unit 431 is provided with pre-fixing transport intake fans 413a and 413b that draw air into the duct unit, and the second pre-fixing suction duct unit 432 is provided with pre-fixing transport intake fans 413c and 413d that draw air into the duct unit.

[0079] As described above, these pre-fixing conveyance intake fans 413a-d are provided on the inner periphery of the pre-fixing conveyance belts 217a-b and are fans that suck air through suction ports (not shown) provided in the pre-fixing conveyance belts 217a-b so that the sheet S adheres to the outer periphery of the pre-fixing conveyance belts 217a-b. Here, the pre-fixing conveyance intake fans 413a-b are provided on the inner periphery of the pre-fixing conveyance belt 217a, and the pre-fixing conveyance intake fans 413c-d are provided on the inner periphery of the pre-fixing conveyance belt 217b. Note that as long as a sheet having unfixed toner thereon can be attracted to and conveyed by the pre-fixing conveyance belts 217a-b, the pre-fixing conveyance intake fans 413a-c do not necessarily have to be provided on the inner periphery of each belt. For example, the pre-fixing conveyance intake fans 413a-c may be provided outside the pre-fixing conveyance belts 217a-b inside the first and second pre-fixing suction duct units 431-432, and only the intake ports may be provided on the inner periphery of the pre-fixing conveyance belts 217a-b. In this embodiment, the pre-fixing conveyance intake fans 413a-d are an example of an intake fan, the pre-fixing conveyance intake fans 413a-b are an example of a first intake fan, and the pre-fixing conveyance intake fans 413c-d are an example of another intake fan. Furthermore, the pre-fixing conveyance belt 217a is an example of a conveyance belt, and the pre-fixing conveyance belt 217b is an example of another conveyance belt.

[0080] The air drawn by pre-fixing conveyance intake fan 413a passes through first upstream section 435aa, and the air drawn by pre-fixing conveyance intake fan 413b passes through second upstream section 435ab. Here, first upstream section 435aa and second upstream section 435ab are integrally formed of resin as first upstream duct 435a, and the air flows flowing through first upstream section 435aa and second upstream section 435ab are joined by first junction section 433.

[0081] Furthermore, the air drawn by pre-fixing transfer intake fan 413c passes through third upstream section 436aa, and the air drawn by pre-fixing transfer intake fan 413d passes through fourth upstream section 436ab. Here, third upstream section 436aa and fourth upstream section 436ab are integrally formed of resin as second upstream duct 436a, and the air flows flowing through third upstream section 436aa and fourth upstream section 436ab are joined by second junction section 434.

[0082] The first upstream duct 435a is connected to the first downstream duct 435b downstream of the first junction 433. A sealing sheet 445 is provided between the first upstream duct 435a and the first downstream duct 435b to prevent air leakage at the connecting portion. In addition, in the first upstream duct 435a, the airflow flowing through the first upstream portion 435aa and the airflow flowing through the second upstream portion 435ab are combined into a single airflow at the first junction 433 before being introduced into the first downstream duct 435b. This reduces the number of duct joints between the first upstream duct 435a and the first downstream duct 435b, thereby suppressing air leakage through the joints.

[0083] The second upstream duct 436a is connected to the second downstream duct 436b downstream of the second junction 434. A sealing sheet 447 is provided between the second upstream duct 436a and the second downstream duct 436b to prevent air leakage at the connecting portion. In the second upstream duct 436a, the airflows flowing through the third upstream portion 436aa and the fourth upstream portion 436ab are combined into a single airflow at the second junction 434 before being introduced into the second downstream duct 436b. This reduces the number of duct joints between the second upstream duct 436a and the second downstream duct 436b, thereby suppressing air leakage through the joints.

[0084] The airflow passing through the first downstream duct 435b is led to the first pre-exhaust duct 453 provided further downstream, and the airflow passing through the second downstream duct 436b is led to the second pre-exhaust duct 454.

[0085] Here, the first pre-fixed exhaust duct 453 and the second pre-fixed exhaust duct 454 are part of the exhaust duct unit 440, and are ducts for guiding air to a fixing exhaust duct unit 442 provided in the fixing conveying section 103 of the image forming apparatus 101. For this reason, the exhaust duct unit 440 includes a partition wall 458 for separating the first pre-fixed exhaust duct 453 and the second pre-fixed exhaust duct 454.

[0086] The first front exhaust duct 453, the second front exhaust duct 454 and the partition wall 458 are integrally formed of resin as an exhaust duct unit 440.

[0087] Here, the above-described pre-fixing conveying belt 217a is configured to be able to be pulled out from the image forming unit 102 toward the front side (arrow Y direction) of the image forming apparatus 101 when removing a sheet S if a conveyance abnormality (so-called JAM) occurs, or when performing unit maintenance. Therefore, a first pre-fixing suction duct unit 431 provided inside the pre-fixing conveying belt 217a is also configured to be able to be pulled out in the arrow Y direction.

[0088] Therefore, to prevent damage to each duct unit when a unit is inserted or removed with great force during maintenance, a front exhaust duct support plate 443 is provided between the first front suction duct unit 431 and the first front exhaust duct 453. This front exhaust duct support plate 443 prevents direct interference between the first front suction duct unit 431 and the first front exhaust duct 453, even when a unit supporting the front conveyor belt 217a is inserted or removed with great force during maintenance. A sealing sheet 446 is provided between the front exhaust duct support plate 443 and the first downstream duct 435b of the first front suction duct unit 431. This sealing sheet 446 prevents air from leaking from the joints between the ducts, even when the ducts are configured to be split.

[0089] 2(a), the pre-fixed conveying belt 217b provided in the image forming unit 102 protrudes outward (toward the fixing conveying unit 103) from a support frame (not shown) of the image forming unit 102 in order to stably convey the sheet S carrying unfixed toner to the fixing unit 301 provided in the fixing conveying unit 103, which is a separate housing. As a result, as shown in FIG. 6, a part of the second pre-fixed suction duct unit 432 provided inside the pre-fixed conveying belt 217b protrudes toward the fixing conveying unit 103 at the boundary line V between the image forming unit 102 and the fixing conveying unit 103.

[0090] The portion where this second pre-positioned suction duct unit 432 is provided is positioned in the direction of arrow X so as to overlap with a support pillar (not shown) provided on the front side of the metal sheet constituting the support frame of image forming unit 102. Therefore, unlike first pre-positioned suction duct 431, second pre-positioned suction duct unit 432 is configured so that it cannot be pulled out from the front side (direction of arrow Y) of image forming unit 102.

[0091] With this configuration, when performing maintenance on second pre-positioned suction duct unit 432, it is configured to be removed from the left side (arrow X direction side) of image forming unit 102. Note that a sealing sheet 448 is also provided between second pre-positioned suction duct unit 432 and second pre-positioned exhaust duct 454 to prevent air from leaking from the gap between the ducts.

[0092] Although there is a concern that the second front suction duct unit 432 may be less maintainable, a gap is provided between the second front suction duct unit 432 and the rear side plate 210 in the front-to-rear direction to make it easier to attach to the image forming unit 102. In other words, the rear second front exhaust duct unit 432 is configured to be located closer to the front than the rear side plate 210. Here, the rear side plate 210 is a supporting metal plate provided on the back side of the support frame of the image forming unit 102 described above.

[0093] For this reason, the rear side plate 210 is provided with a duct opening 461 through which the second front exhaust duct 454 connected to the second front suction duct unit 432 passes.

[0094] In addition, when the second pre-fixed suction duct unit 432 is attached from the left (direction of arrow X), the duct joint where the sealing sheet 448 is attached is angled at 30 degrees with respect to the insertion / removal direction of the second pre-fixed suction duct unit 432 so that the sealing sheet 448 that seals the space between the second pre-fixed suction duct unit 432 and the second pre-fixed exhaust duct 454 does not peel off.

[0095] 8, the second front exhaust duct 454 has a boss 456 that fits into a through-hole (not shown) provided in the rear side plate 210, and this boss 456 fits into the aforementioned through-hole, so that the position of the second front exhaust duct 454 does not shift when the second front suction duct unit 432 is inserted or removed. This prevents the position of the second front exhaust duct 454 from shifting due to the force applied when the second front suction duct unit 432 is inserted or removed, and prevents air leakage at the duct joints due to the position shift.

[0096] Next, the connection structure between the pre-fixed exhaust duct unit 430 and the fixing exhaust duct unit 442 will be described with reference to Fig. 9. Fig. 9 is a view of the fixing exhaust duct unit 442 as seen from the rear side. As shown in Fig. 9, the exhaust duct unit 440 is fixed to the rear side plate 210 by an upper support plate 441 and a lower support plate 442.

[0097] Fixing air exhaust duct unit 442 is a duct unit that combines the airflow exhausted from pre-fixed air exhaust duct unit 430 and the airflows formed by fixation pressure exhaust fan 419 and humidity exhaust fan 420. It includes a lower fixation air exhaust filter 422 for capturing VOCs, dust, UFPs, and the like contained in these three airflow systems. Fixing air exhaust duct unit 442 also includes an exhaust port 442a for exhausting air that has passed through lower fixation air exhaust filter 422 in the sheet conveyance direction (arrow X direction) of image forming apparatus 101. While the configuration in which exhaust port 442a is located downstream of lower fixation air exhaust filter 422 has been described here, the lower fixation air exhaust filter 422 may be located downstream of exhaust port 442a as long as it is located in a position through which air exhausted to the outside of image forming apparatus 101 passes. Alternatively, the exhaust port 442a and lower fixation air exhaust filter 422 may be located apart from each other.

[0098] In this embodiment, illustrations are omitted for the configuration of the duct that guides the air taken in by the fixing pressurized exhaust fan 419 and the humidity exhaust fan 420 to the fixing exhaust duct unit 442. The air taken in by the fixing pressurized exhaust fan 419 and the humidity exhaust fan 420 may be directly discharged to the fixing exhaust duct unit 442, or a separate duct unit may be provided between the fixing pressurized exhaust fan 419 and the humidity exhaust fan 420 and the fixing exhaust duct unit 442.

[0099] In the exhaust duct unit 440 of the front exhaust duct unit 430, two air flows are formed by the air passage formed by the first front exhaust duct 453 and the second front exhaust duct 454.

[0100] Here, since space can be secured on the side of the fixing exhaust duct 442 to which the pre-fixed exhaust duct unit 430 is connected even if a post-processing device is installed, the exhaust direction is set to the left side of the main body, and the fixing lower exhaust filter 422 is placed on the left side of the fixing exhaust duct unit 442.

[0101] Therefore, in order to guide the air from pre-fixture exhaust duct unit 430 to lower-fixture exhaust filter 422, it is necessary to bend the airflow by approximately 90 degrees within the duct. In this embodiment, approximately 90 degrees refers to a range of 80 degrees to 100 degrees. Generally, when a bent portion is provided in a duct, pressure loss increases, but the pressure loss can be reduced by increasing the R1 and R2 shapes of duct bent portion 450 relative to the inner widths l1 and l2 of the duct.

[0102] In this embodiment, the inner widths l1 and l2 are 34 mm, and the R dimension (bending radius) is more than twice as large, at 80 mm. Next, to improve maintainability, an appropriate filter size is required from the perspective of filter lifespan, and it is desirable not to increase or decrease the cross-sectional area of ​​the duct. However, from a space perspective, it is difficult to ensure a duct cross-sectional area of ​​the same size as the filter within first pre-suction duct unit 431 and second pre-suction duct unit 432.

[0103] For this reason, it is necessary to increase the cross-sectional area of ​​the duct from exhaust duct 440 of pre-fixed exhaust duct unit 430 to lower fuser exhaust filter 422. In this embodiment, the duct is shaped so that the cross-sectional area of ​​the duct gradually increases toward lower fuser exhaust filter 422, the most downstream part.

[0104] In this embodiment, the filter is arranged to have a vertically elongated shape that is long in the vertical direction (arrow Z direction) in order to further reduce the front-to-rear size of the image forming apparatus 101. Therefore, the duct corresponding to this filter needs to be larger in the vertical direction than in the front-to-rear direction, and the method for expanding the duct in this case is important.

[0105] As mentioned above, when a duct is bent, there is a risk of increased pressure loss at the bent portion, so the angle of the first vertically expanding portion 451, which starts upstream of the duct bend 450, with respect to the horizontal plane is set to 20 degrees or less, thereby reducing the expansion angle.The second vertically expanding portion 452, which is downstream of the duct bend 450, has an expansion angle of 45 degrees, which is larger than the first expansion angle 451, thereby reducing pressure loss throughout the duct.

[0106] Although the duct can be expanded using only the second expansion section 452, the expansion angle would exceed 45 degrees, resulting in excessive pressure loss in the second expansion section 452. However, unlike the present embodiment, if it is possible to increase the size of the image forming apparatus 101 in the front-to-rear direction, the first expansion section 451 may be configured so that the bend is at 90 degrees. In this case, the angle may be approximately the same as that of the second expansion section 452. If a large distance cannot be secured in the front-to-rear direction, it is desirable to make the angle of the first expansion section 451 smaller than that of the second expansion section 452, while making the angle of the second expansion section 452 45 degrees or less.

[0107] In this way, by connecting the pre-fixing exhaust duct unit 430 to the fixing exhaust duct unit 442, the air sucked in by the image forming section 102 in the image forming apparatus 101 can be exhausted through the lower fixing exhaust filter 422 provided in the fixing conveying section 103, which is a housing different from that of the image forming section 102. This allows the airflow for exhausting the air near the fixing unit 301 to be consolidated into one in the image forming apparatus 101 having multiple housings. Therefore, it becomes possible to collect VOCs, UFPs, etc. generated near the fixing section 301 with one filter, improving the workability during maintenance such as filter replacement.

[0108] In the above-described embodiment, the configuration is such that the pre-fixing conveying belts 217a, b are provided, and therefore the first pre-fixing suction duct unit 431 and the second pre-fixing suction duct unit 432 are provided, but if the length of the conveying path from the secondary transfer nip to the fixing nip of the fixing unit 301 is short, the configuration may be such that only the pre-fixing conveying belt 217a and the first pre-fixing suction duct unit 431 are provided.

[0109] Second Embodiment Next, a second embodiment will be described with reference to Fig. 10. In the second embodiment, the configuration of the housing of the image forming apparatus 101 is different from that of the first embodiment.

[0110] FIG. 10 is a schematic cross-sectional view showing the pre-exhaust duct units 430, 430' in the second embodiment.

[0111] In the second embodiment, because the positions of the first and second pre-fixed suction duct units 431 and 432 and the fixing unit 301 are far apart, a configuration will be described in which third and fourth pre-fixed suction duct units 470 and 471 are further provided. Note that the configurations of the pre-fixed exhaust duct unit 430 and the fixing exhaust duct unit 442 are the same as those in the first embodiment, and therefore description thereof will be omitted.

[0112] Even when the third and fourth pre-fixed conveying means 470, 471 are provided downstream of the first and second pre-fixed conveying suction duct units 431, 432 within the first housing of the image forming apparatus 101, pre-fixed conveying suction fans 413e-h must be provided, similar to the pre-fixed conveying suction fans 413a-d. Therefore, there is a risk that the third and fourth pre-fixed conveying suction duct units 470, 471 may suck in VOCs, dust, and the like from the fixing unit 301 provided in the fixing conveying section 103. Therefore, exhaust ducts must be provided in the third and fourth pre-fixed conveying suction duct units 470, 471 and connected to the fixing exhaust duct unit 442, similar to the first and second pre-fixed conveying suction duct units 431, 432. The detailed configuration of the third and fourth pre-fixed conveying suction duct units 470, 471 is similar to that of the first and second pre-fixed conveying suction duct units 431, 432 described above, and therefore will not be described here.

[0113] In this case, it is desirable to join the air flows of the first and second pre-suction duct units 431, 432 and then join the air flows of the third and fourth pre-suction duct units 470, 471. By joining the exhaust ports of each duct unit at one location in this way, air leakage can be prevented without complicating the shape of the joining section.

[0114] Furthermore, when merging with the fixing exhaust duct unit 442, the duct direction needs to be bent by approximately 90 degrees, as with the first and second pre-suction ducts, so it is desirable to increase the radius of curvature relative to the duct's inner width to reduce pressure loss. Preferably, the radius should be at least twice the inner width. When expanding the duct in the vertical direction, it is desirable to set the radius to an angle of approximately 20 degrees, which is smaller than the 45-degree expansion angle of the fixing exhaust duct unit 442, as with the pre-suction duct unit 430. By reducing the expansion angle of the 90-degree bend, pressure loss can be reduced.

[0115] Furthermore, the third and fourth pre-fixed suction duct units 470 and 471 described in the second embodiment may be configured to be provided upstream of the fixing unit 301 in the fixing and conveying section 103.

[0116] In this way, by connecting the pre-fixing exhaust duct units 430, 430' to the fixing exhaust duct unit 442, the air sucked in by the image forming section 102 in the image forming apparatus 101 can be exhausted through the lower fixing exhaust filter 422 provided in the fixing conveying section 103, which is a housing different from that of the image forming section 102. This allows the airflow for exhausting the air near the fixing unit 301 to be consolidated into one in the image forming apparatus 101 having multiple housings. Therefore, it becomes possible to collect VOCs, UFPs, etc. generated near the fixing section 301 with a single filter, improving the workability during maintenance such as filter replacement. [Explanation of symbols]

[0117] 71 Developer exhaust port 72 Pre-transfer charging exhaust port 73 Imaging cooling port 74 Charging exhaust vent 100 Image forming system 101 Image forming device 102 Image forming unit 103 Fixing conveyance section 301 Fixing unit 413 Pre-fixing conveyor intake fan 417 Fixing fan 418 Fixed pressure intake fan 419 Fixing pressure exhaust fan 420 Moisture Exhaust Fan 430 Fixed exhaust duct unit 431 First fixed suction duct unit 431 Second pre-suction duct unit 432 First fixed suction duct unit 433 First fixed pre-suction duct junction 434 Second pre-suction duct junction 435 First fixed suction duct 436 Second pre-suction duct

Claims

1. An image forming apparatus having a first housing having an imaging unit therein for forming a toner image on a sheet, and a second housing having a fixing unit for fixing the toner image formed by the imaging unit onto the sheet, the second housing being provided downstream of the first housing in a sheet conveying direction, a conveyor belt provided in the first housing, the conveyor belt conveying a sheet on which a toner image is formed by the imaging unit to the fixing unit; a first intake fan that draws in air so that the sheet is attracted to the outer circumferential surface of the conveyor belt; a first duct unit provided in the first housing and forming an air passage through which air drawn in by the first intake fan passes; a second intake fan provided in the second housing and configured to draw in air in the vicinity of the fixing unit; a second duct unit provided in the second housing and forming an air passage through which the air flowing in from the first duct unit and the air sucked in by the second intake fan pass, the second duct unit having an exhaust port for exhausting air to the outside of the image forming apparatus and a filter through which the air exhausted from the exhaust port passes; Another conveyor belt is provided downstream of the conveyor belt in the sheet conveying direction and has a plurality of air intakes; another intake fan provided on an inner peripheral portion of the other conveyor belt and configured to draw in air so that the sheet is attracted to an outer peripheral surface of the other conveyor belt; An image forming apparatus comprising:

2. the first intake fan is provided on an inner periphery of the conveyor belt and sucks air through a plurality of intake ports formed in the conveyor belt to adsorb the sheet to an outer periphery of the conveyor belt; 2. The image forming apparatus according to claim 1,

3. the first duct unit has a partition wall portion separating a first airflow through which the air sucked by the intake fan flows and a second airflow through which the air sucked by the other intake fan flows; 2. The image forming apparatus according to claim 1,

4. the first duct unit forms an airflow that causes the air drawn in from the first intake fan to flow toward a rear side of the image forming apparatus; 4. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction.

5. the second duct unit forms an air flow for discharging air toward a downstream side in a sheet transport direction of the image forming apparatus.

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

6. The first duct unit has a cross-sectional area of ​​the duct that increases toward the downstream of the air flow.

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

7. The second duct unit has a cross-sectional area of ​​the duct that increases toward the downstream of the air flow.

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

8. The first duct unit has a bending portion for bending an air flow formed in the first duct unit by approximately 90 degrees.

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

9. The bending radius of the bending portion is larger than the inner width of the first duct unit.

9. The image forming apparatus according to claim 8,

Images