JP2019203962A - Air intake and exhaust duct, air intake and exhaust duct mechanism, and image forming apparatus - Google Patents

Abstract

To make it possible, in an air intake and exhaust duct used for an image forming apparatus, to use one duct for air intake and exhaust purposes with a simple configuration.SOLUTION: An image forming apparatus (100) comprises an apparatus body (12) and an air intake and exhaust unit 10. The air intake and exhaust unit 10 includes an air intake and exhaust duct 70. The air intake and exhaust duct 70 communicates with the inside of the apparatus body (12) at one end and communicates with the outside of the apparatus body (12) at the other end. The air intake and exhaust duct 70 includes a narrow part 74 that has a smaller channel cross sectional area than that of the other portion. The other end of the air intake and exhaust duct 70 is branched into an air intake duct 702 provided with an air intake fan 90 and an air exhaust duct 704 provided with an air exhaust fan 92 at the narrow part 74. The air intake fan 90 and air exhaust fan 92 are not operated simultaneously, and any one of the air intake fan 90 and air exhaust fan 92 is operated or both of which are stopped.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an intake / exhaust duct, an intake / exhaust duct mechanism, and an image forming apparatus. More specifically, the present invention relates to an intake / exhaust duct, an intake / exhaust duct mechanism, and an image forming apparatus that take in air outside the image forming apparatus into the image forming apparatus and exhaust air inside the image forming apparatus to the outside of the image forming apparatus. .

  Patent Document 1 discloses an example of a background art image forming apparatus. The image forming apparatus according to the background art has a blowing guide section having a blowing means for sending air to a blowing port directed to the blocking body in a space between the image forming unit and the fixing unit, and suction for sucking air near the blocking body. A suction air guide portion having a means is provided, the wind from the air blowing port is applied to the blocking body, and the wind hitting the blocking body is sucked into the suction air guiding portion.

JP 2008-250284 A

  In the image forming apparatus of the background art, an intake duct for intake and an exhaust duct for exhaust are provided separately, and the length (cross-sectional shape) of each duct in the direction perpendicular to the air flow direction is the air flow. Since it does not change in direction and is almost the same as the fan unit, a large space is required for installation inside the image forming apparatus, making it difficult to reduce the size of the image forming apparatus.

  Furthermore, if only the exhaust duct is operated to suck air in the image forming apparatus, air is also sucked from the intake duct side, and the air inside the image forming apparatus cannot be efficiently exhausted.

  In order to solve such a problem, it is conceivable to use one duct for intake and exhaust, that is, use an intake / exhaust duct. It is necessary to provide a switching device for switching the air blowing path in the inside, resulting in a problem that the configuration becomes complicated.

  Therefore, a main object of the present invention is to provide a novel intake / exhaust duct, intake / exhaust duct mechanism, and image forming apparatus.

  Another object of the present invention is to provide an intake / exhaust duct, an intake / exhaust duct mechanism, and an image forming apparatus that can use a single duct efficiently for intake and exhaust with a simple structure.

  A first aspect of the present invention is an intake / exhaust duct that forms an air flow path that connects an internal communication port that communicates with an internal space of an apparatus and an external communication port that communicates with an external space of the apparatus. It has one duct and a second duct. The narrow portion is provided between the internal communication port and the external communication port, and the flow channel cross-sectional area of the air flow channel is smaller than the other portions. The first duct is provided with an intake fan that communicates with the external communication port and sucks air outside the device from the external communication port into the device. The second duct is communicated with an external communication port, and an exhaust fan is provided for exhausting air in the apparatus from the external communication port. The first duct and the second duct are branched in the middle of the narrow portion.

  The second invention is dependent on the first invention, and the branch position between the first duct and the second duct is located closer to the internal communication port than the center of the narrow portion in the direction of air flow.

  The third invention is dependent on the first or second invention, and in the narrow portion, the first duct and the second duct are provided adjacent to each other.

  A fourth invention is dependent on any one of the first to third inventions, and the narrow portion is provided with a rectifying rib extending in a direction in which air flows.

  A fifth invention is dependent on any one of the first to fourth inventions, and the external communication port includes a first external communication port communicating with the first duct, and a second external communication port communicating with the second duct. The first external communication port and the second external communication port are separately disposed at positions separated from each other.

  A sixth invention is dependent on any one of the first to fifth inventions, and has a cross-section changing portion that is formed at a connection portion with the narrow portion and the flow passage cross-sectional area gradually changes.

  A seventh aspect of the present invention is an intake / exhaust duct mechanism that includes the intake / exhaust duct of any one of the first to sixth aspects of the invention and includes a fan control unit that can individually control the intake fan and the exhaust fan.

  An eighth invention is according to the seventh invention, and the fan control unit drives either the intake fan or the exhaust fan based on the detected temperature detected by the detecting unit that detects the temperature in the apparatus.

  A ninth invention is an image forming apparatus including the intake / exhaust duct according to any one of the first to sixth inventions.

  A tenth invention is an image forming apparatus provided with the intake / exhaust duct mechanism of the seventh or eighth invention.

  An eleventh invention is dependent on the ninth or tenth invention and further includes a unit member attached to the image forming apparatus, and the narrow portion is provided along a side surface portion of the unit member attached to the image forming apparatus. .

  According to the present invention, in the intake / exhaust duct used in the image forming apparatus, one duct can be used for intake and exhaust with a simple structure.

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

FIG. 1 is an illustrative view showing a schematic configuration when an image forming apparatus according to a first embodiment of the present invention is viewed from the front. FIG. 2 is a schematic perspective view showing the structure of the intake / exhaust duct mechanism. FIG. 3 is a schematic perspective view showing the structure of the intake / exhaust duct mechanism with the second flow path forming member removed. 4 is a schematic cross-sectional view showing the structure of an intake / exhaust duct mechanism provided in the image forming apparatus of FIG. FIG. 5 is a schematic perspective view showing the flow of air in the intake / exhaust duct in the intake mode. FIG. 6 is a schematic perspective view showing the flow of air in the intake / exhaust duct in the exhaust mode. FIG. 7 is a schematic perspective view showing the structure of the intake / exhaust duct mechanism of the second embodiment. FIG. 8 is a schematic sectional view showing the structure of the intake / exhaust duct of the third embodiment.

[First embodiment]
FIG. 1 is an illustrative view showing a schematic configuration when an image forming apparatus 100 according to a first embodiment of the present invention is viewed from the front. An image forming apparatus 100 shown in FIG. 1 is a multifunction machine having a copying function, a printer function, a scanner function, a facsimile function, and the like, and forms a single color image (monochrome image) on a recording medium by an electrophotographic method. The recording medium is not limited to paper made of paper, and a sheet other than paper such as an OHP film can be used. However, a case where paper is used will be described below.

  However, in this specification, among the horizontal directions when the image forming apparatus 100 is viewed from the front, the left side is defined as the left direction, and the right side is defined as the right direction. Of the depth direction when the image forming apparatus 100 is viewed from above (downward), the front side of the image forming apparatus 100 is defined as the front direction (front direction), and the back side of the image forming apparatus 100 is defined as the rear direction (front direction). (Back direction)

  First, the configuration of the image forming apparatus 100 will be schematically described. As shown in FIG. 1, the image forming apparatus 100 includes an apparatus main body 12 including an image forming unit 30 and an image reading apparatus 14 disposed above the apparatus main body 12.

  The image reading device 14 includes a document placing table 16 formed of a transparent material. A document pressing cover 18 is attached above the document placing table 16 through a hinge or the like so as to be freely opened and closed. A document supply tray 20 is provided on the upper surface of the document pressing cover 18, and an ADF (automatic document feeder) is provided therein. The ADF automatically supplies the documents placed on the document supply tray 20 one by one to the image reading position 22 and discharges them to the document discharge tray 24.

  The image reading unit 26 built in the image reading device 14 includes a light source, a plurality of mirrors, an imaging lens, a line sensor, and the like. The image reading unit 26 exposes the document surface with a light source, and guides the reflected light reflected from the document surface to the imaging lens by a plurality of mirrors. Then, the reflected light is imaged on the light receiving element of the line sensor by the imaging lens. The line sensor detects the luminance and chromaticity of the reflected light imaged on the light receiving element, and generates image data based on the image on the document surface. As the line sensor, a charge coupled device (CCD) or a contact image sensor (CIS) is used.

  Although not shown, an operation panel that accepts an input operation such as a print instruction by a user is provided on the front side of the image reading device 14. The operation panel includes a display with a touch panel and a plurality of operation buttons.

  In addition, the apparatus main body 12 is provided with a control unit 28 including a CPU, a memory, and the like. The control unit 28 transmits a control signal to each part of the image forming apparatus 100 in accordance with an input operation to the operation panel, and causes the image forming apparatus 100 to execute various operations.

  The image forming unit 30 includes an exposure unit (light scanning unit) 32, a developing unit 34, a photosensitive drum 36, a cleaner unit (cleaning unit) 38, a charging unit 40, a transfer unit 42, a fixing unit 44, and a toner supply member (toner cartridge). ) 46 and the like, and an image is formed on a sheet conveyed from the sheet feeding cassette 48 and the like, and the image-formed sheet is discharged to a sheet discharge tray 50 provided above the image forming unit 30. As image data for forming an image on a sheet, image data read by the image reading unit 26 or image data transmitted from an external computer is used.

  The photosensitive drum 36 is an image carrier having a photosensitive layer formed on the surface of a cylindrical substrate having conductivity, and is configured to be rotated about its axis by a rotational drive source (not shown) such as a motor. Has been. The charging unit 40 charges the surface of the photosensitive drum 36 to a predetermined potential. The exposure unit 32 is configured as a laser scanning unit (LSU) having a laser emitting portion, a reflection mirror, and the like, and exposes the charged surface of the photosensitive drum 36 to generate an electrostatic latent image corresponding to image data. It is formed on the surface of the photosensitive drum 36. The developing unit 34 includes a developing tank (developing housing) that stores toner, supplies the toner to the surface of the photosensitive drum 36, and visualizes the electrostatic latent image formed on the surface of the photosensitive drum 36 with the toner. (Toner image is formed). A toner concentration detection sensor for detecting the toner concentration is provided inside the developing tank. When the toner concentration detected by the toner concentration detection sensor becomes lower than a predetermined value, the toner is supplied from the toner supply member 46 that stores the toner to the developing tank. The cleaner unit (cleaning means) 38 includes a cleaning blade that comes into contact with the surface of the photosensitive drum 36, a conveying screw, and the like, and removes toner remaining on the surface of the photosensitive drum 36 after development and image transfer. Transport to a box (not shown).

  The transfer unit 42 is a unit for transferring a toner image formed on the surface of the photosensitive drum 36 onto a sheet, and includes a transfer roller 42 a provided so as to press the photosensitive drum 36. During image formation, a predetermined voltage is applied to the transfer roller 42a, whereby a transfer electric field is formed between the photosensitive drum 36 and the transfer roller 42a. Due to the action of the transfer electric field, the toner image formed on the outer peripheral surface of the photosensitive drum 36 is transferred to the sheet while the sheet passes through the transfer nip portion between the photosensitive drum 36 and the transfer roller 42a. The

  The fixing unit 44 includes a heat roller (fixing roller) 44a and a pressure roller 44b, and is disposed above the transfer unit 42 (downstream in the sheet conveying direction). The heat roller 44a is disposed on the paper discharge tray 50 side (left side) with respect to the pressure roller 44b.

  The heat roller 44a is set to have a predetermined fixing temperature (for example, 160 ° C.), and is transferred onto the sheet when the sheet passes through the fixing nip portion between the heat roller 44a and the pressure roller 44b. The toner image is melted, mixed, and pressed, and the toner image is heat-fixed (heat-fixed) on the paper.

  In the apparatus main body 12, a paper transport path L for transporting paper is formed. The paper transport path L is provided for feeding paper transported from the paper feed cassette 48 and the like to the registration roller 56, the transfer unit 42 and the fixing unit 44. However, the image forming apparatus 100 according to the first embodiment is a so-called vertical conveyance type image forming apparatus. Accordingly, in the paper transport path L, the paper is transported from the lower side toward the upper side. Hereinafter, the “paper transport direction” simply refers to the paper transport direction in the paper transport path L (the direction from the lower side to the upper side).

  The paper feed cassette 48 is provided with a paper feed tray for storing paper. Also, in the paper transport path L, there are a pickup roller 52 and a separation roller 54 for taking out the paper stored in the paper feed tray one by one, and the front end of the paper and image information (toner image) on the photosensitive drum 36. A registration roller 56 for aligning the leading edge and a discharge roller 58 for discharging the paper to the paper discharge tray 50 are provided.

  When printing is performed in the apparatus main body 12, the sheets are guided one by one from the sheet feeding cassette 48 to the sheet conveyance path L and conveyed to the registration rollers 56. Then, the sheet is conveyed to the transfer nip portion by the registration roller 56 at a predetermined timing, and the toner image is transferred onto the sheet. Thereafter, the unfixed toner on the paper is thermally fixed by passing through the fixing unit 44 (fixing nip portion). The sheet after heat fixing is discharged to the discharge tray 50 by the discharge roller 58.

  Note that the image forming apparatus 100 as described above may be provided with a manual paper feed tray or an external paper feed unit. In such a case, instead of the paper feed cassette 48, paper may be fed to the paper transport path L from a manual paper feed tray or an external paper feed unit.

  Although not shown, the image forming apparatus 100 is disposed above the fixing unit 44 and is a duct (microparticles) for collecting fine particles generated by heating paper and toner in the fixing unit 44. An exhaust part including a collection duct) is provided. Briefly, the fine particle collecting duct communicates the periphery of the fixing unit 44 (or the sheet conveyance path L on the downstream side of the fixing unit 44) and the exhaust port provided on the side surface of the apparatus main body 12. The fine particle collecting duct is provided with a fine particle collecting filter and an exhaust fan. The filter for collecting the fine particles is such that the paper and toner are heated by the VOC collection filter and / or the fixing unit 44 for collecting volatile organic compounds (VOC) or ozone. A UFP collection filter for collecting UFP (Ultra Fine Particles) generated at the same time. The exhaust fan is a centrifugal fan or an axial fan. However, the exhaust fan is controlled by the control unit 28 described above, and is driven or stopped depending on the operation state of the image forming apparatus 100 or the like.

  Further, the image forming apparatus 100 according to the first embodiment takes in air outside the apparatus main body 12 into the apparatus main body 12 or supplies air inside the apparatus main body 12 to the apparatus separately from the fine particle collecting duct described above. An intake / exhaust section (intake / exhaust duct mechanism) 10 that discharges outside the main body 12 is provided. Hereinafter, the structure of the intake / exhaust portion 10 will be described with reference to the drawings. FIG. 2 is a schematic perspective view showing the structure of the intake / exhaust section 10. FIG. 3 is a schematic perspective view showing the structure of the intake / exhaust section 10 with the second flow path forming member 82 removed. FIG. 4 is a schematic cross-sectional view showing the structure of the intake / exhaust section 10 provided in the image forming apparatus 100 of FIG.

  As shown in FIG. 1, the intake / exhaust portion 10 includes an intake / exhaust duct 70. One end of the intake / exhaust duct 70 communicates with the inside of the apparatus main body 12, and the other end communicates with the outside of the apparatus main body 12. Specifically, one end of the intake / exhaust duct 70 is connected to an internal communication port 102 (see FIG. 4) provided in the vicinity of the sheet conveyance path L and the discharge roller 58 on the downstream side of the fixing unit 44, and the apparatus main body. 12 communicates with the inside. The other end of the intake / exhaust duct 70 is connected to an external communication port 120 provided on the left side surface of the apparatus main body 12, and communicates with the outside of the apparatus main body 12 through the external communication port 120.

  The intake / exhaust duct 70 extends to the right side from the external communication port 120, passes between the image forming unit 30 and the paper discharge tray 50, and is located above the base end portion (end portion on the discharge roller 58 side) of the paper discharge tray 50. And is formed so as to pass between the fixing unit 44 and the paper discharge tray 50.

  As shown in FIGS. 2 to 4, the intake / exhaust duct 70 is formed by a first flow path forming member 80, a second flow path forming member 82, and a third flow path forming member 83.

  The first flow path forming member 80 has a recess that forms part of the intake / exhaust duct 70. The recess is formed in a U-shape that extends in the left-right direction and opens upward. The second flow path forming member 82 is attached to the first flow path forming member 80, thereby covering the concave portion of the first flow path forming member 80. Then, the concave portion is covered with the second flow path forming member 82 and connected to the third flow path forming member 83, whereby the cylindrical intake / exhaust duct 70 is formed. That is, the second flow path forming member 82 forms the top surface of the intake / exhaust duct 70, and the first flow path forming member 80 forms the front side surface, the rear side surface, and the bottom surface of the intake / exhaust duct 70, The path forming member 83 forms the right side portion (portion on the internal communication port 102 side) of the intake / exhaust duct 70.

  However, in the first embodiment, the first flow path forming member 80 is integrated with the frame of the apparatus main body 12. That is, a part of the frame of the apparatus main body 12 functions as the first flow path forming member 80. The second flow path forming member 82 is a plate-like member that is detachably provided on the frame (first flow path forming member 80) of the apparatus main body 12. Therefore, the intake / exhaust duct 70 is formed by attaching the second flow path forming member 82 to the frame of the apparatus main body 12. A part of the first flow path forming member 80 may be separated from the frame of the apparatus main body 12. Further, the third flow path forming member 83 is integrated with the frame of the apparatus main body 12, but may be configured to be separable.

  As shown in FIGS. 1, 3 and 4, the intake / exhaust duct 70 includes a plurality of portions, one end including one end, the other end including the other end, the one end and the other. A narrow portion 74 provided between the end portions is included. More specifically, a guide path portion 72, a narrow portion 74, a cross-section changing portion 76, and a fan holding portion 78 are included in order from one end side (right side). However, in this embodiment, the guide path portion 72 corresponds to the one end portion, and the cross-section changing portion 76 and the fan holding portion 78 correspond to the other end portion. Hereinafter, each part of the intake / exhaust duct 70 will be described in detail.

  As shown in FIG. 1, the guide path portion 72 is connected to a vertically long portion that forms a cylindrical space extending in the vertical direction, and a lower end of the vertically long portion, and on the other end side (left side or the external communication port 120 side). And a connecting portion that forms an extending cylindrical space. In the present embodiment, the vertically long portion is formed by the third flow path forming member 83, and the connecting portion is divided into the first flow path forming member 80 and the second flow path forming member 82. A space (guide route) defined by the vertically long portion and the connecting portion is formed inside the guide route portion 72. The guide path has a substantially L-shaped or J-shaped cross section when viewed from the front side to the back side, and is between the paper discharge tray 50 and the sheet transport path L in the vicinity of the fixing unit 44 and the fixing unit 44. It is provided to pass through. As shown in FIG. 1, the upper end of the guide path portion 72 (the upper end of the vertically long portion) is connected to an internal communication port 102 that communicates with the periphery of the sheet conveyance path L and the discharge roller 58 on the downstream side of the fixing unit 44. Is done. That is, the upper end of the guide path portion 72 is one end of the intake / exhaust duct 70. On the other hand, the left end of the guide path portion 72 (the left end of the connecting portion) communicates with the narrow portion 74. Here, the portion of the guide path portion 72 connected to the narrow portion 74 gradually decreases in the cross-sectional area of the channel toward the narrow portion 74. That is, the portion connected to the narrow portion 74 of the guide path portion 72 functions as a cross section changing portion (a cross section changing portion on one end side). Specifically, as shown in FIG. 4, the vertical dimension (height) of the guide path portion 72 decreases to about ３ toward the connection portion with the narrow portion 74. Since the dimension (width) in the front-rear direction of the guide path portion 72 is substantially the same up to the connection portion with the narrow portion 74, the flow path cross-sectional area of the connection portion between the guide path portion 72 and the narrow portion 74 is It becomes about 1/3 of the flow path cross-sectional area of the path portion 72.

  Next, as shown in FIGS. 3 and 4, the narrow portion 74 connects the guide path portion 72 and the cross-section changing portion 76. Although details will be described later, the intake / exhaust duct 70 includes an intake duct (intake duct 702) and an exhaust duct (exhaust duct 704) that communicate with the external communication port 120 in the middle of the narrow portion 74, respectively. It branches to. The narrow portion 74 has a substantially cylindrical shape that extends in the left-right direction and has a flat shape with a large size in the front-rear direction (width) and a small size in the vertical direction (height) when viewed from the left or right. A space (narrow path) is formed. As shown in FIG. 4, a toner supply member 46 (corresponding to a unit member) is disposed below the narrow portion 74. Each of the narrow portion 74 and the toner supply member 46 is disposed such that the lower surface of the narrow portion 74 and the upper surface of the toner supply member 46 are in contact with or close to each other. That is, the narrow portion 74 is provided in the gap between the paper discharge tray 50 and the toner supply member 46 along the toner supply member 46.

  The cross section changing portion 76 connects the narrow portion 74 and the fan holding portion 78. Inside the cross-section changing portion 76, it extends in the left-right direction, and has a substantially cylindrical shape in which the flow passage cross-sectional area gradually increases from the narrow portion 74 side (one end side) to the fan holding portion 78 side (the other end side). Space (cross-section changing path) is formed. In other words, the cross-section changing portion 76 is configured such that the flow path cross-sectional area gradually decreases from the fan holding portion 78 side (the other end side) toward the narrow portion 74 side (the one end side).

  Specifically, the cross-section changing portion 76 has a top surface (the lower surface of the second flow path forming member 82) provided in a substantially horizontal direction, and an inclination that increases as it goes from the fan holding portion 78 side to the narrow portion 74 side. And a front side surface and a rear side surface facing each other. Therefore, the cross-sectional area of the cross-section changing section 76 gradually decreases from the fan holding section 78 side toward the narrow section 74 side, and therefore the cross-sectional area of the flow path gradually decreases.

  Here, as shown in FIG. 4, the vertical dimension of the cross-section changing portion 76 gradually decreases from the fan holding portion 78 side toward the narrow portion 74 side, and the vertical direction of the connecting portion with the narrow portion 74 is increased. The dimension (height) is reduced to 1/18 of the vertical dimension (height) of the connecting portion with the fan holding portion 78. On the other hand, the dimension (width) in the front-rear direction of the cross-section changing portion 76 on the intake fan 90 side gradually increases from the connection portion with the fan holding portion 78 toward the connection portion with the narrow portion 74, and the intake fan 90 side. The dimension (width) in the front-rear direction at the connection portion between the cross-section changing portion 76 and the narrow portion 74 is the dimension (width) in the front-rear direction of the connection portion between the cross-section changing portion 76 and the fan holding portion 78 on the intake fan 90 side. It is enlarged up to 2 times. In summary, in the cross-section changing portion 76 on the intake fan 90 side, the flow passage cross-sectional area of the connection portion with the narrow portion 74 is about 1 of the flow passage cross section in the flow passage cross-sectional area of the connection portion with the fan holding portion 78. Therefore, the speed of the air flowing into the narrow portion 74 is increased to about 10 times the flow rate of the fan holding portion 78 (intake fan holding portion) on the intake fan 90 side. In addition, the dimension (width) in the front-rear direction of the cross-section changing portion 76 on the exhaust fan 92 side is substantially the same from the connection portion with the fan holding portion 78 to the connection portion with the narrow portion 74. Since the vertical dimension (height) relationship of the cross-section changing portion 76 is the same as that of the intake fan side, the flow path cross-sectional area changes by the ratio of the vertical dimension (height) (see FIG. 4). ).

  The fan holding unit 78 connects the cross-section changing unit 76 and the external communication port 120. That is, the left end of the fan holding portion 78 (the end portion on the external communication port 120 side) is the other end of the intake / exhaust duct 70. Inside the fan holding portion 78, a substantially cylindrical space (external communication path) is formed that extends in the left-right direction and has a substantially rectangular shape when viewed from the left or right.

  As described above, the narrow portion 74 has an air passage cross-sectional area (area in the direction perpendicular to the flow) due to the connection portion with the guide path portion 72 and the connection portion with the cross-section changing portion 76, and the intake / exhaust duct. It is comprised so that it may become small compared with the flow-path cross-sectional area of the other part of 70. In other words, the flow passage cross-sectional area of the narrow portion 74 is configured to be smaller than at least the flow passage cross-sectional area of the portion of the intake / exhaust duct 70 before and after the narrow portion 74.

  More specifically, the size (width) of the narrow portion 74 on the guide path portion 72 side in the front-rear direction is the front-rear direction of the narrow portion 74 on the intake fan 90 side (connection portion with the cross-section changing portion 76 on the intake fan 90 side). It is formed so as to be approximately twice as large as the size (width). On the other hand, the vertical dimension (height) of the narrow portion 74 does not change substantially from the intake fan 90 side to the guide path portion 72 side. Therefore, the channel cross-sectional area on the guide path portion 72 side in the narrow portion 74 is approximately twice the channel cross-sectional area on the intake fan 90 side. Therefore, the cross-section changing section 76 increases the flow velocity to 10 times that of the intake fan 90 portion, and the flow velocity of the air flowing into the narrow portion 74 decreases about 5 times on the guide path portion 72 side. Maintain a speed faster than the part flow rate. Thus, by expanding the dimension (width) in the front-rear direction on the guide path portion 72 side, the toner replenishing member 46 can be indirectly cooled efficiently by the narrow portion 74 having a high flow velocity.

  Note that the size (width) of the narrow portion 74 on the exhaust fan 92 side in the front-rear direction is 1/3 or less on the guide path portion 72 side.

  As described above, the intake / exhaust duct 70 having one end communicating with the inside of the apparatus main body 12 and the other end communicating with the outside of the apparatus main body 12 is formed. However, in this embodiment, in the vertically long portion of the guide path portion 72 in the intake / exhaust duct 70, the direction of air flow is the vertical direction, and the connecting portion, the narrow portion 74, and the cross-section changing portion 76 of the guide path portion 72. And in the fan holding | maintenance part 78, the direction through which air flows is the left-right direction.

  As shown in FIG. 3, the intake / exhaust duct 70 includes an intake duct (corresponding to a first duct) 702 and an exhaust duct (corresponding to a second duct) 704. The intake duct 702 and the exhaust duct 704 are separated by a diversion wall (diversion rib) 802 that divides the internal space of the intake / exhaust duct 70 into two spaces.

  Specifically, the flow dividing wall 802 is provided across the narrow portion 74, the cross-section changing portion 76, and the fan holding portion 78, and the internal space (narrow path, cross-section) of the narrow portion 74, the cross-section changing portion 76, and the fan holding portion 78. The change route and the external communication route) are provided so as to be separated into front and rear.

  Therefore, each of the intake duct 702 and the exhaust duct 704 is formed from the narrow portion 74 to the other end (external communication port 120). However, in this embodiment, the external communication port 120 includes a first external communication port 122 for intake communicating with the intake duct 702 and a second external communication port 124 for exhaust communicating with the exhaust duct 704. The first external communication port 122 and the second external communication port 124 are separately arranged at positions separated from each other.

  In addition, the intake duct 702 and the exhaust duct 704 are provided so as to be lined up in the front-rear direction. Specifically, the intake duct 702 is provided on the back side of the diverting wall 802, and the exhaust duct 704 is provided on the front side of the diverting wall 802. The intake duct 702 and the exhaust duct 704 are provided substantially in parallel.

  However, the end portion (tip portion) on one end side of the flow dividing wall 802 is located in the middle of the narrow portion 74 in the left-right direction (the direction in which air flows). That is, the intake duct 702 and the exhaust duct 704 are branched in the middle of the narrow portion 74 in the air flow direction. Specifically, the front end portion of the flow dividing wall 802 is located on one end side (the guide path portion 72 side or the opposite side of the fan holding portion 78) from the center of the narrow portion 74 in the air flow direction. That is, the intake duct 702 and the exhaust duct 704 are branched on one end side from the center of the narrow portion 74 in the direction in which air flows. Further, at least in the narrow portion 74, the intake duct 702 and the exhaust duct 704 are provided so as to be adjacent to each other in the front-rear direction with the flow dividing wall 802 therebetween.

  At least in the narrow portion 74, the flow dividing wall 802 is formed so as to gradually go to the front side (exhaust duct 704 side) from the other end side toward the one end side. Therefore, in the narrow portion 74, the intake duct 702 gradually increases in size in the front-rear direction and gradually increases in cross-sectional area as it goes from the other end side to the one end side. On the other hand, in the narrow portion 74, the exhaust duct 704 gradually decreases in size in the front-rear direction and gradually decreases in the cross-sectional area of the flow path from the other end side toward the one end side. That is, the front-rear direction dimension (intake-side flow path width) W1 of the narrow portion 74 at the tip position of the branch wall 802, that is, the branch point (intake-side flow path width) W1 ) Greater than W2.

  Furthermore, a rectifying rib 804 provided along the air flow is provided on the intake duct 702 side of the narrow portion 74. Specifically, a plurality of rectifying ribs 804 extending in the left-right direction and provided in parallel to each other are provided on the intake duct 702 side of the narrow portion 74.

  Furthermore, the fan holding portion 78 is provided with an intake fan 90 and an exhaust fan 92. However, the intake fan 90 is provided in the intake duct 702, and the exhaust fan 92 is provided in the exhaust duct 704. The intake fan 90 and the exhaust fan 92 are axial fans, for example, propeller fans. Note that the intake fan 90 and the exhaust fan 92 are not limited to axial fans, and may be centrifugal fans.

  The exhaust direction of the intake fan 90 is set to the right side (one end side). Therefore, the intake fan 90 sucks the air on the other end side, that is, the air outside the apparatus main body 12, and sends it to the one end side, that is, the inside of the intake / exhaust duct 70 (the inside of the apparatus main body 12). The exhaust direction of the exhaust fan 92 is set to the left side (the other end side). Therefore, the exhaust fan 92 sucks air on one end side, that is, air inside the intake / exhaust duct 70 (inside the apparatus main body 12), and sends it to the other end side, that is, outside the apparatus main body 12.

  The intake fan 90 and the exhaust fan 92 are individually controlled by the control unit 28, and are activated (driven) and stopped in accordance with instructions from the control unit. Specifically, the intake / exhaust unit 10 has an intake mode, an exhaust mode, and a stop mode, and the mode is switched by the control unit 28. When the intake mode is executed, the intake fan 90 is activated and the exhaust fan 92 is stopped. When the exhaust mode is executed, the exhaust fan 92 is activated and the intake fan 90 is stopped. When the stop mode is executed, the intake fan 90 and the exhaust fan 92 are stopped. That is, both the intake fan 90 and the exhaust fan 92 are not operated simultaneously, and either one of the intake fan 90 and the exhaust fan 92 is operated or both are stopped.

  Next, the flow of air in the intake / exhaust duct 70 of the first embodiment will be described. FIG. 5 is a schematic perspective view showing the air flow in the intake mode. FIG. 6 is a schematic perspective view showing the air flow in the exhaust mode.

  When the intake mode is executed, the intake fan 90 is activated, and air outside the apparatus body 12 is taken into the intake duct 702 from the first external communication port 122 and sucked into the intake fan 90 as shown in FIG. The The air sucked into the intake fan 90 is discharged to one end side (cross section changing portion 76 side). Thus, in the intake mode, air flows (moves) through the intake duct 702 from the other end side toward the one end side.

  However, in the direction of the air flow (air flow) in the intake mode, the flow passage cross-sectional area gradually decreases when the air passes through the cross-section changing portion 76 and the narrow portion 74, so that the speed (flow velocity) at which the air flows is reduced. Get faster. That is, the speed of air flowing through the intake duct 702 is increased. This increased air flows through the narrow portion 74 of the intake duct 702, flows into the guide path portion 72 as it is, and hardly flows into the narrow portion 74 side on the exhaust fan 92 side. This is because the flow resistance of the narrow portion 74 on the exhaust fan 92 side is larger than the flow resistance on the guide path portion 72 side from the tip position of the flow dividing wall 802, and the increased air flow has inertia. This is because the flow direction is difficult to change. Moreover, the flow path cross section of the guide path part 72 is wider than the flow path cross section of the narrow part 74, the flow path resistance is small, and the air from the narrow part 74 is formed more easily.

  Then, the air that has flowed into the guide path portion 72 passes through the guide path portion 72 and is discharged from one end of the intake / exhaust duct 70 to the periphery of the sheet conveyance path L and the discharge roller 58 on the downstream side of the fixing unit 44. .

  As described above, in the intake mode, the air taken into the intake / exhaust duct 70 from the outside of the apparatus main body 12 flows in the order of the fan holding part 78, the cross-section changing part 76, the narrow part 74, and the guide path part 72. 12 is supplied to the inside.

  When the exhaust mode is executed, the exhaust fan 92 is operated, and the air inside the exhaust duct 704 is sucked into the exhaust fan 92 as shown in FIG. The air sucked into the exhaust fan 92 is discharged to the other end side, and is discharged from the second external communication port 124 to the outside of the apparatus main body 12. Thus, in the exhaust mode, air flows through the exhaust duct 704 from one end side to the other end side.

  However, when the exhaust mode is executed, mainly air from the guide path portion 72 flows into the exhaust duct 704. On the other hand, the air from the intake duct 702 hardly flows into the exhaust duct 704. This is because the intake duct 702 and the exhaust duct 704 are branched from the position of the narrow portion 74 where the pipe resistance from the intake fan 90 side is large, that is, from the center in the flow direction to the guide path portion 72 side. This is because the air from the intake duct 702 having a high pipe resistance hardly flows and the air from the guide path portion 72 having a low pipe resistance flows easily. Further, since the intake duct 702 and the exhaust duct 704 are provided substantially in parallel, air is passed from the duct on the side where the fan is stopped to the duct where the fan is operated, of the intake duct 702 and the exhaust duct 704. In order to flow in, it is necessary to change the direction of air flow by 180 ° (air makes a U-turn). Since such an air flow hardly occurs, the air from the intake duct 702 hardly flows into the exhaust duct 704.

  Therefore, when the exhaust mode is executed, the air in the guide path portion 72 is sucked into the exhaust duct 704, whereby the air around the paper transport path L and the discharge roller 58 on the downstream side of the fixing unit 44 is guided to the guide path. Part 72 is taken in.

  As described above, in the exhaust mode, the air taken from the inside of the apparatus main body 12 flows in the order of the guide path portion 72, the narrow portion 74, the cross-section changing portion 76, and the fan holding portion 78, and is discharged to the outside of the apparatus main body 12. Is done.

  In this first embodiment, the intake duct 702 and the exhaust duct 704 are branched at the position of the narrow portion 74 where the pipe resistance to the intake fan 90 or the exhaust fan 92 is larger than the pipe resistance to the guide path section 72. Therefore, it is possible to prevent air from entering from the duct on the side where the fan is stopped. Therefore, the intake / exhaust duct 70 can be used for intake and exhaust only by switching the driven fan. In addition, since it is not necessary to provide a mechanism for switching the duct at the branch portion between the intake duct 702 and the exhaust duct 704, the intake / exhaust section 10 can have a simple structure.

  Further, according to the first embodiment, in the narrow portion 74, since the intake duct 702 and the exhaust duct 704 are provided adjacent to each other in the front-rear direction, the space inside the apparatus main body 12 can be used effectively. Therefore, it is possible to reduce the size of the apparatus main body 12 and to secure the flow passage cross-sectional areas of the intake duct 702 and the exhaust duct 704.

  Further, according to the first embodiment, since the intake duct 702 and the exhaust duct 704 are branched on one end side from the center of the narrow portion 74, air wraps around from the duct on the side where the fan is stopped. Can be effectively prevented.

  Furthermore, according to the first embodiment, since the narrow portion 74 is provided with the rectifying rib 804 provided along the air flow, the air passing through the narrow portion 74 can be rectified. Further, since the flow passage cross-sectional area of the narrow portion 74 is further reduced by the provision of the rectifying ribs 804, it is possible to effectively prevent air from entering from the duct on the side where the fan is stopped.

  Further, according to the first embodiment, the narrow portion 74 is provided along the toner replenishing member 46, so that the toner replenishing member 46 indirectly through the first flow path forming member 80 by the air flowing through the narrow portion 74. To be cooled. For this reason, the temperature increase of the toner supply member 46 can be suppressed. Further, since the air flowing through the narrow portion 74 is accelerated, the toner replenishing member 46 can be effectively cooled.

  Furthermore, in the first embodiment, the flow dividing wall 802 is formed so as to gradually go to the exhaust duct 704 side as it goes from the other end side to the one end side, so that the intake duct 702 has one end from the other end side. The cross-sectional area of the channel gradually increases toward the side. Such a configuration is effective when it is desired to secure an air flow rate (intake air flow rate) in the intake mode, whereby the toner replenishing member 46 can be effectively cooled.

In this embodiment, the toner replenishing member 46 is described as an example of the unit member provided along the narrow portion 74. However, the present invention is not limited to this. For example, the narrow portion 74 may be formed along the developing unit 34 or the cleaning unit 38. In this way, the developing unit 34 or the cleaning unit 38 can be cooled.
[Second Embodiment]
Since the image forming apparatus 100 of the second embodiment is the same as the image forming apparatus 100 of the first embodiment except that the filter 94 is further provided, the contents different from the first embodiment will be described and duplicated. The explanation will be omitted.

  FIG. 7 is a schematic perspective view showing the structure of the intake / exhaust section 10 of the second embodiment. However, in FIG. 7, the second flow path forming member 82 is omitted. As shown in FIG. 7, the intake / exhaust section 10 of the second embodiment includes a filter 94 that collects particulates and the like. The filter 94 is provided in the exhaust duct 704, and specifically, is disposed on the left side of the exhaust fan 92 (on the downstream side of the air flow in the exhaust duct 704).

  The filter 94 is a UFP collection filter for collecting UFP, for example. The filter 94 may include a VOC collection filter for collecting VOC or ozone in addition to the UFP collection filter.

In the second embodiment, the filter 94 is provided in the exhaust duct 704, so that when the exhaust fan 92 is operated, fine particles generated inside the apparatus main body 12 can be collected. Among the fine particles, particularly UFP, it is said that when the temperature inside the apparatus main body 12 is equal to or lower than a predetermined temperature, UFP is generated by heating the paper or toner in the fixing unit 44 when a printing operation is performed. Is called. Accordingly, the internal temperature of the apparatus main body 12 is detected by a temperature detection unit (not shown), and when the print job is executed when the internal temperature of the apparatus main body 12 is equal to or lower than a predetermined temperature, the exhaust fan 92 is turned off. By operating (exhaust mode is executed), UFP can be efficiently recovered. In addition, since the amount of UFP generated decreases as the internal temperature of the apparatus main body 12 increases, when the internal temperature of the apparatus main body 12 exceeds a predetermined value, the intake temperature mode is shifted and the internal temperature of the apparatus main body 12 does not increase excessively. By doing so, one duct can be effectively used properly.
[Third embodiment]
The image forming apparatus 100 according to the third embodiment is the same as the image forming apparatus 100 according to the second embodiment except that the arrangement of the intake duct 702 and the exhaust duct 704 is different. Therefore, the contents different from the second embodiment will be described. The duplicated explanation will be omitted.

  FIG. 8 is a schematic sectional view showing the structure of the intake / exhaust section 10 of the third embodiment. As shown in FIG. 8, in the intake / exhaust section 10 of the second embodiment, the flow dividing wall 802 is provided so as to divide the internal space of the narrow section 74, the cross-section changing section 76 and the fan holding section 78 vertically. Therefore, the intake duct 702 and the exhaust duct 704 are provided so as to be lined up and down. Specifically, the intake duct 702 is provided below the flow dividing wall 802, and the exhaust duct 704 is provided above the flow dividing wall 802. Further, at least in the narrow portion 74, the intake duct 702 and the exhaust duct 704 are provided so as to be adjacent to each other vertically with the flow dividing wall 802 therebetween. However, in this embodiment, the flow dividing wall 802 does not extend to the external communication port 120, and the intake duct 702 and the exhaust duct 704 merge before the external communication port 120. Accordingly, the external communication port 120 communicates with both the intake duct 702 and the exhaust duct 704. Further, the guide route part 72 communicates directly with the internal communication port 102.

  Also in the third embodiment, the intake / exhaust duct 70 can be used for intake and exhaust only by switching the driven fan. Therefore, in the same manner as in the above-described embodiment, the intake / exhaust duct 70 used in the image forming apparatus 100 can be used for intake and exhaust with a simple structure.

  In each of the above-described embodiments, the image forming apparatus 100 is configured as a multifunction peripheral. However, the image forming apparatus of the present invention may be configured as a printer, a copier, or a facsimile.

  In each of the above embodiments, the image forming apparatus 100 is configured as a monochrome multifunction peripheral. However, the image forming apparatus of the present invention may be configured as a color printing machine or a color multifunction peripheral.

  Further, in each of the above embodiments, the flow dividing wall 802 is formed so as to gradually go to the exhaust duct 704 side from the other end side to the one end side. It may be formed so as to gradually go to the intake duct 702 side as it goes to. In this way, the exhaust duct 704 gradually increases in cross-sectional area as it goes from the other end side to the one end side. On the other hand, the intake duct 702 gradually decreases in the cross-sectional area of the flow path from the other end side to the one end side. Such a configuration is effective when it is desired to ensure the air flow rate (exhaust flow rate) in the exhaust mode.

  Furthermore, in each of the embodiments described above, the rectifying rib 804 is provided on the intake duct 702 side of the narrow portion 74, but may be provided on the exhaust duct 704 side of the narrow portion 74.

  In each of the above-described embodiments, the intake duct 702 and the exhaust duct 704 are provided substantially in parallel. However, the intake duct 702 and the exhaust duct 704 are arranged in the front-rear direction or the vertical direction on the other end side from the narrow portion 74. It may be formed to bend in the direction. In this case, the external communication port 120 may be provided not only on the left side surface of the apparatus main body 12 but also on the other side surface of the apparatus main body 12.

  Furthermore, the specific shapes and the like given in the above embodiments are examples, and can be appropriately changed according to the actual product.

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus 10 ... Intake / exhaust part 12 ... Apparatus main body 30 ... Image forming part 46 ... Toner supply member (toner cartridge)
70: Intake / exhaust duct 702 ... Intake duct (first duct)
704 ... Exhaust duct (second duct)
72 ... Guide path part 74 ... Narrow part 76 ... Cross section changing part 78 ... Fan holding part 90 ... Intake fan 92 ... Exhaust fan 102 ... Internal communication port 120 ... External communication port

Claims (11)

An intake / exhaust duct that forms an air flow path that connects an internal communication port that communicates with the internal space of the device and an external communication port that communicates with the external space of the device,
A narrow portion provided between the internal communication port and the external communication port, wherein the cross-sectional area of the air flow channel is smaller than other portions;
A first duct provided with an intake fan that communicates with the external communication port and sucks air outside the device from the external communication port into the device;
A second duct that is communicated with the external communication port and provided with an exhaust fan that exhausts air in the device from the external communication port;
The first duct and the second duct are intake / exhaust ducts branched in the middle of the narrow portion.   2. The intake / exhaust duct according to claim 1, wherein a branch position between the first duct and the second duct is located closer to the internal communication port than a center of the narrow portion in a direction in which air flows.   The intake / exhaust duct according to claim 1 or 2, wherein the narrow portion is provided so that the first duct and the second duct are adjacent to each other.   The intake / exhaust duct according to any one of claims 1 to 3, wherein the narrow portion is provided with a rectifying rib extending in a direction in which air flows. The external communication port includes a first external communication port that communicates with the first duct, and a second external communication port that communicates with the second duct,
The intake / exhaust duct according to any one of claims 1 to 4, wherein the first external communication port and the second external communication port are separately disposed at positions separated from each other.   The intake / exhaust duct according to any one of claims 1 to 5, further comprising a cross-section changing portion that is formed at a connection portion with the narrow portion and the flow passage cross-sectional area gradually changes.   An intake / exhaust duct mechanism comprising the intake / exhaust duct according to any one of claims 1 to 6 and including a fan control unit capable of individually controlling the intake fan and the exhaust fan.   The intake / exhaust duct mechanism according to claim 7, wherein the fan control unit drives either the intake fan or the exhaust fan based on a detected temperature detected by a detection unit that detects a temperature in the apparatus.   An image forming apparatus comprising the intake / exhaust duct according to claim 1.   An image forming apparatus comprising the intake / exhaust duct mechanism according to claim 7. A unit member attached to the image forming apparatus;
The image forming apparatus according to claim 9, wherein the narrow portion is provided along a side surface portion of the unit member attached to the image forming apparatus.

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