JP2019049669A - Exhaust device and image forming apparatus - Google Patents

Abstract

To reduce a variation in the degree of dirt in the longitudinal direction of collection members, compared with a case where exhaust air is fed to collection members through a channel having a cross section with a certain cylindrical shape.SOLUTION: An exhaust device comprises: collection members 96, 97 that collect dust in air; and an air cleaning unit 91 including a narrowing part 92 that is arranged upstream of the collection members and narrows a channel toward the downstream side, and an enlarging part 93 that is arranged downstream of the narrowing part and enlarges the channel toward the downstream side, where the width L1 of the narrowest portion 92b of the narrowing part is smaller than the length L2 in the longitudinal direction of the collection members.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an exhaust system and an image forming apparatus.

2. Description of the Related Art Conventionally, in an image forming apparatus, those disclosed in Patent Documents 1 and 2 are known as techniques for cleaning exhaust gas.
In JP-A-2015-106070 as Patent Document 1, in the foreign matter collection device (100) for collecting foreign matter such as toner scattered from the developing device (27), the duct (101) is An arrangement is described in which the filter (104) and the second filter (105) are arranged upstream and downstream in the exhaust direction. In the configuration described in Patent Document 1, the bias flow path portion (200f, 200g) is formed in the duct (101), and when the foreign matter collection amount of the first filter (104) increases, the first filter (104) The wind pressure acting on the air increases, moves along the duct (101), and when the amount of foreign matter collection exceeds a predetermined amount, the air reaches the first bias flow path portion (200f) and the air passes through the first filter (104). And a second filter (105) for collecting foreign matter.

  In JP-A-2015-138248 as Patent Document 2, in the exhaust mechanism (38) for exhausting air from the fixing device (37), the second path (382) and the third path (383 The fourth embodiment describes a configuration in which a filter member (390) is disposed in the fourth path (384) after joining in the fourth path (384). In the configuration described in Patent Document 2, discharge electrodes (386, 387) are disposed in the second path (382) and the third path (383), respectively, and UFPs passing through the respective paths (382, 383) are discharged By making the electrodes (386, 387) oppositely charged with each other and making the fourth path (384) electrically adsorb UFPs of the opposite polarity, the size and number of UFPs can be increased and the filter member reduced. It is made easy to collect in (390).

JP, 2015-106070, A ("0016"-"0023", Drawing 2, Drawing 5) JP, 2015-138248, A ("0020"-"0027", Drawing 2)

  This invention makes it a technical subject to suppress the dispersion | variation in the degree of contamination in the longitudinal direction of a collection member compared with the case where exhaust gas is sent to a collection member from the cylindrical flow path with a fixed cross section.

In order to solve the above technical problems, the exhaust system of the invention described in claim 1 is
And
An exhaust member for exhausting the gas inside the housing to the outside;
A collection member disposed in the middle of the gas flow path for collecting dust in the gas;
A narrowed portion disposed upstream of the collection member with respect to the gas exhaust direction and narrowing the flow path toward the downstream, and a downstream portion disposed downstream of the narrowed portion and going downstream And an enlarged portion for expanding the flow path, and the narrowest portion of the narrowed portion has a width of the clean flow portion shorter than the length of the collection member in the longitudinal direction,
It is characterized by having.

The invention according to claim 2 is the exhaust system according to claim 1;
The collection member having a first collection member, and a second collection member disposed downstream of the first collection member in the exhaust direction,
It is characterized by having.

The invention according to claim 3 is the exhaust system according to claim 2.
A first collection member is disposed on the upstream side in the exhaust direction, and a second collection member having a lower pressure loss than the first collection member is disposed on the downstream side.

The invention according to claim 4 is the exhaust system according to any one of claims 1 to 3.
The collection member detachably supported on the housing,
It is characterized by having.

The invention according to claim 5 is the exhaust system according to claim 4 in which
The narrowed portion disposed upstream of the removal direction of the collection member,
It is characterized by having.

The invention according to claim 6 is the exhaust system according to any one of claims 1 to 5,
The size of the flow passage in the short direction of the collecting member is also formed wider corresponding to the enlarged portion.

In order to solve the above technical problems, the image forming apparatus of the invention according to claim 7 is
An image carrier,
A transfer device for transferring an image formed on the image carrier to a medium;
A fixing device for fixing an image transferred to a medium;
The exhaust system according to any one of claims 1 to 6, wherein the gas inside the image forming apparatus is exhausted to the outside.
It is characterized by having.

The invention according to claim 8 relates to the image forming apparatus according to claim 7.
The exhaust device for exhausting the gas from the fixing device;
It is characterized by having.

According to the invention described in claims 1 and 7, the variation in the degree of contamination in the longitudinal direction of the collection member is suppressed as compared with the case where the exhaust gas is sent to the collection member from the cylindrical flow passage having a constant cross section. be able to.
According to the second aspect of the present invention, the air to be exhausted can be cleaned as compared with the case of one collecting member.
According to the third aspect of the present invention, the flow velocity of the gas flowing to the upstream collecting member can be reduced compared to the case where the collecting member with low pressure loss is disposed on the upstream side, Ability can be improved.

According to the invention described in claim 4, the dirty collecting member can be replaced.
According to the invention described in claim 5, it is possible to reduce contamination of the surroundings at the time of removal of the collection member as compared with the case where the narrowed portion is disposed on the downstream side in the removal direction.
According to the invention described in claim 6, the flow velocity of the gas flowing through the collection member can be reduced as compared with the case where the flow passage in the short direction is not expanded, and the collection ability of the collection member is improved. It can be done.
According to the eighth aspect of the present invention, it is possible to exhaust the gas from which the UFP and the odor generated by the fixing device have been removed.

FIG. 1 is an explanatory view of the entire image forming apparatus. FIG. 2 is an explanatory view of an essential part in the vicinity of the curl correcting device according to the first embodiment. FIG. 3 is an enlarged view of an essential part in the vicinity of the fixing device and the curl correcting device of the first embodiment. FIG. 4 is an explanatory view of a space for air blowing according to the first embodiment. FIG. 5 is an explanatory view of the main part of the first duct portion of the first embodiment. FIG. 6 is an explanatory view of the vicinity of the vent hole of the first duct portion of the first embodiment. FIG. 7 is an explanatory view of the main part of the second duct portion of the first embodiment. FIG. 8 is a perspective view of the exhaust system of the first embodiment. FIG. 9 is a perspective view of a cross section taken along line IX-IX of FIG. FIG. 10 is a view seen from the arrow X direction of FIG. 11 is a cross-sectional view taken along line XI-XI of FIG.

Next, specific examples of the embodiment of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
In order to facilitate understanding of the following description, in the drawings, the longitudinal direction is the X-axis direction, the lateral direction is the Y-axis direction, the vertical direction is the Z-axis direction, and arrows X, -X, Y, -Y, The directions shown by Z and -Z or the sides shown are front, rear, right, left, upper, lower or front, rear, right, left, upper, lower.
Further, in the drawings, those in which “•” is described in “o” means an arrow directed from the back of the paper to the front, and those in which “x” is described in “o” are the front of the paper. It means the arrow from the back to the back.
In the following description using the drawings, illustration of members other than members necessary for the description is appropriately omitted for easy understanding.

<Overall Configuration of Image Forming Apparatus>
FIG. 1 is an explanatory view of the entire image forming apparatus.
The image forming apparatus 1 according to the first embodiment is configured as, for example, a full-color image forming apparatus adopting an electrophotographic method. The image forming apparatus 1 includes an automatic document feeder 2 for automatically conveying a document (not shown) to the reading position on the upper portion of the apparatus body 1a, and an image reading device for reading an image of a document (not shown) on a document placing glass 4 It has three.

  The image reading device 3 is an image of a document (not shown) conveyed so as to pass the reading position of the document placing glass 4 by the automatic document feeder 2 or an image of a document not shown placed on the document placing glass 4 Is imaged by the imaging lens 8 on the image reading element 9 by the imaging lens 8 via the full rate mirror 7a and the half rate mirror 7b while the light source 6 illuminates the image of the original (not shown). It is configured as follows.

  The image forming apparatus 1 holds a plurality of image forming apparatuses 10 as an example of an image forming unit for forming a toner image to be developed with toner constituting a developer, and the toner images formed by the respective image forming apparatuses 10 The intermediate transfer device 20 is conveyed to a secondary transfer position where secondary transfer is finally performed on the recording sheet 5 as an example of the recording medium, and the required recording sheet 5 to be supplied to the secondary transfer position of the intermediate transfer device 20 , A fixing device 40 for fixing the toner image on the recording sheet 5 secondarily transferred by the intermediate transfer device 20, and the recording sheet 5 subjected to the fixing process by the fixing device 40. Curl correction device 60 as an example of the correction means for correcting the curvature (curl) of the lens. The alternate long and short dash line in FIG. 1 indicates the main transport path on which the recording sheet 5 is transported inside the image forming apparatus 1.

  The image forming device 10 is a four image forming device 10Y, 10M, 10C, 10K that exclusively forms four color toner images of yellow (Y), magenta (M), cyan (C) and black (K), respectively. It is configured. In these four imaging devices 10 (Y, M, C, K), the imaging device 10 Y for yellow (Y) is relatively upward on the right side of the device main body 1 a, and the imaging device 10 K for black (K) Are arranged to be relatively lower on the left side of the apparatus body 1a.

  The image forming apparatuses 10 (Y, M, C, K) for yellow (Y), magenta (M), cyan (C) and black (K) are, as shown in FIG. The photosensitive drum 11 is rotated, and devices as an example of the following toner image forming means are mainly disposed around the photosensitive drum 11. The main devices are a charging device 12 for charging the peripheral surface (image holding surface) of the photosensitive drum 11 on which an image can be formed, to a required potential, and image information on the charged peripheral surface of the photosensitive drum 11 Exposure device 13 as an example of an electrostatic latent image forming unit that forms an electrostatic latent image (for each color) having a potential difference by irradiating light based on a signal) and the corresponding electrostatic latent image , M, C, and K), and developing devices 14 (Y, M, C, and K) as an example of developing means for developing the toner images into toner images, and the respective toner images on the intermediate transfer device 20. A primary transfer device 15 (Y, M, C, K) as an example of a primary transfer means for transferring and an attached substance such as toner remaining on the image holding surface of the photosensitive drum 11 after primary transfer is removed Drum cleaning devices 16 (Y, M, C, K) and the like to be cleaned.

  The photosensitive drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or cylindrical base material to be grounded. The photosensitive drum 11 is supported so as to rotate in the direction indicated by the arrow A when power is transmitted from a driving device (not shown).

  The charging device 12 is configured of a contact type charging roll disposed in contact with the photosensitive drum 11. The charging device 12 has a cleaning roll 121 that cleans the surface thereof. The charging device 12 is supplied with a charging voltage. When the developing device 14 performs reversal development as the charging voltage, a voltage or current of the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. As the charging device 12, a non-contact charging device such as scorotron disposed on the surface of the photosensitive drum 11 in a non-contact state may be used.

  The exposure device 13 irradiates the photosensitive drum 11 with light according to the image information by means of LEDs (Light Emitting Diodes) as a plurality of light emitting elements arranged along the axial direction of the photosensitive drum 11 to thereby form an electrostatic latent image. And an LED print head to form the Note that as the exposure device 13, one that deflects and scans a laser beam configured according to image information along the axial direction of the photosensitive drum 11 may be used.

  Each of the developing devices 14 (Y, M, C, K) has a developing roll that holds the developer and conveys it to a developing area facing the photosensitive drum 11. A developing bias voltage is supplied between the developing roll and the photosensitive drum 11 from a power supply (not shown) to the developing device 14.

  The primary transfer device 15 (Y, M, C, K) is a contact type provided with a primary transfer roll which contacts and rotates around the photosensitive drum 11 via the intermediate transfer belt 21 and is supplied with a primary transfer voltage. The transfer device of As the primary transfer voltage, a direct current voltage having a polarity opposite to the charge polarity of the toner is supplied from a power supply (not shown).

  The drum cleaning device 16 has a cleaning plate which is disposed in contact with the circumferential surface of the photosensitive drum 11 after the primary transfer with a required pressure and removes and removes deposits such as residual toner. As the cleaning plate, a plate-like member (for example, a blade) made of a material such as rubber is used.

  The intermediate transfer device 20 is disposed to be above the image forming devices 10 (Y, M, C, K) as shown in FIG. The intermediate transfer device 20 is an intermediate transfer belt as an example of an intermediate transfer member which rotates in the direction indicated by the arrow B while passing through the primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll). 21, a plurality of belt support rolls 22 to 25 rotatably holding the intermediate transfer belt 21 in a desired state from the inner surface thereof, and the outer peripheral surface of the intermediate transfer belt 21 supported by the belt support roll 22 After passing through the secondary transfer device 26 as an example of the secondary transfer means disposed on the image holding surface side and performing secondary transfer of the toner image on the intermediate transfer belt 21 onto the recording sheet 5, and after passing through the secondary transfer device 26 A belt cleaning device 27 mainly removes toner, paper dust, and the like adhering to the outer peripheral surface of the intermediate transfer belt 21 and removes the matter.

  As the intermediate transfer belt 21, for example, an endless belt made of a material in which a resistance regulator such as carbon black is dispersed in a synthetic resin such as a polyimide resin or a polyamide resin is used. Further, the belt support roll 22 is configured as a back support roll for secondary transfer, the belt support roll 23 is configured as a drive roll that is rotationally driven by a drive device (not shown), and the belt support roll 24 forms an image of the intermediate transfer belt 21. The belt support roll 25 is configured as a surface application roll that forms a surface, and the belt support roll 25 is configured as a tension application roll that applies tension to the intermediate transfer belt 21.

As shown in FIG. 1, the secondary transfer device (secondary transfer roll) 26 is at the secondary transfer position, which is the outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 22 in the intermediate transfer device 20. This is a contact type transfer device provided with a secondary transfer roll that rotates in contact with the circumferential surface of the intermediate transfer belt 21 and is supplied with a secondary transfer voltage. Further, to the belt supporting roll 22 of the secondary transfer roll 26 or the intermediate transfer device 20, a direct current voltage having a polarity opposite to or the same as the charging polarity of the toner is supplied from a power source (not shown) as a secondary transfer voltage. .
The primary transfer device 15 and the intermediate transfer device 20 constitute a transfer device 15 + 20 for transferring the image on the photosensitive drum 11 to the recording sheet 5.

  As shown in FIG. 1, the belt cleaning device 27 is disposed so as to be in contact with a partially open container-like main body 270 and the peripheral surface of the intermediate transfer belt 21 after secondary transfer with a required pressure. It consists of a cleaning plate 271 that removes and cleans up any extraneous matter such as residual toner, and a delivery member 272 such as a screw auger that transports the extraneous matter such as toner removed by the cleaning plate 271 to be collected and delivered to a recovery device (not shown). It is done. As the cleaning plate 271, a plate-like member (for example, a blade) made of a material such as rubber is used.

  The fixing device 40 is heated by a heating means so as to rotate in the direction indicated by the arrow and to keep the surface temperature at a predetermined temperature while inside the housing (not shown) in which the inlet and the outlet of the recording sheet 5 are formed. A heating rotary body 41 in the form of a roll or a belt, and a pressure rotary body 42 in the form of a belt or a roll which contacts and rotates at a predetermined pressure substantially along the axial direction of the heating rotary body 41; It is arranged and configured. In the fixing device 40, the contact portion where the heating rotary member 41 and the pressing rotary member 42 are in contact serves as a fixing processing unit that performs necessary fixing processing (heating and pressing). The configuration of the fixing device 40 will be described in detail later.

  The curl correction device 60 curves the recording sheet 5 discharged from the fixing device 40 in the direction opposite to the pressure contact direction of the contact portion where the heating rotating body 41 of the fixing device 40 and the pressing rotating body 42 contact. In the form of a roll or belt in contact with a first correction rotating body 61 in the form of a belt or roll to be conveyed and at a predetermined pressure in a state substantially along the axial direction of the first correction rotating body 61 A second correction rotating body 62 and the like are disposed. A pressure contact portion where the first correction rotary body 61 and the second correction rotary body 62 are in pressure contact with each other serves as a curl correction portion. The configuration of the curl correction device 60 will be described in detail later.

  The sheet feeding device 30 is disposed at a lower position along the vertical direction of the image forming device 10 (Y, M, C, K). The sheet feeding device 30 is configured to feed a plurality of (or a single) sheet containing body 31 accommodating the recording sheets 5 of desired size, type, etc. in a stacked state, and sending out the recording sheets 5 one by one from the sheet containing body 31. The apparatus 32 is mainly configured. The sheet container 31 is attached, for example, by a guide rail (not shown) so that the sheet container 31 can be pulled out to the front side of the apparatus main body 1a (a side surface facing the user at the time of operation).

  Examples of the recording paper 5 include thin paper such as plain paper and tracing paper used in electrophotographic copying machines, printers, etc., or OHP sheets. In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper 5 is preferably as smooth as possible. For example, coated paper obtained by coating the surface of plain paper with a resin, art paper for printing, etc. A so-called thick paper or the like having a relatively large basis weight can be suitably used.

  Between the sheet feeding device 30 and the secondary transfer device 26, as shown in FIG. 1, one or more sheet conveying roll pairs for conveying the recording sheet 5 delivered from the sheet feeding device 30 to the secondary transfer position. A sheet feeding / conveying path 34 constituted by a conveying guide 33 and a conveying guide (not shown) is provided along the vertical direction on the left side surface of the apparatus main body 1a. The sheet conveying roll pair 33 disposed at a position immediately before the secondary transfer position in the sheet conveying path 34 is configured as, for example, a roll (resist roll) that adjusts the conveyance timing of the recording sheet 5. Further, the recording sheet 5 after secondary transfer delivered from the secondary transfer device 26 is conveyed to the fixing device 40 and the curl correction device 60 in a region extending from the secondary transfer device 26 to the upper side of the curl correction device 60. A sheet conveyance path 35 is provided as an example of a first conveyance path for the purpose. The sheet conveyance path 35 is disposed along the vertical direction which is the first conveyance direction.

  In the upper part of the curl correction device 60, a conveyance for discharging the recording sheet 5 whose curl is corrected by the curl correction device 60 to the first sheet discharge unit 51 provided in the upper part (upper end face) of the apparatus main body 1a. A first discharge conveyance path 44 provided with a roll 52 and a first sheet discharge roll pair 43 is provided.

  Further, on the upper part of the curl correction device 60, the recording sheet 5 whose curl has been corrected by the curl correction device 60 is placed along the outer surface (upper end surface) of the apparatus main body 1a having a conveyance direction different from the sheet conveyance path 35. While conveying along a substantially horizontal direction, which is the conveyance direction of the sheet, and conveying and discharging to a stack tray 71 as an example of a post-processing apparatus provided on one side surface (right side surface) of the apparatus main body 1a A second discharge conveyance path 36 is provided as an example of the path. The stack tray 71 is configured to be movable in the vertical direction and the longitudinal direction, and the discharge positions of the recording sheets 5 discharged from the image forming apparatus 1 are made different in the vertical direction and the longitudinal direction every plural sheets (plural or single). It is configured to be freely contained. The post-processing apparatus is not limited to the stack tray 71, and may be a merging process for merging other sheets with the recording sheet 5, a punching process or a bending process for the recording sheet 5, or the like. Any post-processing may be performed.

  The second discharge conveyance path 36 includes a plurality of paper conveyance roll pairs 37 for conveying the recording paper 5, and conveyance guides 38a and 38b arranged to face the recording paper 5 in the vertical direction. The sheet discharge portion of the apparatus main body 1a is provided with an opening 39 for sheet discharge and a sheet discharge roll pair 39a.

  Further, above the curl correction device 60, a first switching gate 45 for switching between the first discharge conveyance path 44 and the second discharge conveyance path 36 is provided. The first sheet discharge roll pair 43 is configured such that the rotation direction can be switched between the normal rotation direction (discharge direction) and the reverse rotation direction. Further, on the front side of the first sheet discharge roll pair 43, a second switching gate 46 for switching the conveyance direction of the recording sheet 5 is provided. In the case of forming an image on both sides of the recording paper 5, after the rear end of the recording paper 5 on which the image is formed on one side passes the second switching gate 46, the rotation direction of the first paper discharge roll pair 43 is Switch from the normal direction (discharge direction) to the reverse direction. The recording sheet 5 conveyed in the reverse rotation direction by the first sheet discharge roll pair 43 is switched in the conveyance path in the horizontal direction by the second switching gate 46 so that it extends substantially vertically along the side surface of the apparatus main body 1a. The sheet is conveyed to the formed conveying path 48 for both sides. The duplex conveying path 48 includes a sheet conveying roll pair 49 for conveying the recording sheet 5 to the sheet conveying roll pair 33 in a state where the front and back sides are reversed, a conveying guide (not shown), and the like. Reference numeral 47 denotes a sheet conveyance roll pair for conveying the recording sheet 5 fed from the sheet storage body 31 located below and the manual feed tray (not shown) to the sheet conveyance roll pair 33.

  In FIG. 1, reference numerals 145 (Y, M, C, K) are formed in a cylindrical shape extending in a direction orthogonal to the paper surface, and are arranged along the horizontal direction to correspond to the corresponding developing devices 14 (Y, M, C, 6 shows toner cartridges as an example of a developer container containing a developer containing at least a toner to be supplied to K).

  The toner cartridges 145 (Y, M, C, K) are disposed in the upper portion of the apparatus main body 1a in the vicinity of the lower side of the second discharge conveyance path 36. To explain further, the second discharge conveyance path 36 is located below the first sheet discharge portion 51 constituting the upper end surface which is the outer surface of the apparatus main body 1a, and a plurality of toner cartridges 145 (Y, M, C, K) It is placed close to the outer circumference of the. In this embodiment, in order to secure the amount of toner (developer) contained inside the toner cartridge 145 (Y, M, C, K), the volume of the toner cartridge 145 (Y, M, C, K) Diameter) is set as large as possible. Also, the toner cartridge 145K containing the black (K) toner has a volume (diameter) in comparison with other color toner cartridges 145 (Y, M, C) in consideration of the usage frequency (usage amount) of toner. ) Is set large. Therefore, the toner cartridge 145 (Y, M, C, K) is disposed in the upper portion of the apparatus main body 1a from the right side surface of the apparatus main body 1a to the fixing device 40 and the curl correction device 60. The black (K) toner cartridge 145 K is in a position close to the fixing device 40 with heat generation and the curl correcting device 60 through which the heated recording sheet 5 immediately after fixing passes. Further, all the toner cartridges 145 (Y, M, C, K) including the color toner cartridges 145 (Y, M, C) have a second discharge conveyance path through which the heated recording sheet 5 immediately after fixing passes. It is disposed close to the lower side of 36. The toner cartridges 145 (Y, M, C, K) are disposed at positions susceptible to thermal influences from the recording sheet 5 passing through the fixing device 40, the curl correcting device 60, or the second discharge conveyance path 36. .

  Below the respective toner cartridges 145 (Y, M, C, K), the toners supplied from the toner cartridges 145 (Y, M, C, K) correspond to the developing devices 14 (Y, M, C, K). Toner conveying devices 146 (Y, M, C, K) for conveying the toner to each of

  Further, reference numeral 200 in FIG. 1 denotes a control device that generally controls the operation of the image forming apparatus 1. The control device 200 includes a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), or a bus connecting the CPU, the ROM, and the like (not shown), a communication interface, and the like.

  Further, reference numeral 70 in FIG. 1 denotes a photosensitive unit including the photosensitive drum 11, the charging unit 12 and the drum cleaning unit 16 constituting the image forming apparatus 10, or the developing unit constituting the developing unit 14 with respect to the apparatus main body 1a. The guide member which guides when attaching and removing is shown.

<Operation of Image Forming Apparatus>
Hereinafter, a basic image forming operation by the image forming apparatus 1 will be described.

  Here, a full color image is formed by combining toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K). The operation in the mode will be described.

  The image forming apparatus 1 is controlled by the control device 200, and command information for requesting a full-color image forming operation (print) from an operation panel (not shown) mounted on the image reading device 3 or a user interface or printer driver (not shown) When received, the four image forming devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 26, the fixing device 40, the curl correction device 60, etc. are started.

  Then, in each image forming apparatus 10 (Y, M, C, K), as shown in FIG. 1, first, each photosensitive drum 11 rotates in the direction indicated by arrow A, and each charging device 12 The surface of the body drum 11 is charged to a desired polarity (minus polarity in the first embodiment) and a potential. Subsequently, an image obtained by the exposure device 13 converting the information of the image input to the image forming apparatus 1 into each color component (Y, M, C, K) with respect to the surface of the photosensitive drum 11 after charging. The light emitted is emitted based on the signal of (1), and an electrostatic latent image of each color component constituted by a required potential difference is formed on the surface of the light.

  Subsequently, each of the image forming devices 10 (Y, M, C, K) is charged to the required polarity (minus polarity) with respect to the electrostatic latent image of each color component formed on the photosensitive drum 11. Toners of colors (Y, M, C, K) are respectively supplied from developing rollers and electrostatically attached to perform development. By this development, the electrostatic latent images of the respective color components formed on the respective photosensitive drums 11 are visualized as toner images of four colors (Y, M, C, K) developed with the toners of the corresponding colors. Be Toners are appropriately supplied from the toner cartridges 145 (Y, M, C, K) to the developing devices 14 of the image forming devices 10 (Y, M, C, K).

  Subsequently, when the toner images of the respective colors formed on the photosensitive drums 11 of the image forming devices 10 (Y, M, C, K) are conveyed to the primary transfer position, the primary transfer devices 15 (Y, M, M, C and K) primarily transfer the toner images of the respective colors in a state where they are sequentially superimposed on the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20.

  Further, in each of the image forming apparatuses 10 (Y, M, C, K) where the primary transfer has been completed, the drum cleaning device 16 removes the adhering matter so as to scrape it, and the surface of the photosensitive drum 11 is cleaned. As a result, each image forming apparatus 10 (Y, M, C, K) is made ready for the next image forming operation.

  Subsequently, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and conveyed to the secondary transfer position. On the other hand, the sheet feeding device 30 feeds the required recording sheet 5 to the sheet feeding conveyance path 34 in accordance with the image forming operation. In the sheet feeding / conveying path 34, a sheet conveying roll pair 33 as a registration roll feeds the recording sheet 5 to the secondary transfer position at the transfer timing and supplies it.

  At the secondary transfer position, the secondary transfer device 26 collectively and secondarily transfer the toner image on the intermediate transfer belt 21 onto the recording sheet 5. Further, in the intermediate transfer device 20 in which the secondary transfer is completed, the belt cleaning device 27 removes and cleans the extraneous matter such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

  Subsequently, the recording paper 5 on which the toner image has been secondarily transferred is separated from the intermediate transfer belt 21 and then conveyed to the fixing device 40 via the paper conveyance path 35. In fixing device 40, necessary fixing processing (heating and heating) is performed by introducing recording sheet 5 after secondary transfer into a contact portion between rotating heating rotary body 41 and pressurizing rotary body 42 and passing it. To fix the unfixed toner image on the recording sheet 5. The recording sheet 5 after fixing is conveyed to the curl correction device 60 along the sheet conveyance path 35, and forms first and second correction portions forming a contact portion in a convex-concave relationship in the reverse direction to the fixing device 40. By passing through the contact portion with the rotating members 61 and 62, the curl formed by the fixing device 40 is corrected. Thereafter, in the case of an image forming operation for only forming an image on one side of the recording sheet 5 whose curl has been corrected, the recording sheet 5 is placed on the stack tray 71 installed on the right side of the apparatus main body 1a by the sheet transport roll pair 37. The sheet is discharged, or is discharged by the first sheet discharge roll pair 43 to the first sheet discharge unit 51 installed at the upper part of the apparatus main body 1a.

  Further, when forming an image on both sides of the recording sheet 5, the recording sheet 5 having the image formed on one side is conveyed to the first sheet discharge roll pair 43, and the first sheet discharge roll pair 43 performs the first sheet The recording sheet 5 is reversely rotated by reversing the rotation direction of the first sheet discharge roll pair 43 without being discharged to the discharge unit 51, and then conveyed again to the secondary transfer device 26 via the duplex conveyance path 48. The toner image is transferred to the back surface of the recording sheet 5. The recording sheet 5 on which the toner image is transferred to the back surface is conveyed to the fixing device 40 through the sheet conveyance path 35 and subjected to fixing processing (heating and pressing) by the fixing device 40 and curled by the curl correction device 60. Is discharged, for example, to a stack tray 71 or the like installed on the right side surface of the apparatus main body 1a by the sheet conveyance roll pair 37 or the like.

  By the above-described operation, the recording sheet 5 on which a full color image formed by combining four color toner images is formed is output. In the image forming apparatus 1, of course, a monochrome image may be formed on the recording paper 5 using only the black (K) imaging device 10K.

<Configuration of Characteristic Portion of Image Forming Apparatus>
FIG. 2 is an explanatory view of an essential part in the vicinity of the curl correcting device according to the first embodiment.
In the image forming apparatus 1 according to the first embodiment, as shown in FIGS. 1 and 2, the curl correction is performed between the sheet conveyance path 35 as the first conveyance path and the black (K) toner cartridge 145K. A plurality of (three in the illustrated example) blower fans 64 are provided as an example of a blower for blowing air to the recording paper 5 passing through the apparatus 60 and the paper conveyance path 35.

  In addition, the curl correction device 60 has guide members 65 and 66 for guiding the airflow (air flow) from the plurality of blower fans 64 in the circumferential direction of the curl correction belt 61 as an example of the first correction rotating body. doing. The guide members 65 and 66 are disposed on the upper and lower sides of the curl correction belt 61, and are provided with an air inlet on the side of the blower fan 64, and are arranged to cover the outer periphery of the curl correction belt 61 over approximately a half circumference.

FIG. 3 is an enlarged view of an essential part in the vicinity of the fixing device and the curl correcting device of the first embodiment.
As shown in FIG. 3, the blower fan 64 is provided in the apparatus main body 1 a via a blower space 80 formed between the toner cartridge 145 (Y, M, C, K) and the second discharge conveyance path 36. Take in external air from the right side. A thin plate-like covering member 81 is provided on the top of the toner cartridge 145 (Y, M, C, K) to cover the top of the toner cartridge 145 (Y, M, C, K). One end portion 81 a of the covering member 81 is connected to the lower end portion of the blower fan 64. The covering member 81 is substantially on the top of the toner cartridge 145 (Y, M, C, K) through a curved portion 81 b curved along the outer peripheral shape of the black (K) toner cartridge 145 K from the lower end portion of the blower fan 64. A flat plate portion 81c disposed horizontally is provided. The tip end of the flat plate portion 81c is disposed above the yellow (Y) toner cartridge 145Y so as to avoid the sheet conveyance roll pair 37.

  The blower fan 64 sucks in air through an opening 39 for paper discharge or a louver (not shown) opened on the right side surface of the apparatus main body 1a. The sucked air is sent to the blower fan 64 through the air space 80 formed between the covering member 81 and the conveyance guide 38 b located below the second discharge conveyance path 36.

FIG. 4 is an explanatory view of a space for air blowing according to the first embodiment.
In FIG. 4, the conveyance guide 38a above the second discharge conveyance path 36 is provided with a plurality of slit-like openings for discharging the heat of the recording sheet 5 conveyed in the second discharge conveyance path 36 to the outside. A louver 85 is provided.

  In FIG. 3, a double duct 86 is provided below the blower fan 64 to cover the sides of the heating rotary body 41 of the fixing device 40 in a double manner. The double duct 86 is formed of a first duct portion 88 formed of a space covered by a sheet metal 87 having a side surface substantially L-shape disposed on the side of the heating rotary body 41 of the fixing device 40; It is disposed on the back side (toner cartridge side) of a sheet metal 87 forming the duct portion 88, and is partitioned in a rectangular shape in a cross section along the longitudinal direction of the fixing device 40 between the fixing device 40 and the toner cartridge 145K. A second duct portion 89 forming an air flow path consisting of a closed space is provided. The first duct portion 88 and the second duct portion 89 are provided along substantially the entire length of the fixing device 40 in the longitudinal direction.

FIG. 5 is an explanatory view of the main part of the first duct portion of the first embodiment.
FIG. 6 is an explanatory view of the vicinity of the vent hole of the first duct portion of the first embodiment.
In FIG. 5, the second duct 89 has a front end 89a of the apparatus body 1a closed. In FIG. 6, in the first duct portion 88, the end portion 88a on the back side of the device body 1a is closed. The first duct portion 88 is in communication with the second duct portion 89 through a plurality of vent holes 89 b opened in the sheet metal 87 at an end portion 88 a on the back side of the apparatus body 1 a.

FIG. 7 is an explanatory view of the main part of the second duct portion of the first embodiment.
FIG. 8 is a perspective view of the exhaust system of the first embodiment.
FIG. 9 is a perspective view of a cross section taken along line IX-IX of FIG.
FIG. 10 is a view seen from the arrow X direction of FIG.
11 is a cross-sectional view taken along line XI-XI of FIG.

  In FIG. 7, the second duct portion 89 is connected to the exhaust duct 90 on the back side of the apparatus body 1 a. 7 to 9, the exhaust duct 90 has its lower end connected to the second duct portion 89 and extends upward. In FIGS. 8 and 9, the upper end portion of the exhaust duct 90 is connected to the upstream end of the clean flow portion 91. In FIGS. 8-11, the clean flow part 91 has the constriction part 92 arrange | positioned upstream in the exhaust direction. The narrowed portion 92 is formed such that the width direction (left and right direction, Y direction) of the gas flow passage 92a narrows toward the downstream side with respect to the gas discharge direction Ya.

An enlarged portion 93 is connected to the downstream side of the narrowed portion 92. In FIG. 10, the enlarged portion 93 is formed such that the width direction of the flow path 93a (longitudinal direction of the filters 96 and 97 described later) is expanded toward the downstream side of the exhaust direction Ya. In FIG. 11, in the enlarged portion 93 of the first embodiment, the height in the vertical direction (the short direction of the filters 96 and 97 described later) such that the flow path 93 a spreads as the ceiling 93 b and the bottom 93 c also go downstream. Is formed.
The narrowed portion 92 and the enlarged portion 93 constitute a clean flow portion 91 of the first embodiment.

On the downstream side of the enlarged portion 93, a filter chamber 94 as an example of a storage portion of the collection member is connected.
In the filter chamber 94, a UFP filter 96 as an example of a first collection member is accommodated on the upstream side in the exhaust direction Ya. The UFP filter 96 is formed of a non-woven fabric in a repeatedly folded shape, a so-called pleated shape, or a curtain shape. The UFP filter 96 is a commercially available filter and collects ultra fine particle (UFP: Ultrafine Particle) with a diameter of 0.1 μm or less, which is a target of environmental regulations (blue angel) in Europe, paper powder, floating toner, etc. It is a possible filter.

In the filter chamber 94, an activated carbon filter 97 as an example of a second collection member is accommodated downstream of the UFP filter 96. The activated carbon filter 97 is a filter having a corrugated honeycomb structure in which activated carbon is dispersed, and a commercially available filter can be used. The activated carbon filter 97 is mainly a filter that can remove the odor in the gas. In Example 1, the activated carbon filter 97 has a lower pressure drop (pressure loss) than the UFP filter 96 is used. That is, the activated carbon filter 97 allows air and exhaust to pass more easily than the UFP filter 96.
The collection members 96 + 97 of the first embodiment are configured by the respective filters 96 and 97.

  Each of the filters 96 and 97 in the first embodiment is movably supported along a guide rail 94 a as an example of a guide member formed on the bottom and the ceiling of the filter chamber 94. Therefore, the filters 96 and 97 of the first embodiment are detachably supported in the left-right direction with respect to the filter chamber 94. In each of the filters 96 and 97, knob portions 96a and 97a are formed at the left end of the housing. Therefore, the operator can operate the knobs 96a and 97a to attach and detach the filters 96 and 97.

  In the first embodiment, as shown in FIG. 10, the narrow portion 92 has a width L 1 of the narrowest portion (downstream end) 92 b of the narrow portion 92 relative to the filter chamber 94 and the filters 96 and 97. , 97 are set shorter than the length L2 in the longitudinal direction (left-right direction). And as shown in FIG. 10, the constriction part 92 is arrange | positioned with respect to the length direction of the filters 96 and 97 on the right side, ie, the upstream of the removal direction of the filters 96 and 97. As shown in FIG. Therefore, the narrowed portion 92 is disposed on the back side with respect to the attachment / detachment port 94 b of the filters 96 and 97.

An air collection unit 98 is connected to the downstream side of the filter chamber 94 with respect to the exhaust direction Ya. The air collecting portion 98 is formed such that the flow path 98 a is narrowed as it goes downstream. Therefore, the exhaust gas having passed through the filters 96 and 97 is collected as it goes downstream.
A centrifugal fan 99 as an example of an exhaust member is disposed downstream of the air collection unit 98. The centrifugal fan 99 sucks in the gas of the air collection unit 98 and exhausts it toward the left. On the left side of the centrifugal fan 99, a discharge unit 101 connected to the outer surface of the apparatus main body 1a of the image forming apparatus 1 as an example of a housing is connected.
The exhaust devices 89 to 101 of the first embodiment are configured by the members given the reference numerals 89 to 101.

(Operation of Example 1)
In the image forming apparatus 1 of the first embodiment having the above configuration, the centrifugal fan 99 operates at the time of image formation, and the gas in the vicinity of the fixing device 40 and the curl correction device 60 is sucked and exhausted. The exhaust gas including UFP and floating toner in the vicinity of the fixing device 40 passes through the clean flow unit 91, passes through the filters 96 and 97, and is cleaned and exhausted.
Here, in the clean flow portion 91 of the first embodiment, the narrowed portion 92 is disposed on the upstream side, and the enlarged portion 93 is disposed on the downstream side.

If the flow path of the exhaust is formed to have the same width as the width of the filters 96 and 97 without having the narrowed portion 92 and the enlarged portion 93, that is, if exhaust is sent to the filter from a cylindrical flow path having a constant cross section, It is necessary to secure a large space for the exhaust flow path. Therefore, there is a problem that the size of the image forming apparatus 1 is increased.
In the configuration described in Patent Document 1, it is necessary to separate two filters from each other or to form the bypass portion at a separate position, and the space required as a whole is large, and there is a problem of enlargement. In addition, even in the configuration described in Patent Document 2, there is a problem of increasing the size because the route is branched and then merged to require a space for arranging the route.

  In the configuration having no constriction portion 92 and having only an enlarged portion in which the flow path expands from the cylindrical flow path toward the width of the filter, the gas flow in the upstream duct portion before the flow path is expanded Turbulence and vortices may occur, and it is difficult for turbulence to spread in the expansion part. Therefore, the exhaust gas is blown to only a specific part of the filter. Therefore, only a part of the filter is preferentially soiled, and the portion which is difficult to be sprayed is hardly soiled. Therefore, the variation in the degree of contamination is likely to occur in the longitudinal direction of the filter. In this state, at the time of filter replacement, an almost unused portion of the filter is discarded, resulting in waste of resources.

On the other hand, in the first embodiment, the narrowed portion 92 is disposed upstream of the enlarged portion 93. Therefore, when passing through the narrowed portion 92, the gas is squeezed. Therefore, even when the turbulent flow gas passes through the narrowed portion 92 while passing through the exhaust duct 90, the turbulent flow is easily settled while passing through the narrowing flow path 92a. Therefore, when the turbulent flow is reduced, the gas which has reached the enlarged portion 93 flows more easily along the wall surface than the turbulent flow, and is easily expanded along the enlarged portion 93.
Therefore, the exhaust gas can be more easily blown to the entire area in the longitudinal direction of the filters 96 and 97 as compared to the case where the narrowed portion 92 is not provided. Therefore, the variation in the degree of contamination is suppressed in the longitudinal direction of the filters 96 and 97. Thus, the exhaust gas is cleaned using the entire longitudinal direction of the filters 96, 97.

Further, in the first embodiment, the flow path 93 a is expanded at the enlarged portion 93 on the upstream side of the filters 96 and 97. As the flow path 93a expands, the flow velocity of the gas decreases. In general, if the air volume is the same, UPO and the like can be more easily collected by the filters 96 and 97 when the flow velocity is lower than when the flow velocity is high. Therefore, in the first embodiment, the collection performance of the filters 96 and 97 can be improved as compared with the case where the flow velocity of the exhaust gas sent to the filters 96 and 97 does not decrease.
In particular, in the first embodiment, the UFP filter 96 having a large pressure loss is disposed on the upstream side. Therefore, the UFP filter 96 is difficult to pass gas, and as a result, the gas flow rate tends to be low. Therefore, in the first embodiment, in addition to the decrease in the flow velocity in the enlarged portion 93, the flow velocity is also reduced in the UFP filter 96, and the collection performance of the filters 96 and 97 as a whole tends to be improved.

  Furthermore, in the first embodiment, the UFP filter 96 is disposed upstream of the activated carbon filter 97. When the activated carbon filter 97 is disposed on the upstream side, the activated carbon filter 97 also collects UFP and the like, and as a result, the life of the activated carbon filter 97 is shortened. On the other hand, in the first embodiment, the UFP filter 96 is disposed on the upstream side, the UFP, paper dust and the like are removed first, and the gas from which the UFP and the like are removed is passed through the activated carbon filter 97. Therefore, it is possible to prolong the life of the filters 96 and 97 as a whole.

In the first embodiment, the narrowed portion 92 is disposed on the upstream side in the removal direction of the filters 96 and 97. Although the variation in the degree of contamination is suppressed in the width direction of the filters 96 and 97 at the narrowed portion 92 and the enlarged portion 93, the downstream side of the narrowed portion 92 in the exhaust direction Ya is most likely to be contaminated.
If the most dirty part is on the near side when taking out the filters 96 and 97, the most dirty part is pulled out immediately after the start of taking it out and exposed to the outside during the drawing operation. Therefore, floating toner and the like are easily released or leaked from the filters 96 and 97. On the other hand, in the first embodiment, the most soiled portion is on the back side in the takeout direction, and the time of exposure to the outside is shorter than when it is on the front side. Therefore, the leakage of the floating toner is suppressed, and the contamination of the image forming apparatus 1 and the surrounding floor or room is reduced.

(Modification example)
As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various change is made in the range of the summary of this invention described in the claim. Is possible. Modifications (H01) to (H05) of the present invention are exemplified below.
(H01) In the above embodiment, the configuration of the image forming apparatus 1 as an example of the image forming apparatus has been exemplified, but the present invention is not limited to this. The present invention can be applied to a printer, a fax machine, or a multifunction peripheral having a plurality of functions. Further, the present invention is not limited to an image forming apparatus for multicolor development, and can be configured with a single-color, so-called monochrome image forming apparatus, and is not limited to a so-called tandem type image forming apparatus. Is also applicable.

(H02) The above embodiment is also applicable to the configuration without the curl correction device 60.
(H03) In the above embodiment, the exhaust device for cleaning and exhausting the air in the vicinity of the fixing device 40 and the curl correcting device 60 has been exemplified, but the invention is not limited thereto. The present invention can be applied to an exhaust device for exhausting air in the vicinity of the charging device or an exhaust device for exhausting air in the vicinity of the developing device, etc.

(H04) In the above embodiment, the enlargement unit 93 exemplifies a configuration in which both the longitudinal direction and the latitudinal direction of the filters 96 and 97 are enlarged, but the invention is not limited thereto. As the longitudinal enlargement is particularly important, it is possible to have a configuration in which the short direction does not extend. In the lateral direction, the same configuration as the enlargement or the length is desirable, but it is also possible to make the shape to be narrowed. Further, in the embodiment, the narrowing portion 92 is illustrated as being narrowed only in the longitudinal direction, but it is also possible to be narrowed in the short direction. In addition, although it is desirable that the constriction portion 92 be narrowed in the lateral direction or have the same length, it may be configured to expand in the lateral direction.

(H05) In the above embodiment, the configuration in which two filters 96 and 97 are used is illustrated, but is not limited thereto. The number of filters may be only one, or three or more, depending on the application, required cleanliness of exhaust, design, specifications and the like. Also, the type of filter can be changed according to the application and the like. Furthermore, although it is desirable to arrange in order of large pressure loss, it is also possible to arrange regardless of pressure loss. However, if a longer life is placed upstream and a shorter life is placed downstream, the partially cleaned gas that is the upstream filter will flow through the downstream filter, and the life as a whole It is possible to make the

1 ... image forming apparatus 1a ... housing,
5 ... medium,
11 ... Image holder,
15 + 20 ... Transfer device,
40: Fixing device,
89 to 101: Exhaust system,
91: Clear stream part,
92 ... constriction,
92a, 93a, 94, 98a, 101...
93 ... enlarged part,
96 ... first collection member,
96, 97 ... collecting member,
97 ... second collection member,
99 ... Exhaust member,
L1 ... width of narrowest part of constriction,
L2: Length in the longitudinal direction of the collecting member,
Ya ... exhaust direction.

Claims (8)

And
An exhaust member for exhausting the gas inside the housing to the outside;
A collection member disposed in the middle of the gas flow path for collecting dust in the gas;
A narrowed portion disposed upstream of the collection member with respect to the gas exhaust direction and narrowing the flow path toward the downstream, and a downstream portion disposed downstream of the narrowed portion and going downstream And an enlarged portion for expanding the flow path, and the narrowest portion of the narrowed portion has a width of the clean flow portion shorter than the length of the collection member in the longitudinal direction,
An exhaust system characterized by comprising. The collection member having a first collection member, and a second collection member disposed downstream of the first collection member in the exhaust direction,
The exhaust system according to claim 1, comprising: The first collection member is disposed on the upstream side in the exhaust direction, and the second collection member having a lower pressure loss than the first collection member is disposed on the downstream side. Exhaust system. The collection member detachably supported on the housing,
The exhaust system according to any one of claims 1 to 3, further comprising: The narrowed portion disposed upstream of the removal direction of the collection member,
The exhaust system according to claim 4, further comprising: The exhaust apparatus according to any one of claims 1 to 5, wherein the size of the flow passage in the short direction of the collection member is also wide corresponding to the enlarged portion. An image carrier,
A transfer device for transferring an image formed on the image carrier to a medium;
A fixing device for fixing an image transferred to a medium;
The exhaust system according to any one of claims 1 to 6, wherein the gas inside the image forming apparatus is exhausted to the outside.
An image forming apparatus comprising: The exhaust device for exhausting the gas from the fixing device;
The image forming apparatus according to claim 7, comprising:

Images