JP2015081933A - Intake pipe, intake device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake pipe, or the like, having a passage section with a passage space formed by connecting an inlet arranged facing a longitudinal part of a structure which needs to introduce air to suck the air and an outlet having an opening different in shape from the inlet, to cause the air to pass through, while preventing the air from being introduced in non-uniform intake speed distribution in the longitudinal direction of the inlet.SOLUTION: An intake pipe includes: an inlet having an opening which is long in one direction parallel to a longitudinal part of a structure which is long in one direction, and arranged facing the longitudinal part of the structure to introduce air; an outlet having an opening different in shape from the inlet, and discharging the air introduced through the inlet; a passage section with a passage space formed by connecting the inlet and the outlet to cause the air to pass through; and a plurality of control sections arranged in different sections in the passage space of the passage section in an air flowing direction, to control the flow of the air.

Description

  The present invention relates to an intake pipe, an intake device, and an image forming apparatus.

Conventionally, the present applicant has proposed an image forming apparatus provided with a suction (suction) device described below (Patent Document 1).
That is, the suction device in the image forming apparatus includes a duct having a suction port facing the photoconductor and a blower means for sucking air through the duct on the downstream side of the photoconductor of the developing machine. Changing means for changing the wind speed distribution in the photosensitive member axial direction is provided. Patent Document 1 discloses that according to this image forming apparatus, the suction device can efficiently suck and remove the toner cloud from the developing machine to prevent contamination inside the machine.

Japanese Patent Laid-Open No. 10-20723

  The present invention has an opening shape that is long in one direction parallel to the longitudinal portion of the target structure that requires air suction, and is disposed in a state facing the longitudinal portion of the target structure. An intake port for suction, an exhaust port that has an opening shape different from that of the intake port, and sucks out the sucked air, and a passage part in which a passage space for flowing air is formed by connecting between the intake port and the exhaust port. Provided as an intake pipe provided is an intake pipe capable of suppressing the distribution of the air suction speed in the longitudinal direction of the intake port from being shifted, and an intake device and an image forming apparatus using the intake pipe. Is.

The intake pipe of the present invention (A1)
It has a long opening shape in one direction parallel to a long longitudinal portion in one direction of the target structure requiring air suction, and is arranged in a state facing the longitudinal portion of the target structure to suck in air The air inlet,
An exhaust port that has an opening shape different from that of the intake port, and sucks out air sucked from the intake port;
A passage portion formed with a passage space for flowing air by connecting between the intake port and the exhaust port;
It is provided in the site | part which is different in the direction which flows the air of the channel | path space of the said channel | path part, and is provided with the some suppression part which suppresses the flow of air.

  The intake pipe of this invention (A2) is the intake pipe of the above invention A1, wherein the most upstream suppressing portion provided in the upstream portion of the plurality of suppressing portions in the direction of flowing air in the passage space of the passage portion, The passage space in the most upstream part is formed so as to be closed by a breathable member.

  The intake pipe of the present invention (A3) is the intake pipe of the above-described invention A2, wherein the most upstream suppressing portion is formed so as to block the intake port with the air-permeable member.

  The intake pipe of this invention (A4) is the intake pipe of the above-mentioned invention A2 or A3, the downstream of the most upstream suppression part in the direction of flowing air in the passage space of the passage part among the plurality of suppression parts. At least one of the one or a plurality of restraining portions provided in the part is configured in a form having a gap extending in a direction parallel to the longitudinal direction of the opening shape of the intake port in the passage space It is.

  The intake pipe of the present invention (A5) is the intake pipe of the above-described invention A4, wherein the passage section has a bent passage section after the direction in which air flows is bent, and the suppressing section having the gap is the bent section. It is provided in the required site | part of the channel | path space of a channel | path part.

  The intake device of the present invention (B1) includes a suction device for sucking air and an intake pipe having an exhaust port connected to the suction machine, and the intake pipe is the intake pipe of any one of the inventions A1 to A5. It is characterized by being.

  The air intake device of this invention (B2) is the air intake device of the above invention B1, wherein the target structure is at least one of a corona discharger, a developing device, and an image carrier.

The image forming apparatus according to the present invention (C1) further includes a target structure that needs to suck air, and an intake device that sucks air existing in the target structure.
The intake device is the intake device of the invention B1.

  The image forming apparatus according to the invention (C2) is the image forming apparatus according to the invention C1, wherein the target structure is at least one of a corona discharger, a developing device, and an image carrier.

  According to the intake pipe of the invention A1, the distribution of the air suction speed in the longitudinal direction of the intake port compared to an intake pipe that does not have a protruding portion in the passage space through which air sucked from the intake port flows to the exhaust port Can be prevented from being in a state of being offset.

  In the intake pipe of the invention A2, the distribution of the air suction speed in the longitudinal direction of the intake port is easily shifted compared to the case where the most upstream suppressing portion is not closed by the air-permeable member. Can be suppressed.

  In the intake pipe of the invention A3, the distribution of the air suction speed in the longitudinal direction of the intake port is more deviated than in the case where the most upstream suppressing portion is not in a state where the ventilation port is closed with a breathable member. This can be easily suppressed.

  In the intake pipe of the above invention A4, the distribution of the air suction speed in the longitudinal direction of the intake port is deviated compared to the case where no suppression portion having a gap is provided as one of the suppression portions other than the most upstream suppression portion. It can suppress more reliably that it will be in a state.

  In the intake pipe of the above invention A5, the distribution of the air suction speed in the longitudinal direction of the intake port is shifted as compared with the case where the suppressing portion having a gap is not provided in the required portion of the bent passage portion. Can be suppressed more reliably.

  According to the intake device of the above invention B1, the distribution of the air suction speed in the longitudinal direction of the intake port in the intake pipe can be suppressed from being shifted, and the amount of air with less unevenness can be suppressed over the entire region in the longitudinal direction of the intake port. Inhalation is performed.

  In the air intake device of the invention B2, in the case of any of the corona discharger, the developing device, and the image carrier, the unevenness in the longitudinal direction of the air intake port with respect to the respective portions in the longitudinal direction that require suction of the air. Less air can be drawn.

  According to the image forming apparatus of the invention C1, the air can be sucked into the target structure with less unevenness over the entire area of the intake pipe in the longitudinal direction of the intake port.

  In the image forming apparatus according to the invention C2, in the case of any one of the corona discharger, the developing device, and the image carrier, the longitudinal direction that requires suction of the air is required as compared with the case where the configuration of the invention is not provided. The air can be sucked into each portion with little unevenness in the longitudinal direction of the intake port.

FIG. 2 is an explanatory diagram showing an outline of an image forming apparatus using an intake device (including an intake duct) according to Embodiment 1 and the like. FIG. 2 is a perspective view illustrating a main part (such as an image forming unit to which an intake device is applied) of the image forming apparatus in FIG. 1. It is a perspective view which shows the outline | summary of the pre-transfer corona discharger of the air intake apparatus with which the image forming apparatus of FIG. 1 is equipped, and the structure used as the object of the air intake. It is the schematic which shows a state when the air intake apparatus of FIG. 3 is seen from upper direction. FIG. 4 is a cross-sectional explanatory view taken along line QQ of the intake device (intake duct) and the pre-transfer corona discharger of FIG. 3. It is the schematic which shows a state when it sees from the inlet side of the intake duct in the intake device of FIG. FIG. 4 is an explanatory diagram schematically showing the air flow direction and state in the intake duct of FIG. 3 when viewed from above. FIG. 6 is an explanatory diagram schematically showing the air flow direction and state in the intake duct of FIG. 3 when viewed in the cross-sectional state shown in FIG. 5. It is a graph which shows the result of the simulation which analyzed the state of the wind speed (distribution) in the inlet port of the intake duct of FIG. FIG. 6 is a cross-sectional explanatory view mainly showing the intake duct of the intake device according to Embodiment 2 following FIG. 5. It is explanatory drawing typically shown in the state when the air flow direction and state in the intake duct of FIG. 10 are seen in the cross-sectional state shown in FIG. It is upper surface explanatory drawing which shows another example of an intake duct. An example of the intake duct as a comparative example is shown, (a) is a perspective view showing the intake duct, and (b) is a cross-sectional view taken along line QQ of (a). It is a graph which shows the result of the simulation which analyzed the state of the wind speed (distribution) in the inlet port of the intake duct of FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (simply referred to as “embodiments”) will be described with reference to the accompanying drawings.

[Embodiment 1]
1 to 6 show an intake pipe, an intake device using the intake pipe, and an image forming apparatus according to the first embodiment. FIG. 1 shows an outline of the image forming apparatus, FIG. 2 shows a main part of the image forming apparatus (such as an image forming unit including an intake device), and FIG. 3 shows the intake device (including an intake pipe) and the intake air. 4 shows a corona discharger that is an example of a long target structure that requires air suction by the device, FIG. 4 shows a state when the intake device of FIG. 3 is viewed from above, and FIG. FIG. 6 shows a state of a cross section taken along line Q-Q of the intake device (intake pipe and corona discharger), and FIG. 6 shows a state when the intake port in the intake pipe of FIG. 3 is mainly viewed. The arrows indicated by reference signs X, Y, and Z in the drawings are orthogonal coordinate axes (directions) indicating the respective directions of the width, height, and depth of the three-dimensional space assumed in each drawing.

  The image forming apparatus 1 according to the first embodiment is configured as a color printer, for example. As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 10 that forms a toner image composed of toner as a developer in a housing 100 composed of a support frame, an exterior cover, and the like. An intermediate transfer unit 20 that holds the toner image formed by the image forming unit 10 by primary transfer and then performs secondary transfer onto a recording sheet 9 as an example of a recording material; and a secondary transfer position of the intermediate transfer unit 20 A paper feeding device 30 that accommodates and transports the required recording paper 9 to be supplied, and a fixing device 40 that fixes the toner image on the recording paper 9 on which the toner image has been transferred by the intermediate transfer unit 20 is disposed. doing. A one-dot chain line in FIG. 1 indicates a main conveyance path of the recording paper 9.

  The image forming unit 10 includes four image forming units 10Y, 10M, and 10C that respectively form toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (black: K). , 10K. The four image forming devices 10 (Y, M, C, K) are arranged in a state of being arranged in series in the internal space of the housing 100. Further, the image forming apparatuses 10 (Y, M, C, K) have substantially the same configuration as shown below.

That is, each image forming unit 10 (Y, M, C, K) is configured using, for example, a known electrophotographic system, and as shown in FIGS. 1 and 2, the direction indicated by the arrow. A photosensitive drum 11 rotating in the clockwise direction in the drawing is provided, and the following devices are mainly arranged around the photosensitive drum 11.
The main devices are a charging device 12 for charging an image holding surface (outer peripheral surface) capable of forming an image on the photosensitive drum 11 to a required potential, and image information (signal) on the charged outer peripheral surface of the photosensitive drum 11. And an exposure device 13 (Y, M, C, K) that forms an electrostatic latent image (for each color) having a potential difference by irradiating light based on the above and a corresponding color (Y, M, A developing device 14 (Y, M, C, K) that develops a toner image that is a visible image by developing with toner as a developer of (C, K), and an intermediate transfer unit 20 (intermediate transfer of the toner image) A charge-adjusting corona discharger 16 that adjusts the state of charging, including toner and other deposits that remain on the image holding surface of the photosensitive drum 11 after the primary transfer to the belt), and a charge-adjusting corona discharger 16. Of toner or the like that passes through the toner and adheres to the image holding surface of the photosensitive drum 11 A drum cleaning device 17 for cleaning by removing a charge eliminator 18, etc. which neutralizes the image holding surface of the photosensitive drum 11 after cleaning.

  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 columnar substrate to be grounded. It receives power and rotates in the direction indicated by the arrow. The charging device 12 is a non-contact type charging device in which a charging bias is applied to a discharge wire disposed in a state where a predetermined interval is provided on the image holding surface of the photosensitive drum 11 and charging is performed by corona discharge. As the charging device 12 in the first embodiment, two discharge wires 12b and 12c are stretched inside a long box-shaped shield case (cover member) 12a along the axial direction of the photosensitive drum 11, and the shield case A so-called scoroton type corona discharge device in which a charge adjusting material is arranged in an opening facing the photosensitive drum 11 of 12a is used. As the charging bias, when the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device is supplied.

  The exposure device 13 (Y, M, C, K) is an image of the photosensitive drum 11 after the light Bm (dotted line with arrows) configured according to the image information input to the image forming apparatus 1 is charged. An electrostatic latent image is formed by irradiating the holding surface. As the exposure device 13, a non-scanning type exposure device configured using a light emitting diode and an optical component or a scanning type configured using an optical component such as a semiconductor laser and a polygon mirror is used. The developing device 14 (Y, M, C, K) uses, for example, a two-component developer containing toner and carrier. As shown in FIG. 2, the developing device 14 (Y, M, C, K) is a screw auger that supplies a two-component developer of any one of the four colors contained in a container-like housing 14a. Are agitated by the agitating and conveying members 14b and 14c, and are frictionally charged to a required polarity, and then are supplied to the developing zone 14d that is rotated by the developing roller 14d that is rotated by being supplied with a developing bias, The latent image formed on the photosensitive drum 11 is developed.

  As shown in FIG. 2, FIG. 3, and the like, the charging adjustment corona discharger 16 has a long box shape along the axial direction of the photosensitive drum 11, and a portion facing the photosensitive drum 11 is opened in a long and narrow rectangular shape (16b). ) Formed in a shield case (covering member) 16a and a discharge wire 16c stretched in an inner space of the shield case 16a in a state substantially parallel to the axial direction of the photosensitive drum 11. An elongated rectangular opening 16d substantially parallel to the axial direction of the photosensitive drum 11 (corresponding to a long longitudinal direction B) is formed on the end surface of the shield case 16a opposite to the portion facing the photosensitive drum 11. Has been. The opening 16d is for use when air is sucked by the intake device 5. Note that a bias for charge adjustment is supplied to the discharge wire 16c when an image is formed. Further, the corona discharger 16 for charge adjustment can be used together with the charging device 12 as a second charging device that charges the image holding surface of the photosensitive drum 11.

  The drum cleaning device 16 includes a container-shaped housing 16 a, a rotating brush 16 b that rotates in a state where a hair material is in contact with the outer peripheral surface of the photosensitive drum 11 after the primary transfer, and a rotating brush 16 b on the outer peripheral surface of the photosensitive drum 11. The cleaning plate 16c is disposed so as to come into contact with the required pressure at a position downstream of the contact portion with the required pressure and scrapes off adhering matter such as toner that adheres and adheres to the hair material of the rotating brush 16. A flicker 16d for scraping off the adhering matter such as toner, and a recovery transporting member 16e such as a screw auger for recovering the toner scraped off from the hair material of the rotating brush 16 and transporting it to a recovery system (not shown). Yes. As the cleaning plate 16c, a plate-like member made of flexible rubber, resin or the like is used.

  As shown in FIG. 1 and the like, the intermediate transfer unit 20 is disposed so as to exist at a position below each image forming unit 10 (Y, M, C, K). The intermediate transfer unit 20 rotates in a direction indicated by an arrow while passing through a portion serving as a primary transfer position (a portion before passing through the developing device 14 and reaching the corona discharger 16 for charging adjustment) on the photosensitive drum 11. (Moving) intermediate transfer belt 21, a plurality of support rolls 22 a to 22 d that hold the intermediate transfer belt 21 in a desired state from its inner surface, and rotatably support the intermediate transfer belt 21 in each image forming unit 10. A primary transfer device 23 that primarily transfers a toner image to the intermediate transfer belt 21 while being pressed and rotated against a portion serving as a primary transfer position of the photosensitive drum 11, and an outer surface (image) of the intermediate transfer belt 21 supported by a support roll 22e. A secondary transfer device 25 that rotates in contact with the holding surface) at a predetermined pressure, and on the outer surface of the intermediate transfer belt 21 after passing through the secondary transfer device 25. Toner adhering to distillation, is mainly constituted by a belt cleaning device 26 that cleans by removing deposits such as paper dust.

  Among the plurality of support rolls 22a to 22f that support the intermediate transfer belt 21, the support roll 22a is configured as a drive roll, the support roll 22c is configured as a tension applying roll, and the support roll 22e is configured as a secondary transfer auxiliary roll. The primary transfer device 23 is a contact-type transfer device including a primary transfer roll that rotates in contact with the inner surface of the intermediate transfer belt 21 and is supplied with a primary transfer bias. As the primary transfer bias, a DC voltage or the like having a polarity opposite to the charging polarity of the developer is supplied. The secondary transfer device 25 is a contact-type transfer device including a secondary transfer roll that rotates in contact with the outer surface of the intermediate transfer belt 21 and is supplied with a secondary transfer bias. As the secondary transfer bias, a DC voltage or the like having a polarity opposite to the charging polarity of the developer is supplied. The belt cleaning device 26 has substantially the same configuration as the drum cleaning device 17. In FIG. 1, reference numeral 26 a denotes a housing of the belt cleaning device 26, 26 b denotes a rotating brush, 26 c denotes a cleaning plate, and 26 e denotes a collection conveyance member.

  The sheet feeding device 30 is disposed so as to exist at a position below the intermediate transfer unit 20. The paper feeding device 30 is a single (or plural) paper container 31 that accommodates recording papers 9 of a desired size and type, and sends out the recording papers 9 one by one from the paper container 31. The apparatus 32 is mainly configured. The fixing device 40 rotates inside the housing 41 in a direction indicated by an arrow and is heated by heating means so that the surface temperature is maintained at a predetermined temperature, and the heating rotator 42 A pressurizing rotator 43 that rotates in contact with a predetermined pressure in a state substantially along the axial direction is disposed.

  In addition, the housing 100 of the image forming apparatus 1 is provided between the paper feeding device 30 and the secondary transfer position of the intermediate transfer unit 20 (the portion where the intermediate transfer belt 21 and the secondary transfer device 25 are in contact). A plurality of paper conveyance roll pairs 33a, 33b, 33c,... And a conveyance conveyance path composed of a conveyance guide material are provided. Further, between the secondary transfer device 25 and the fixing device 40, a belt type paper transporting device 34 for transporting the recording paper 9 after the secondary transfer to the fixing device 40 is installed. Further, on the discharge side of the fixing device 40, a discharge conveyance path including a plurality of conveyance roll pairs 45a and 45b and a conveyance guide material is provided. In addition, a discharge storage section (not shown) that stores the recording paper 9 after image formation discharged from the discharge conveyance path is provided in a part such as the outside of the housing 100.

  Image formation by the image forming apparatus 1 is performed as follows. Here, a basic image forming operation when forming a full-color image formed by combining the four color (Y, M, C, K) toners on one side of the recording paper 9 will be described as an example.

  In the image forming apparatus 1, when there is an instruction to start an image forming operation (printing), in each of the four image forming units 10 (Y, M, C, K), first, each photosensitive drum 11 rotates in the direction of the arrow. Each charging device 12 charges the image holding surface of each photosensitive drum 11 to a required polarity and potential. Subsequently, the exposure device 13 is based on the image data separated into the color components (Y, M, C, K) transmitted from the image processing device (not shown) on the image holding surface of the charged photosensitive drum 11. Exposure is performed by irradiating emitted light Bm, and electrostatic latent images of respective color components each having a required potential difference are formed. Subsequently, each developing device 14 (Y, M, C, K) has each color (Y, M, C) charged to a required polarity with respect to the electrostatic latent image of each color component formed on each photosensitive drum 11. , K) is supplied to each of the two components to electrostatically attach the toner. As a result, one of four color (Y, M, C, K) toner images is formed on the image holding surface of the photosensitive drum 11 in each image forming unit 11.

  Next, each color toner image formed on each photosensitive drum 11 of each image forming unit 10 (Y, M, C, K) is rotated in the direction of the arrow by each primary transfer device 23 of the intermediate transfer unit 20. Primary transfer is performed so as to overlap the outer surface of the transfer belt 21 in order. After the primary transfer is completed, the photosensitive drum 11 is easily cleaned by the corona discharge in the charge adjustment corona discharger 16 so that the potential of the deposit remaining on the image holding surface and the potential of the image holding surface are easily cleaned. The charge potential is adjusted. The photosensitive drum 11 after passing through the charging adjustment corona discharger 16 is cleaned by the drum cleaning device 17 and then the image holding surface is discharged by the charge eliminator 18, thereby preparing for the next image forming step.

  Subsequently, in the intermediate transfer unit 20, the toner image primarily transferred to the intermediate transfer belt 21 is held and transported to the secondary transfer position, and then transported to the secondary transfer position from the paper feeding device 30 through the supply transport path. The toner image on the intermediate transfer belt 21 is secondarily transferred to the recording paper 9 by the secondary transfer device 25 at once. After the secondary transfer is completed, the outer surface of the intermediate transfer belt 21 is cleaned by the belt cleaning device 26 to prepare for the next intermediate transfer step.

  Finally, the recording paper 9 onto which the toner image has been secondarily transferred is peeled off from the intermediate transfer belt 21 and then transported by the paper transporting device 34 and introduced into the fixing device 40, where necessary fixing processing ( The toner image is fixed in response to heat and pressure. The recording paper 9 after the fixing is completed is discharged to the outside of the housing 100 through the discharge conveyance path and stored in the discharge storage portion in the image forming operation only for forming an image on one side.

  With the above operation, the image forming apparatus 1 outputs the recording paper 9 on which a full color image formed by combining the four color (Y, M, C, K) toner images is formed. When there is an instruction for a plurality of image forming operations, the above-described series of operations are similarly repeated for the number of sheets.

  In this image forming apparatus 1, ozone generated by corona discharge of the corona discharger 16 for charging adjustment and discharge products thereof adhere to and accumulate on the photosensitive drum 11 to induce image defects (mainly density unevenness). In order to prevent this, as shown in FIG. 2, the air existing inside or around the shield case 16a of the charging adjustment corona discharger 16 is sucked (sucked) together with its ozone and discharge products. An intake device 5 is installed. Details of the intake device 5 will be described later.

  By the way, in this image forming apparatus 1, ozone generated by corona discharge of the charging device 12 and discharge products thereof adhere to the discharge wires 12b and 12c and the photosensitive drum 11 and accumulate, thereby causing a charging failure (mainly uneven charging). In order to prevent image defects (mainly image quality irregularities), as shown in FIG. 2, air blown from a blower (not shown) into the shield case 12a of the charging device 12 (two-dot chain arrows) ) And ozone and its discharge products are discharged from the inside of the shield case 12a.

  Further, in this image forming apparatus 1, the photosensitive drum is sandwiched between the developing roll 14d in order to suck and capture ozone and discharge products discharged from the charging device 12 by the air blowing, or in the developing process of the developing device 14. As shown in FIG. 2, in order to suck and capture toner floating or leaking in a region before and after 11, a portion on both the upstream side and the downstream side in the rotational direction with the developing device 14 sandwiched between them. Suction devices 80A and 80B are arranged for sucking and capturing the ozone, discharge products, and unnecessary toner respectively.

The suction device 80 </ b> A includes a first suction duct 81 having a first suction port 82 facing a portion between the charging device 12 and the developing device 14 on the image holding surface of the photosensitive drum 11, and a first suction of the photosensitive drum 11. A combination of a second suction duct 83 having a second suction port 84 facing a portion between the port 82 and the developing device 14 is provided, and the exhaust ports of the suction ducts 83 are used as a common exhaust port 85. In addition, the common exhaust port 85 is connected to a suction means such as an intake fan (not shown) by piping. The suction device 80A sucks ozone and discharge products discharged from the charging device 12 into the first suction duct 81 as indicated by a two-dot chain line arrow from the first suction port 82, and floats or leaks toner. Is sucked into the second suction duct 83 from the second suction port 84 as indicated by a two-dot chain line arrow, and the air sucked into the suction ducts 81 and 83 is discharged from the common exhaust port 85.
Further, the suction device 80B includes a third suction duct 86 having a third suction port 87 that faces a portion of the image holding surface of the photosensitive drum 11 that passes through the developing device 14 and reaches the primary transfer position. The exhaust port 87 of the suction duct 86 is connected to suction means (not shown) by piping. The difference in suction 80B is that unnecessary toner leaking from the developing device 14 or the like is sucked into the third suction duct 86 from the third suction port 87 as indicated by the two-dot chain line arrow, and the air sucked into the suction duct 86 is removed. The air is discharged from the exhaust port 87.
Ozone, discharge products, toner, and the like discharged from the common exhaust port 85 and the exhaust port 87 are captured by a capturing unit such as a filter disposed on the way to or through the suction unit. Note that the suction means in the two suction devices 80A and 80B are combined into one, for example.

<Intake device>
Next, the intake device 5 will be described.

  As shown in FIGS. 2, 3 and the like, the intake device 5 includes a suction device 50 having a rotary fan or the like for sucking air, and a corona discharge for charge adjustment that is connected to the suction device 50 and requires suction of air. A suction duct 51 is provided for sucking and discharging the air present in and around the electric appliance 16.

  The suction machine 50 is driven and controlled so as to suck in a required amount of air. As such a suction machine 50, what is comprised using various blowers, such as centrifugal blowers, such as a sirocco fan, a crossflow fan, an axial flow fan, is used, for example. The suction device 50 has a structure that discharges sucked air or the like to the outside of the housing 100 of the image forming apparatus 1. Furthermore, capture means such as a filter for capturing unwanted matter mixed with the air to be sucked is disposed at the intake side position, the exhaust side position, or both positions of the suction device 50.

  On the other hand, as shown in FIGS. 3 to 6 and the like, the intake duct 51 is a portion in the longitudinal direction B of the charging adjustment corona discharger 16 to which air is sucked (opening 16d on the back plate of the shield case 16a). Are connected to the suction device 50 and connected to the suction device 50 and connected between the intake port 52 and the exhaust port 53. And a passage portion (main body portion) 54 in which a passage space 54a for flowing air is formed. In the intake device 5 according to Embodiment 1, since the intake port 52 of the intake duct 51 is physically separated from the corona discharger 16 for charge adjustment, the intake port 52 and the opening of the shield case 16a of the corona discharger 16 are provided. The connection duct 56 is connected to 16d.

  The passage portion 54 of the intake duct 51 includes an exhaust passage portion 54A, a first bent passage portion 54B, and a second bent passage portion 54C, as shown in FIGS.

  One end of the exhaust passage portion 54A is opened by providing an exhaust port 53, the other end is closed, and the whole is formed so as to extend along the longitudinal direction B of the charging adjustment corona discharger 16. It is a cylindrical passage part. The first bent passage portion 54B is substantially perpendicular to the lower portion (in the direction substantially parallel to the coordinate axis Y) in a state where the width of the passage space 54a is widened from a portion (midway) near the other end of the exhaust passage portion 54A. It is a cylindrical passage portion formed to be bent and extend. The second bending passage portion 54C is bent in a horizontal direction (a direction substantially parallel to the coordinate axis X) from one end portion of the first bending passage portion 54B with the same width of the passage space, and is charged in the corona discharger 16 for charge adjustment. It is the cylindrical channel | path part formed so that it might extend toward.

  The passage spaces 54a of the first bending passage portion 54B and the second bending passage portion 54C are set to have substantially the same width (dimension along the longitudinal direction B). A vent 52 is formed at the end of the second bent passage portion 54C. The intake port 52 is formed as an opening having a rectangular opening shape that is slightly narrower than the cross-sectional shape of the passage space at one end portion (terminal portion) of the second bent passage portion 54C (however, in the longitudinal direction of the intake port 52) The length is substantially the same as the width of the second bent passage portion 54C).

  The intake port 51 of the intake duct 51 is formed so that the opening shape thereof is a long opening shape (for example, a rectangle) parallel to the longitudinal direction B portion (opening 16d) of the charging adjustment corona discharger 16. On the other hand, the exhaust port 53 is formed so that the opening shape is substantially square. Connected to the exhaust port 53 is a connection duct 55 that is connected to the suction device 50 and sucks air from the exhaust port 53 by exerting the suction force of the suction device 50 (FIGS. 3 and 4).

  For this reason, the intake duct 51 has a relationship in which the intake port 52 and the exhaust port 53 are formed in different opening shapes. However, even when the intake port 52 and the exhaust port 53 have the same shape, when the opening areas are different from each other (when they have similar shapes), the relationship is that they are formed with different opening shapes. Shall be included. Further, as shown in FIGS. 3, 4, etc., the exhaust port 53 protrudes by a required dimension G outside the one end portion 53 a in the longitudinal direction B of the intake port 53 having a rectangular opening shape. It is formed in the state to do.

By the way, in the intake duct 51 having the intake ports 52 and the exhaust ports 53 having different opening shapes, the cross-sectional shape of the passage space 54a is changed in the middle of the passage portion 54 connecting the intake ports 52 and the exhaust ports 53. There will be a part.
In the intake duct 51 according to the first embodiment, the opening shape of the intake port 52 is rectangular, whereas the opening shape of the exhaust port 53 is square and different from each other. 54a) are present (actually, the first bent passage portion 54B and the second bent passage portion 54C). As a result, in the intake duct 51, in particular, the cross-sectional shape of the passage space 54a in the exhaust passage portion 54A is substantially square, whereas the cross-section of the passage space 54a in the first bent passage portion 54A and the second bent passage portion 54C. The shape has been changed to a rectangle (the height does not change) that extends only in the horizontal direction. In other words, the cross-sectional shape of the passage space 54a of the first bent passage portion 54B and the second bent passage portion 54C is a cross-sectional shape of the passage space 54a that is suddenly widened substantially in the horizontal direction with respect to the discharge passage portion 54A. ing.

  However, in the intake duct 51 where there is a portion where the cross-sectional shape of the passage space 54a changes, the air flow is disturbed such as separation or vortex in the portion where the cross-sectional shape changes. For this reason. In such an intake duct 51, even if air is sucked out from the exhaust port 53 at a uniform wind speed, the wind speed of the air sucked from the intake port 52 tends to be non-uniform. Actually, the wind speed of the portion of the intake port 52 closer to the exhaust port 53 (one end portion or the like) tends to be strong, and the wind speed of other portions tends to be weak (see FIG. 14).

  Thus, the tendency that the air velocity of the air sucked in at the intake port 52 finally becomes nonuniform is that the direction in which the air flows (advances) in the intake duct 51 changes regardless of the change in the cross-sectional shape of the passage space 54a. In this case, that is, when the passage space 54a has a bent shape in the middle, the same occurs. Further, the tendency of the air velocity of the air sucked at the air inlet 52 to be ultimately non-uniform occurs more prominently when the cross-sectional shape of the passage space 54a changes and the direction in which air flows (progress) also changes. .

  12a to 12c show representative examples 510A to 510C of intake ducts in which the intake port 52 and the exhaust port 53 are formed in different opening shapes, and the intake ports 52 in the respective ducts 510 are shown in the drawing. Each state of the wind speed of the air sucked in and the wind speed of the air exiting from the exhaust port 53 is indicated by the length of the arrow. That is, the longer the arrow, the faster the wind speed, and the shorter the arrow, the slower the wind speed. In FIG. 12, each intake duct 510 is shown as viewed from the upper surface side. Moreover, when the length of the arrow is the same in the figure, it indicates that the wind speed is the same. Furthermore, the dotted line in a figure has shown the passage space (side wall part which forms) of each duct. Incidentally, in the intake ducts 510B and 510C, the direction in which the air flows is changed in the middle (the passage space 54a is bent in the middle), and at least one of the sectional shape and the sectional area of the passage space is changed. It is also a configuration example. In addition, the intake duct 510D shown in FIG. 12d is a configuration example in which the intake port 52 and the exhaust port 53 are formed in the same opening shape (and the same opening area), and only the direction in which the air flows is in the middle. The duct has been changed.

  Therefore, the intake duct 51 of the intake device 5 according to Embodiment 1 has at least a passage space 54a for flowing air by connecting between the intake port 52 and the exhaust port 53, as shown in FIGS. The passage portion 54 formed in a bent form at one place (two places in this example) and two portions that suppress the flow of air at different portions (R) in the passage direction (R) of the passage space 54a of the passage portion 54. The suppression parts 61 and 62 are provided.

  One of the two suppressing portions (61, 62) is in a state in which the portion that is upstream in the direction of flowing air in the passage space 54a of the passage portion 54 is closed by the air-permeable member 70. It is provided as the “upstreammost suppression part”. In the first embodiment, the upstream portion is the intake port 52 that is the most upstream portion.

  The breathable member 70 is a member interspersed with a plurality of ventilation portions 71, for example. As shown in FIGS. 5 and 6, each of the plurality of ventilation portions 71 is a through-hole that extends so that each opening shape is substantially circular and penetrates linearly. In addition, the plurality of ventilation portions 71 are arranged at equal intervals along the longitudinal direction B of the opening shape of the intake port 52, for example, and are arranged in four rows at the same interval in the short direction C perpendicular to the longitudinal direction B. They are arranged to exist. As a result, the plurality of vent holes 71 are formed so as to be scattered throughout the entire opening shape of the intake port 52 which is the most upstream end of the suction passage portion 54A. For this reason, the air-permeable member 70 in Embodiment 1 is a perforated plate formed so that a plurality of ventilation portions (holes) 71 are dotted on a plate-like member. Furthermore, it is preferable that the plurality of ventilation portions 71 are formed so as to be scattered substantially uniformly (with a substantially constant density) with respect to the opening region of the intake port 52, but it is sucked from the intake port 52. As long as the air velocity of the generated air does not become a factor, it may be formed so as to exist in a slightly dense state.

  The breathable member 70 may be formed by integrally molding the same material as the intake duct 51 or may be formed of a material different from the duct 51. The opening shape, opening size, hole length, and hole density of the ventilation portion (hole) 71 are selected and set from the viewpoint of making the air velocity of the air sucked through the intake port 52 as uniform as possible. These values are set in consideration of the dimensions (capacity) of the duct 51 and the flow rate per unit time of air to be sucked into the duct 51 or sucked from the corona discharger 16 for charge adjustment.

  Further, the remaining restraining portions 62 of the two restraining portions (61, 62), as shown in FIG. 3 to FIG. 5 and the like, are provided at required portions of the first bending passage portion 54B. It is provided as a “most downstream restraint portion” that cuts off in a state where a part thereof is crossed and has a gap 63 extending in the crossing direction D to allow passage of air.

  The most downstream restraint portion 62 does not change the outer shape of the first bent passage portion 54B, and a plate-like blocking member 64 is provided in the passage space 54a of the bent passage portion 54B. It arrange | positions so that it may be in the state which crosses through the clearance gap (63) with respect to. Specifically, as shown in FIG. 5 and the like, the blocking member 64 blocks in a state where it crosses a portion of one side wall surface of the cross-sectional shape in the passage space 54a of the first bent passage portion 54B. One end portion 64a for forming the gap 63 is arranged in a state where a required interval H is provided with respect to one side wall surface portion of the cross-sectional shape of the passage space 54a. As a result, the most downstream restraint portion 62 has a structure in which an elongated substantially rectangular gap 63 extending in the transverse direction D exists on the side surface portion serving as one end of the blocking member 64 of the passage space 54a.

  About the height H, the path length M, and the width (length in the longitudinal direction B) W of the gap 63 that constitutes the most downstream restraint section 62, it flows into the first bent path section 54B from the second bent path section 54C. The air velocity is selected and set from the viewpoint of making the air velocity as uniform as possible and flowing it to the exhaust passage portion 54A. These values are set in consideration of the size (capacity) of the intake duct 51, the amount sucked by the intake duct 51, the flow rate of air sucked from the charging corona discharger 16, and the like.

  Hereinafter, the operation of the intake device 5 will be described.

  In the intake device 5, when a drive setting time such as an image forming operation is reached, first, the suction device 50 is rotationally driven to suck in a required amount of air. When the suction device 50 is started, as shown in FIGS. 7 and 8, the suction device 50 starts an operation of sucking and exhausting air (E), and the suction force of the air generated by the operation of the suction device 50 is increased. It extends to the intake duct 51 through the connection duct 55. Thereby, in the intake duct 51, the suction of air (E) is started at the intake port 52 thereof.

  At this time, the air (E2) existing in the passage space 54a of the exhaust passage portion 54A of the intake duct 51 is first sucked out from the exhaust port 53 by the suction force of the suction device 50. As a result, the air (E2) existing in the passage space 54a of the exhaust passage portion 54A flows almost along the direction R1 in which the air in the passage space 54a should flow, and finally gathers before the exhaust port 53. The air (E1) passes through the exhaust port 53 and flows out to the connection duct 55. When air is sucked out from the exhaust port 53 in this way, the suction force of the suction device 50 reaches the passage space 54a of the exhaust passage portion 54A.

  Subsequently, the air (E3) existing in the passage space 54a of the first bent passage portion 54B passes through the exhaust passage portion 54A by the suction force of the suction device 50 that has entered the passage space 54a of the exhaust passage portion 54A. It moves by being sucked into the space 54a. At this time, as shown in FIG. 8, the air (E3) passes through the gap 63 in the most downstream suppressing portion 62 in the passage space 54a of the first bending passage portion 54B, and enters the passage space 54a of the exhaust passage portion 54A. Flow into.

  At this time, the air (E3) existing in the passage space 54a of the first bent passage portion 54B tends to flow along the direction R2 in which the air flows in the passage space 54a, but a part thereof is the most downstream restraint. While the path is blocked by the blocking member 64 in the part 62, the remaining part of the path is suppressed by passing through the elongated narrow gap 63 in the most downstream suppressing part 62 (in a state where the pressure has increased). Then, the air flows into the passage space 54a of the exhaust passage portion 54A from the gap 63.

  Thereby, when there is no most downstream restraint part 62, the air (E3) which flows by being sucked into the exhaust passage part 54A from the first bent passage part 54B flows into the exhaust port 53 (actually in the first bent passage part 54B). Tends to flow as air (E3a) in an extremely displaced state (see FIG. 14) through the end region on the side close to the suction device 50). If present, as shown in FIG. 8, the air that passes through the region up to the end portion on the opposite side of the first bent passage portion 54B from the end portion on the side close to the exhaust port 53 ( E3b, E3c) are present in large numbers. When air (E3) passes through the gap 63 in the most downstream restraint portion 62, the suction force of the suction device 50 reaches the passage space 54a of the first bending passage portion 54B, and the suction force at this time is the first bending force. This also extends into the passage space 54a of the second bending passage portion 54C that is continuous with the passage portion 54B.

  Finally, the air (E5) existing outside the intake port 52 is caused by the suction force of the suction machine 50 that has entered the passage space 54a of the first bent passage portion 54B and the second bent passage portion 54C. 5 is sucked into the passage space 54a of the second passage portion 54C. At this time, the air (E5) passes through the air-permeable member 70 constituting the most upstream suppressing portion 61 provided in the intake port 52 and flows into the passage space 54a of the second bending passage portion 54C. Here, the air (E5) exists in the connection duct 56 between the intake duct 51 and the charging adjustment corona discharger 16 in the first embodiment, but it is substantially a corona discharger. The air is present in and around the sixteen shield cases 16a.

  At this time, the air (E5) existing outside the intake port 52 is sucked from the intake port 52 of the intake duct 51. At this time, the air (E5) forms the airflow member 70 constituting the most upstream suppressing portion 61. Passes through the plurality of ventilation portions (holes) 71 and flows into the passage space 54a of the second bending passage portion 54C. When air is sucked from the intake port 52 in this way, the suction force of the suction device 50 reaches the outside of the intake port 52.

  As a result, the air (E5) sucked from the intake port 52 passes through the plurality of ventilation portions 71 of the breathable member 70 that is relatively narrower than the opening area of the intake port 52, and the flow is suppressed (this (When the pressure rises)

  Further, the air (E5) sucked from the intake port 52 is scattered throughout the entire opening region of the intake port 52 and passes through the plurality of ventilation portions 71 formed under the same conditions. An environment in which the air is sucked from the intake port 52 is made uniform from an area substantially close to the shape. However, in actuality, in the longitudinal direction B of the intake port 52, the air (E3) that flows so as to pass through the clearance of the most downstream suppressing portion 62 by the suction force of the suction device 50 is illustrated in FIG. As described above, the velocity of the air (E3a) passing through the region of the end 63a closer to the exhaust port 53 in the gap 63 is the fastest, and passes through each region gradually separating from the end 63a of the gap 63. As the speed of the air (E3b, E3c) increases, the air speed is gradually decreased. That is, in the longitudinal direction B of the intake port 52, as illustrated in FIG. 7, the speed of the air (E5a) passing through the region of the end portion 52a on the side close to the exhaust port 53 of the intake port 52 is the fastest. The speed of the air (E5b, E5c, E5d) passing through the regions gradually separating from the end 52a of the intake port 52 gradually decreases as the distance increases. However, the speed (wind speed) difference in the longitudinal direction B of the air inlet 52 of the air (E5) at this time is a difference that does not cause a problem in practice (see FIG. 9).

  As described above, the air (E5) sucked from the intake port 52 passes through the plurality of ventilation portions 71 of the air-permeable member 70 in the most upstream suppressing portion 61, and the traveling direction thereof is the longitudinal direction B of the intake port 52. The air is sucked while being aligned in a substantially orthogonal direction, and the air suction speed in the longitudinal direction B of the air inlet 52 is prevented from being significantly different. In addition to the fact that the wind speed of the air (E5) sucked from the intake port 52 is suppressed from being significantly different in the longitudinal direction B of the opening shape (rectangular shape) of the intake port 52, It is also in a state in which a significant difference in the transverse direction C (FIG. 6, FIG. 8, etc.) that is substantially orthogonal is suppressed.

  Incidentally, the air (E5) sucked into the passage space 54a of the second bent passage portion 54C from the intake port 52 is connected to the first bent passage portion 54 in a bent state as shown in FIG. It stays in a state where it temporarily circulates in the passage space combined with the passage space 54a of the one-bending passage portion 54 (the upstream portion in the direction R2 in which air flows from the most downstream suppressing portion 62). As a result, the air (E5) sucked with a speed difference in the longitudinal direction B (and the short side direction C) of the air inlet 52 is mixed by being temporarily circulated and retained, and as a result, the speed difference is saturated. To some extent.

  The suction force of the air (E5) at the intake port 52 of the intake duct 51 reaches the inside of the shield case 16a of the charging adjustment corona discharger 16 and its opening 16b via the connection duct 56. As a result, the air present inside the shield case 16 a of the corona discharger 16 for charging adjustment and the air present around the opening 16 are sucked from the intake port 52 of the intake duct 51.

  At this time, the suction of air at the suction port 52 of the suction duct 51 is suppressed from significantly varying the suction speed of the air in the longitudinal direction B of the suction port 52, and the suction of air with less unevenness in the longitudinal direction B of the suction port 52 is suppressed. Therefore, air (E5) existing inside the shield case 16a of the corona discharger 16 for charging adjustment is also sucked into the intake duct 51 at substantially the same speed in the longitudinal direction B of the shield case 16a.

  Thereby, during operation of the corona discharger 16 for charge adjustment, ozone and discharge products generated in and around the shield case 16a are sucked almost uniformly with air (E5) in the longitudinal direction B of the shield case 16a. Will be. Therefore, according to the image forming unit 10 (Y, M, C, K) in which the intake device 5 is installed, for example, the suction of air by the intake device is extremely offset in the axial direction of the photosensitive drum 11. The ozone and discharge products generated in the corona discharger 16 for charging adjustment are attached in a state of being offset in the axial direction of the image holding surface of the photosensitive drum 11 corresponding to the side on which the suction of air by the intake device is relatively weak. It is possible to suppress the occurrence of image quality defects such as density unevenness due to the accumulation.

<Wind velocity distribution at the inlet>
FIG. 9 shows the result of a simulation performed on the wind speed distribution at the intake port 52 of the intake duct 51 in the intake device 5.

The simulation was performed on the assumption that the overall shape of the intake duct 51 was as shown in FIGS. 3 to 6 and the like, and that the following conditions were satisfied.
As the intake duct 51, an intake port 52 having a rectangular opening shape of 17.5 mm × 350 mm and an exhaust 53 having a substantially square opening shape of 22 mm × 23 mm was used. The most upstream restricting portion 61 has a porous member 70 provided with vent holes 71 having a hole diameter of 0.3 mm and a length of 3 mm under the condition that the density is 0.42 / mm ² (≈42 / cm ² ). As a polyhedral mesh. The most downstream restraint portion 62 is located at a position shifted by a dimension N = 6 mm from the bottom end portion 53d of the exhaust port 53 to the upstream side in the air flow direction R2 of the first bending passage portion 54B (FIG. 5). The gap 63 is configured to have an average height H of 1.5 mm, a path length M of 8 mm, and a width W of 345 mm.

  Further, the simulation is based on the premise that air of an air volume at which the average wind speed of the air sucked from the exhaust port 53 of the intake duct 51 is about 10 m / second is sucked from the suction machine 50, and the intake port 52 at that time The wind speed in the longitudinal direction B was measured. As shown in FIG. 8, the measurement is performed in the longitudinal direction B at three positions, ie, an upper position P1, an intermediate position P2, and a lower position P3 in the vertical direction of the intake port 52 (direction substantially parallel to the coordinate axis Y). It has been moved. In addition, this simulation was analyzed using thermal fluid analysis software (the number of iterations: 1000 times). In this simulation, the “k-ωSST model (emphasis on the velocity boundary of the wall surface neighborhood)” was applied as the physical model, and “Hybrid Wall Function (0.1 <Y + <100)” was applied as the wall surface model.

  In the graph of FIG. 9, the position where the position in the longitudinal direction of the horizontal axis (substantially the same as the axial direction of the photosensitive drum) is “0 mm” corresponds to the center position in the longitudinal direction B of the intake port 52. Further, the minus side (the left-hand side in the drawing) of the position in the longitudinal direction of the horizontal axis is the region of the end portion 52 a of the intake duct 51 on the side close to the intake port 52.

For reference, as shown in FIG. 13, the above simulation was performed in the same manner assuming a general intake duct (comparative example) 510C used in a conventional intake apparatus.
The intake duct 510C was assumed to have an overall shape as shown in FIGS. 12c and 13 and satisfy the following conditions. As the intake duct 510C, a suction opening 520 having a rectangular opening shape of 17.5 mm × 350 mm and a discharge 530 having a substantially square opening shape of 22 mm × 23 mm was used. Incidentally, the intake duct 510C is not provided with the restraining portions 61 and 62 as in the intake duct 51 according to the first embodiment.
The simulation results at this time are shown in FIG.

From the results shown in FIG. 14, in the conventional intake duct 510 </ b> C, with respect to the wind speed in the region of the end portion 520 a on the side close to the exhaust port 530 in the intake port 520, the region other than that in the intake port 520 It can be seen that the wind speed in the side region) is extremely small, and the distribution of the air suction speed in the longitudinal direction B of the intake port 520 is extremely offset.
On the other hand, from the result shown in FIG. 9, in the intake duct 51 provided with the plurality of suppressing portions 61 and 62 in the first embodiment, the distribution of the air suction speed in the longitudinal direction B of the intake port 52 is offset. It turns out that it is suppressed.

[Embodiment 2]
FIG. 10 shows an intake air device according to Embodiment 2, and shows an intake duct 51B in the intake device (5B).

  The intake device (5B) has the same configuration as that of the intake device 5 according to Embodiment 1 except that the intake duct 51B having a different configuration is used. As shown in FIG. 10, in this intake duct 51B, the first bent passage portion 54B and the second bent passage portion 54C in the first embodiment are changed to a first bent passage portion 54D and a second bent passage portion 54E having different configurations. In addition, the configuration is the same as that of the intake duct 51 in the first embodiment except that the third suppression unit 65 is added and changed. In the following description and drawings, common constituent elements are given the same reference numerals, and descriptions of the constituent elements are omitted unless necessary.

  That is, the first bent passage portion 54D of the intake duct 51B is changed in that the height of the portion on the upstream side in the direction R2 in which the air flows in the passage space 54a gradually becomes thinner as it becomes the downstream side. ing. In addition, the second bent passage portion 54E of the intake duct 51B has a width (in the longitudinal direction B) of the passage space 54a from a portion (side surface portion) which is a substantially intermediate point in the direction R2 in which the air flows in the first bent passage portion 54D. In the same state) and bent in a substantially horizontal direction so as to extend closer to the charging adjustment corona discharger 16, and at the end of the passage 54E, the end of the end This is changed in that an intake port 52 having an opening shape (rectangular shape) substantially the same as the cross-sectional shape of the passage space 54a is formed.

  The third suppression unit (middle suppression unit) 65 is provided at a portion between the most upstream suppression unit 61 and the most downstream suppression unit 62 in the direction in which air flows in the passage space 54a. Specifically, it is provided in the site | part which becomes the downstream of the direction which flows the air of the channel | path space 54a of the 2nd bending channel | path part 54E. Further, the middle-stage suppressing portion 65 is configured to have an elongated rectangular gap 66 extending in a direction parallel to the longitudinal direction B of the opening shape of the intake port 52.

  The middle-stage suppressing portion 65 in the second embodiment is changed to a shape that squeezes the outer shape of the second bending passage portion 54E, and the gap (narrow passage) is narrowed to the substantially central portion of the passage space 54a of the passage portion 54E. ) 66 is formed into a shape that exists. In addition, the height H, the path length M, and the width W of the gap 66 flow from the first bent path portion 54D to the second bent path portion 54E in substantially the same manner as the gap 63 in the most downstream suppressing portion 62. The air velocity is selected and set from the viewpoint of making the air velocity as uniform as possible, and the size (capacity) of the intake duct 51B, the entire passage space 54a of the intake duct 51B, or the air to be sucked out from the corona discharger 16 for charge adjustment It is set in consideration of the flow rate per unit time.

  Hereinafter, the operation of the intake device (5B) will be described.

  In this intake device, the suction force of the air generated by the operation of the suction machine 50 reaches the intake duct 51 through the connection duct 55, whereby the intake duct 51B starts to suck air (E) at the intake port 52 thereof.

  At this time, the air (E2) existing in the passage space 54a of the exhaust passage portion 54A of the intake duct 51B is exhausted from the exhaust port 53 by the suction force of the suction device 50, as in the case of the intake duct 51 according to Embodiment 1. Sucked out. Thereby, the air (E2) existing in the passage space 54a of the exhaust passage portion 54A finally passes through the exhaust port 53 as the air (E1) gathered before the exhaust port 53 and flows out to the connection duct 55. When the air (E2) is sucked out from the exhaust port 53 in this way, the suction force of the suction machine 50 reaches the passage space 54a of the exhaust passage portion 54A.

  Subsequently, the air (E3) existing in the passage space 54a of the first bending passage portion 54D passes through the exhaust passage portion 54A by the suction force of the suction machine 50 that has entered the passage space 54a of the exhaust passage portion 54A. It moves by being sucked into the space 54a. At this time, as shown in FIG. 11, the air (E3) passes through the gap 63 in the most downstream restraint portion 62 in the passage space 54a of the first bending passage portion 54D and enters the passage space 54a of the exhaust passage portion 54A. Flow into.

  At this time, the air (E3) existing in the passage space 54a of the first bent passage portion 54D tends to flow along the direction R2 in which the air flows in the passage space 54a, but a part thereof is the most downstream restraint. While the path is blocked by the blocking member 64 in the part 62, the remaining part of the path is suppressed by passing through the elongated narrow gap 63 in the most downstream suppressing part 62 (in a state where the pressure has increased). Then, the air flows into the passage space 54a of the exhaust passage portion 54A from the gap 63.

  Thereby, also in the intake duct 51B, as in the case of the intake duct 51 according to the first embodiment, the end of the first bent passage portion 54D on the side opposite to the end region on the side close to the exhaust port 53 is provided. There will be a lot of air (E3b, E3c) passing through the entire region (see FIG. 8). When air (E3) passes through the gap 63 in the most downstream restraint portion 62, the suction force of the suction device 50 reaches the passage space 54a of the first bending passage portion 54D, and the suction force at this time is the first bending force. It extends into the passage space 54a of the passage portion 54D.

  Subsequently, the air (E7) existing in the passage space 54a of the second bending passage portion 54E is caused by the suction force of the suction device 50 that has entered the passage space 54a of the first bending passage portion 54D. It moves by being sucked into the passage space 54a of the portion 54D. At this time, as shown in FIG. 11, the air (E7) passes through the gap 66 in the middle suppression portion 65 in the passage space 54a of the second bending passage portion 54E and passes through the passage space 54a of the first bending passage portion 54D. Flows in.

  At this time, the air (E7) existing in the passage space 54a of the second bending passage portion 54E tends to flow along the direction R2 in which air flows in the passage space 54a, but is elongated and narrow in the middle-stage suppression portion 65. It passes through the gap 66 and is in a suppressed state (a state in which the pressure is increased), and flows from the gap 66 into the passage space 54a of the first bent passage portion 54D. When the air (E7) passes through the gap 66 in the middle suppression portion 65, the suction force of the suction device 50 reaches the passage space 54a of the second bending passage portion 54E.

  As a result, in the intake duct 51B as well, as in the case of the intake duct 51 according to the first embodiment, the second bent passage portion 54E has an end portion on the opposite side to the end region on the side close to the exhaust port 53. There will be a lot of air (E7b, E7c) that passes through the entire region. Further, the air (E7) flowing into the passage space 54a of the first bent passage portion 54D is a passage space of the first bent passage portion 54D having a larger volume than the passage space 54a of the second bent passage portion 54E and the space of the gap 66. It stays in a state of being temporarily circulated in 54a. Thereby, the air (E7) sucked with a speed difference in the longitudinal direction B of the passage space 54a of the first bending passage portion 54D is mixed as a result of temporarily circulating and staying like the air (E6), The speed difference is saturated and eliminated to some extent.

  Finally, due to the suction force of the suction device 50 that has entered the passage space 54a of the second bent passage portion 54E, the air (E8) existing outside the intake port 52 passes through the intake port 52 of the intake duct 51B to the second. It is sucked into the passage space 54a of the passage portion 54E. At this time, the air (E8) passes through the air-permeable member 70 constituting the most upstream suppressing portion 61 provided in the intake port 52 and flows into the passage space 54a of the second bending passage portion 54C.

  At this time, the air (E8) existing outside the intake port 52 is sucked from the intake port 52 of the intake duct 51B. At this time, the air (E8) forms the airflow member 70 that constitutes the most upstream suppressing portion 61. Passes through the plurality of ventilation portions (holes) 71 and flows into the passage space 54a of the second bending passage portion 54E. When air is sucked in at the intake port 52 in this way, the suction force of the suction device 50 reaches the outside of the intake port 52.

  Thereby, the air (E8) sucked from the air inlet 52 of the intake / intake duct 51B passes through the plurality of ventilation portions 71 of the air-permeable member 70 that is relatively narrower than the opening area of the air inlet 52, thereby suppressing the flow. (In this case, the pressure is also increased) and sucked.

  Further, the air (E8) sucked from the intake port 52 of the intake duct 51B is scattered throughout the entire opening area of the intake port 52 and passes through the plurality of ventilation portions 71 formed under the same conditions. An environment in which the air is sucked from the air intake port 52 in a uniform state from an area substantially close to the opening shape of the air port 52 is obtained. However, in actuality, in the longitudinal direction B of the intake port 52, when flowing so as to pass through the clearance 63 of the most downstream suppression portion 62 and the clearance 66 of the middle suppression portion 65 due to the suction force of the suction device 50. Air (E3, E7) has the fastest speed of air (E3a, etc.) passing through the region of the end portions 63a, 66a on the side close to the exhaust port 53 of the gaps 63, 66. The air (E3b, E3c) passing through the regions gradually separating from the end portions 63a, 66a is affected by the fact that the velocity gradually decreases as the velocity increases. That is, in the longitudinal direction B of the intake port 52, the speed of the air (E8a) passing through the region of the end portion 52a on the side close to the exhaust port 53 of the intake port 52 is the fastest. The speed of the air (E8b, E8c, E8d) passing through each region gradually separating from the portion 52a gradually decreases as the distance increases (see FIG. 7). However, the speed (wind speed) difference in the longitudinal direction B of the air inlet 52 of the air (E8) at this time is a difference that does not cause a problem in practice.

  As described above, the air (E8) sucked from the intake port 52 of the intake duct 51B passes through the plurality of ventilation portions 71 of the air-permeable member 70 in the most upstream suppressing portion 61, so that the traveling direction of the air (E8) While being sucked in the direction substantially perpendicular to the longitudinal direction B, the suction speed of the air in the longitudinal direction B of the intake port 52 is suppressed from being significantly different. In addition to the fact that the wind speed of the air (E8) sucked from the intake port 52 is suppressed from being significantly different in the longitudinal direction B of the opening shape (rectangular shape) of the intake port 52, It is also in a state in which a significant difference in the lateral direction C (such as FIG. 10) that is substantially orthogonal is suppressed.

  Incidentally, the air (E8) sucked into the passage space 54a of the second bent passage portion 54E from the intake port 52 is in a state where the flow is suppressed by the middle suppression portion 65, and therefore the passage of the second bent passage portion 54E. It stays in the space 54a in a state of being temporarily circulated. As a result, the air (E8) sucked with a speed difference in the longitudinal direction B (and the short side direction C) of the air inlet 52 is mixed by being temporarily circulated and retained, so that the speed difference is saturated. To some extent.

  The suction force of the air (E8) at the intake port 52 of the intake duct 51B reaches the inside of the shield case 16a of the charging adjustment corona discharger 16 and its opening 16b via the connection duct 56. As a result, the air present inside the shield case 16 a of the corona discharger 16 for charging adjustment and the air present around the opening 16 are sucked from the intake port 52 of the intake duct 51.

  At this time, the suction of air at the suction port 52 of the suction duct 51B is suppressed from significantly different in the suction speed of the air in the longitudinal direction B of the suction port 52, and the suction of air with less unevenness in the longitudinal direction B of the suction port 52 is suppressed. Therefore, air (E5) existing inside the shield case 16a of the corona discharger 16 for charging adjustment is also sucked into the intake duct 51 at substantially the same speed in the longitudinal direction B of the shield case 16a.

  As described above, according to the intake duct 51B, during operation of the charging adjustment corona discharger 16, ozone and discharge products generated in and around the shield case 16a are air (in the longitudinal direction B of the shield case 16a). Aspirated almost uniformly with E8). Therefore, according to the image forming unit 10 (Y, M, C, K) in which the intake device 5 (B) is installed, for example, the suction of the air by the intake device is performed extremely in the axial direction of the photosensitive drum 11. As a result, the ozone and discharge products generated in the corona discharger 16 for charge adjustment are offset in the axial direction of the image holding surface of the photosensitive drum 11 corresponding to the side on which suction of air by the intake device is relatively weak. It is possible to suppress the occurrence of image quality defects such as density unevenness due to adhesion and deposition.

[Other embodiments]
As the restraining portion in the intake duct 51, the case where the two restraining portions 61 and 62 are provided in the first embodiment, and the case where the three restraining portions 61, 62, and 65 are provided in the second embodiment is shown. There may be provided a plurality of ones or more. In addition, the suppression unit includes the most downstream suppression unit, all of which change the cross-sectional shape in the passage space 54a of the main body 54 of the duct 51 and the direction in which air flows in the passage space 54a. It is preferable to provide it at a site after (for example, immediately after).

  The most downstream restraint portion 62 is configured by using a breathable member 70 formed in the first and second embodiments so that a plurality of vent portions (holes) 71 are scattered almost uniformly over the entire opening region of the outlet 53. Although the case has been exemplified, the most downstream suppression portion 62 is represented by, for example, a porous member such as a nonwoven fabric applied to a filter or the like (a plurality of ventilation portions 71 are irregularly shaped through gaps). It is also possible to use a breathable member 70.

  Further, the intake duct 51 is not limited to the overall shape illustrated in the first and second embodiments, and other shapes can be applied. For example, the intake duct as illustrated in FIG. 510 (510A to 510C) may be applied.

  In addition, the target structure to which the intake device 5 (5B) is applied is not limited to the charging adjustment corona discharger 16 illustrated in the first and second embodiments, and is long in one direction that requires air suction. Any structure (component, component device, etc.) having a (target) portion may be used. Other target structures include, for example, a peripheral portion that is at least one of an upstream side and a downstream side in the rotation direction of the photosensitive drum 11 in a portion facing the photosensitive drum 11 of the developing device 14, and a drum cleaning device for the photosensitive drum 11. 17 and a charging device 12, a peripheral portion that is at least one of the upstream side and the downstream side in the rotation direction of the intermediate transfer belt 21 among the portions of the belt cleaning unit 26 that face the intermediate transfer belt 21. . In addition, in the image carrier represented by the photosensitive drum 11 and the intermediate transfer belt 21, a target structure in which unnecessary objects such as ozone and toner adhere to the surface and may cause image quality deterioration requires air suction. It becomes a thing.

  The image forming apparatus 1 is not particularly limited in the configuration of the image forming method and the like as long as the image forming apparatus 1 is equipped with a target structure to which the intake device 5 (5B) needs to be applied. If necessary, an image forming apparatus that forms an image made of a material other than the developer may be used.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 5 ... Air intake device 11 ... Photosensitive drum (image holding body)
16 ... Corona discharger for charging adjustment (target structure)
21. Intermediate transfer belt (image carrier)
43 ... Opening (longitudinal portion of the target structure)
50 ... suction machines 51, 51B ... intake duct (intake pipe)
52 ... Intake port 53 ... Exhaust port 54 ... Passage portion 54a ... Passage space 54B, 54D ... First bending passage portion (bending passage portion)
54C, 54E ... 2nd bending passage part (bending passage part)
61 .. most upstream suppression unit (one of a plurality of suppression units)
63, 66 ... gap 62 ... the most downstream restraint part (one of a plurality of restraint parts; a restraint part having a gap)
65 ... middle-stage suppression unit (one of a plurality of suppression units, a suppression unit having a gap)
70 ... Breathable member B ... Longitudinal direction E ... Air (flow)
R: Direction in which air in the introduction passage should flow

Claims (9)

It has a long opening shape in one direction parallel to a long longitudinal portion in one direction of the target structure requiring air suction, and is arranged in a state facing the longitudinal portion of the target structure to suck in air The air inlet,
An exhaust port that has an opening shape different from that of the intake port, and sucks out air sucked from the intake port;
A passage portion formed with a passage space for flowing air by connecting between the intake port and the exhaust port;
An intake pipe, comprising: a plurality of suppressing portions that are provided at different portions in the direction of flowing air in the passage space of the passage portion and suppress the flow of air.   Of the plurality of suppression portions, the most upstream suppression portion provided in the upstream portion in the direction of flowing air in the passage space of the passage portion is in a state where the passage space in the upstream portion is blocked by the air-permeable member. The intake pipe according to claim 1, which is formed as described above.   The intake pipe according to claim 2, wherein the most upstream suppressing portion is formed so as to block the intake port with the air permeable member.   Among the plurality of suppression units, at least one suppression unit of one or a plurality of suppression units provided at a site downstream of the most upstream suppression unit in the direction of flowing air in the passage space of the passage unit, The intake pipe according to claim 2 or 3, wherein the intake pipe is configured in a form having a gap extending in a direction parallel to a longitudinal direction of the opening shape of the intake port in the passage space. The passage portion has a bent passage portion after a direction in which air flows is bent,
The intake pipe according to claim 4, wherein the suppressing portion having the gap is provided in a required portion of the passage space of the bent passage portion. A suction machine for sucking air; and an intake pipe having an exhaust port connected to the suction machine,
6. An intake device according to claim 1, wherein the intake pipe is the intake pipe according to any one of claims 1 to 5.   The air intake device according to claim 6, wherein the target structure is at least one of a corona discharger, a developing device, and an image carrier. A target structure that requires air suction, and an intake device that sucks air present in the target structure,
An image forming apparatus, wherein the air intake device is the air intake device according to claim 6.   The image forming apparatus according to claim 8, wherein the target structure is at least one of a corona discharger, a developing device, and an image carrier.

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