Developing device and image forming apparatus

Abstract

A developing device and an image forming apparatus, the developing device including: a developing roller that rotates while holding a developer; an image holding body that is disposed so as to face the developing roller and that rotates; and a suction duct in which suction ports are formed corresponding to at least both end portions of the developing roller, and which sucks the developer from the image holding body side through the suction ports, and which has a developer separation structure disposed adjacent to the suction ports, and which separates the developer from the image holding body side through the suction ports. Developer is separated from the airflow using a change in orientation of the airflow within the suction duct.

Description

Technical Field

[0001] This invention relates to a developing apparatus and an image forming apparatus. Background Technology

[0002] An electrophotographic image forming apparatus includes a developing unit, which comprises an image holding body and a developing unit for supplying developing agent to the image holding body. The developing unit includes a developing roller that holds the developing agent on a surface. The developing agent held on the developing roller is transferred to the image holding body, thereby developing the electrostatic latent image on the image holding body. A portion of the developing agent not used for development floats near the developing roller and the image holding body. This floating developing agent is drawn in with an airflow and recovered. A filter is provided to prevent the developing agent from being discharged outside the image forming apparatus. The technique for recovering the floating developing agent is described in Patent Documents 1 and 2 below.

[0003] In Patent Document 1 below, the developer (toner) conveyed through the transfer pipe 29 and the suction pipe 31 is adsorbed by a magnet 35 and recovered. The developer is adsorbed onto the magnet 35 upstream of the filter 33. In Patent Document 2 below, the developer (toner) is accumulated in the pipe 4 arranged along the photosensitive drum 1. The accumulated developer is conveyed by a screw 6 and recovered into a toner recovery tank 9 located upstream of the filter 10. Note that the symbols mentioned above are those used in Patent Documents 1 and 2 below and are not related to the symbols used in the description of the embodiments of this application.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2005-242195

[0005] Patent Document 2: Japanese Patent Application Publication No. 11-161119

[0006] In recent years, there has been a demand for higher speeds in image forming apparatuses, which has led to an increase in the amount of developer recovered along with the airflow. This increase in recovered developer has resulted in earlier clogging of filters used to prevent developer from being discharged outside the image forming apparatus, or in the flow paths leading to those filters. Summary of the Invention

[0007] The purpose of this invention is to suppress filter clogging or developer buildup in the flow path leading to the filter caused by developer.

[0008] The invention involved in Scheme 1 is a developing apparatus, which includes: a developing roller that holds developer and rotates; an image holder that is configured to face the developing roller and rotates; and a suction pipe that has suction ports formed corresponding to at least two ends of the developing roller, through which developer is drawn from the image holder side, and has a developer separation structure that is configured adjacent to the suction ports, and separates the developer from the airflow by means of a change in the direction of the airflow in the suction pipe.

[0009] In the developing apparatus described in Scheme 1, the developer separation structure of Scheme 2 includes: a pendant wall that hangs down from the upper surface of the suction pipe and is configured to intersect the developer suction direction; and an upright wall that stands up from the lower surface of the suction pipe and is configured to intersect the developer suction direction. The pendant wall and the upright wall are arranged along the developer suction direction and are configured to partially overlap when viewed from the developer suction direction.

[0010] In the developing apparatus described in Scheme 2, the invention involved in Scheme 3 has a developing agent receiving member below the drooping wall for receiving the separated developing agent.

[0011] In the developing apparatus described in Scheme 3, the developer receiving component of Scheme 4 is detachable from the main body of the suction pipe.

[0012] The invention involved in Scheme 5, in the developing apparatus described in Scheme 3, includes a conveying mechanism that conveys the developer accumulated on the developer receiving member and discharges it from the suction pipe.

[0013] In the developing apparatus described in Scheme 2, the invention involved in Scheme 6 has the drooping wall positioned on the upstream side in the direction of developer suction, among the arranged drooping wall and the upright wall.

[0014] In the developing apparatus described in Scheme 1, the developer separation structure of Scheme 7 includes a curved flow path that causes the airflow in the suction pipe to bend up and down.

[0015] The invention involved in Scheme 8, in the developing apparatus described in Scheme 7, has a developing agent receiving member on the extension line of the downward guiding airflow portion of the curved flow path for receiving separated developing agent.

[0016] In the developing apparatus described in Scheme 8, the developer receiving component of Scheme 9 is detachable from the main body of the suction pipe.

[0017] The invention involved in Scheme 10, in the developing apparatus described in Scheme 8, includes a conveying mechanism that conveys developer accumulated on the developer receiving member and discharges it from the suction pipe.

[0018] In the developing apparatus described in Scheme 7, the curved flow path of Scheme 11 is a flow path in which the airflow on the upstream side in the direction of developer suction flows downward.

[0019] The invention involved in Scheme 12 is an image forming apparatus comprising: a developing apparatus as described in any one of Schemes 1 to 11; a charger for charging the surface of the image holder; an exposure apparatus for exposing the charged image holder to light, thereby forming an electrostatic latent image on the image holder; a transfer unit for directly or indirectly transferring a developing image obtained by developing the electrostatic latent image using a developing agent supplied from the developing roller onto paper; a fixing unit for fixing the developing image transferred onto the paper onto the paper; and a conveying device for conveying the paper by passing it through the transfer unit and the fixing unit.

[0020] Invention Effects

[0021] According to the first aspect of the present invention, compared to the case where there is no developer separation structure that separates the developer from the airflow by utilizing the change in the direction of the airflow in the suction pipe, filter clogging can be suppressed.

[0022] According to the second aspect of the invention, the developer separation structure is formed inside the suction pipe.

[0023] According to the third aspect of the invention, more developer accumulates in the developer receiver compared to the case where the developer receiver is located below the detached lower wall.

[0024] According to the fourth aspect of the invention, the developer that has been separated and collected can be discharged from the developing apparatus.

[0025] According to the fifth aspect of the invention, the developer that has been separated and collected can be discharged from the developing apparatus.

[0026] According to the sixth aspect of the present invention, compared to the case where the pendant wall is not positioned at the upstream side in the direction of developer suction, the suctioned developer can be separated from the airflow earlier.

[0027] According to the seventh aspect of the present invention, the developer can be separated from the airflow more efficiently than in cases where the airflow is bent in directions other than up and down.

[0028] According to the eighth aspect of the invention, compared to the case where the developer receiver is located at the position of the extension line of the portion of the downward guiding airflow that is separated from the curved flow path, more developer accumulates in the developer receiver.

[0029] According to the ninth aspect of the invention, the developer that has been separated and collected can be discharged from the developing apparatus.

[0030] According to the tenth aspect of the invention, the developer that has been separated and collected can be discharged from the developing apparatus.

[0031] According to the 11th aspect of the present invention, compared to a flow path where the airflow is not flowing downwards on the upstream side of the developer suction direction, the suctioned developer can be separated from the airflow earlier.

[0032] According to the 12th aspect of the present invention, compared to the case where the developing apparatus described in any of aspects 1 to 11 is not provided, the chance of the image forming apparatus stopping is reduced. Attached Figure Description

[0033] The embodiments of the present invention will be described in detail with reference to the following figures.

[0034] Figure 1 It is a diagram showing a schematic structure of an image forming apparatus;

[0035] Figure 2 This is a perspective view showing the appearance of the developer supply device of the developing apparatus of this embodiment;

[0036] Figure 3 This is a schematic diagram showing a cross-section of the developing apparatus according to this embodiment;

[0037] Figure 4 This is a schematic diagram showing the structure of the developer discharge device;

[0038] Figure 5 This is a diagram that roughly represents another structural example of a suction pipe;

[0039] Figure 6 This is a diagram that roughly represents another example of the structure of a suction pipe.

[0040] Symbol Explanation

[0041] 10-Image forming apparatus, 40-Developing apparatus, 42-Charger, 44-Exposure apparatus, 46, 94-Image holding body, 48-Developer supply device, 50, 52, 98-Developing roller, 54-Developer transport path, 56-Transport screw, 62, 100-Sealing roller, 64-Developer discharge device, 66, 88, 96-Suction pipe, 68-Suction fan, 70-Filter, 72, 90-Lower cover, 74-Lower portion of developer transport path, 76, 104-Protrusion, 78, 102-Suction port, 80-Developer receiver, 82, 108-Dangling wall, 84, 92-Upright wall, 86-Discharge screw, 106-First upright wall, 110-Second upright wall. Detailed Implementation

[0042] Figure 1 This diagram shows a schematic structure of the image forming apparatus 10. The image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, and a document transport unit 16. The image reading unit 12 is a component for optically reading the image of a document. The document is placed on a platen glass 18, and the image on the document is optically read using an image reading element 20, which is composed of a CCD or the like. By moving the image reading element 20 along the platen glass 18, the image of the entire document is read. Alternatively, the document can be transported by the document transport unit 16, and the image on the document is read using the image reading element 20 during the transport process. The document is transported sheet by sheet from the document feed tray 22 of the document transport unit 16 to the document output tray 24, and reading is performed during this process. In this case, the image reading element 20 reads the image of the entire document while remaining stationary.

[0043] The image forming unit 14 forms an image on paper P based on image information read by the image reading unit 12 or image information sent from an external device such as a personal computer. The image forming unit 14 is an electrophotographic apparatus that forms a color image on paper P using four colors of developer. The image forming unit 14 includes image forming units 26Y, 26M, 26C, and 26K that respectively form developer images of yellow (Y), magenta (M), cyan (C), and black (K). The image forming units 26Y, 26M, 26C, and 26K are identical except for the colors they form. Especially when it is not necessary to distinguish each color, Y, M, C, and K are omitted and the unit is referred to as image forming unit 26 for explanation. The image forming unit 14 includes: an intermediate transfer belt 28 for transferring developer images formed by image forming units 26 of each color; a transfer unit 30 for transferring the developer images on the intermediate transfer belt 28 onto paper P; and a fixing unit 32 for fixing the transferred developer images onto paper P. Furthermore, the image forming unit 14 includes: a paper container 34 for holding paper P; and a paper conveying device 36 for conveying paper P sequentially from the paper container 34, allowing it to pass through the transfer unit 30 and the fixing unit 32 in sequence.

[0044] The developer images of various colors formed by the image forming unit 26 are transferred onto the intermediate transfer belt 28 and overlapped. The developer images on the intermediate transfer belt 28 are conveyed to the transfer unit 30 along with the intermediate transfer belt 28, and there they are transferred onto the paper P conveyed by the paper conveyor 36. The paper P is further conveyed by the paper conveyor 36 to the fixing unit 32, where it is heated and pressurized to fix the developer images onto the paper P. The paper P with the formed image is conveyed by the paper conveyor 36 to the paper output tray 38.

[0045] As exemplified by the yellow image forming unit 26Y, the image forming unit 26 includes a developing apparatus 40, a charger 42, and an exposure apparatus 44. The developing apparatus 40 includes an image holder 46 and a developer supply device 48 that supplies developer to the image holder 46. The charger 42 charges the surface of the image holder 46. The exposure apparatus 44 irradiates the charged surface of the image holder 46 with light such as a laser beam to form an electrostatic latent image on the surface of the image holder 46. The exposure apparatus 44 controls the irradiated light according to image information acquired from the image reading unit 12 or an external device to form the electrostatic latent image. Developer is supplied from the developer supply device 48 to the image holder 46 with the electrostatic latent image formed, and the latent image is developed.

[0046] In the image forming apparatus 10, four image forming units 26 are provided corresponding to the four colors of the developer. The number of image forming units corresponds to the number of colors of the developer. When the developer is of one color, only one image forming unit is provided. In the image forming apparatus 10, the developer image formed by the image forming unit 26 is indirectly transferred to the paper P via the intermediate transfer belt 28. Alternatively, the developer image can be directly transferred from the image forming unit to the paper.

[0047] Figure 2 and Figure 3 This is a diagram showing the schematic structure of the developing apparatus 40 included in the image forming unit 26 of the image forming apparatus 10. Figure 2 This is a perspective view showing the structure of the main part of the developer supply device 48 of the developing apparatus 40. Figure 3 This is a cross-sectional view of the developer supply device 48 and the image holding body 46. Figure 2 , Figure 3 The vertical direction corresponds to the direction of gravity when the developing device 40 is placed on the image forming device 10.

[0048] The developing apparatus 40 is disposed within the image forming apparatus 10 with the image holder 46 facing the developer supply device 48. An electrostatic latent image is formed on the surface of the image holder 46, and is developed using developer supplied from the developer supply device 48. The developed image formed on the surface of the image holder 46 is transferred to a recording medium such as paper or to an intermediate transfer belt 28. The developed image transferred to the intermediate transfer belt 28 is then transferred to a recording medium. The developer can be a toner. The image holder 46 is, for example, a cylindrical photosensitive roller that rotates about the center line of the cylinder. Figure 3 In the diagram, the direction of rotation of the image holder 46 is indicated by arrow R. Through this rotation, developer images are sequentially formed on the image holder 46 at positions opposite to the developer supply device 48, and then the developer images are transferred to the position on the recording medium.

[0049] The developer supply device 48 includes developing rollers 50 and 52 that hold developer supplied to the image holder 46. The developer supply device 48 has two developing rollers 50 and 52, but there may be one or more developing rollers. The developing rollers 50 and 52 are configured to face the image holder 46. The developing rollers 50 and 52 are cylindrical, with their centerlines arranged along the direction extending from the centerline of the cylindrical image holder 46. Furthermore, the developing rollers 50 and 52 are arranged close together to form a gap with the image holder 46. Hereinafter, the area between the developing rollers 50 and 52 and the image holder 46 will be referred to as the "roller gap". The developing rollers 50 and 52 rotate about their centerlines. The direction of this rotation is the same as the direction of movement of the respective surfaces of the developing rollers 50 and 52 and the image holder 46 in the portion facing the image holder 46. The directions of rotation of the image holder 46 and the developing rollers 50 and 52 may also be opposite to each other. Hereinafter, the direction in which the surfaces of the developing rollers 50 and 52 move with the rotation of the image holder 46 will be described as the "direction of rotational movement," and the direction in which they intersect will be described as the "direction of intersection." The direction of intersection is also the direction in which the center lines of the developing rollers 50 and 52 extend.

[0050] The developing rollers 50 and 52 use magnetic force to attract and retain the developer on their surface. The developer is supplied to the roller gap as the developing rollers 50 and 52 rotate, developing the electrostatic latent image on the image holder 46.

[0051] The developer supply device 48 has a developer transport path 54 that supplies developer to and recovers from the developing rollers 50 and 52. The developer transport path 54 includes four straight paths 54A, 54B, 54C, and 54D. However, the number of developer transport paths 54 is not limited to four. The four straight paths 54 extend in intersecting directions. Each developer transport path 54 includes a transport screw 56 with helical blades. Each transport screw 56 is associated with its corresponding one of the four developer transport paths 54A, 54B, 54C, and 54D, and is designated as transport screw 56A, 56B, 56C, and 56D. As the transport screw 56 rotates, the helical blades agitate the developer while simultaneously transporting it along the direction of the developer transport path 54. Through agitation, the developer becomes charged. The developer transport path 54 also includes a transfer transport path (not shown) for transferring developer between the straight developer transport paths 54A to 54D.

[0052] Developer transport path 54A is a transport path for supplying developer to developing rollers 50 and 52, hereinafter referred to as developer supply transport path 54A. In developer supply transport path 54A, developer is transported along a cross direction and supplied to the upper developing roller 50. Developer is further transported from developing roller 50 to the lower developing roller 52. Developer transport path 54B is a transport path for transporting developer recovered from developing rollers 50 and 52, hereinafter referred to as developer recovery transport path 54B. Developer transport paths 54C and 54D are transport paths for sending developer transferred from developer recovery transport path 54B towards developer supply transport path 54A, hereinafter referred to as first intermediate developer transport path 54C and second intermediate developer transport path 54D, respectively.

[0053] The developer is conveyed in a circulating manner between the developer supply path 54A and the second intermediate developer supply path 54D. Developer delivered to the end of the developer supply path 54A is transferred to the second intermediate developer supply path 54D, and from there conveyed in the opposite direction to the opposite end within the second intermediate developer supply path 54D. Developer delivered to the end of the second intermediate developer supply path 54D is transferred back to the developer supply path 54A. During its conveyance along the developer supply path 54A, the developer is supplied throughout the entire length of the developing roller 50. Developer received by the recovery developer supply path 54B is conveyed to the end of the recovery developer supply path 54B, and from there transferred to the first intermediate developer supply path 54C. The developer is conveyed along the first intermediate developer supply path 54C toward another end, and from that other end transferred to the second intermediate developer supply path 54D.

[0054] The transfer of developer from the lower developer transport path 54 to the upper developer transport path 54 can be achieved using the magnetic force of a permanent magnet. For example, the transfer of developer from the supply developer transport path 54A to the second intermediate developer transport path 54D can be achieved using a cylinder with a permanent magnet integrally mounted coaxially with the end of the transport screw 56A. The cylinder rotates integrally with the transport screw 56A. The rotation of the cylinder draws the developer adsorbed on the permanent magnet to the higher second intermediate developer transport path 54D. The developer adsorbed on the permanent magnet is scraped off and placed into the second intermediate developer transport path 54D.

[0055] Excess developer held on developing rollers 50 and 52 is scraped off in a manner that brings its thickness to a predetermined value. The residue of developer remaining on the surfaces of developing rollers 50 and 52 after passing through the roller gap moves with the rotation of developing rollers 50 and 52. During this movement, the residue may sometimes come into contact with structures around developing rollers 50 and 52 (e.g., Figure 3 The developer (as indicated by symbols 58 and 60) collides with the image holder 46. The developer is scattered due to this impact. Furthermore, the developer is also scattered due to the impact when it falls into the developer collection path 54B. The scattered developer floats in the area surrounding the roller gap. To suppress the diffusion of the floating developer, a sealing roller 62 is provided downstream of the developing roller 52 in the direction R of rotational movement of the image holder 46. The sealing roller 62 extends along the image holder 46 and contacts its surface. A developer discharge device 64 is provided to collect the floating developer.

[0056] Figure 4 This diagram schematically illustrates the structure of the developer discharge device 64. The developer discharge device 64 includes a suction pipe 66 integrally disposed with the developer supply device 48 and a suction fan 68 connected to the suction pipe 66 via piping. The suction pipe 66 is positioned downstream of the roller gap in the direction R of rotational movement of the image holder 46 and the developing roller 52. Air is drawn from the area surrounding the roller gap via the suction pipe 66 and the suction fan 68. The developer contained in the drawn airflow is captured by a filter 70 positioned upstream of the suction fan 68.

[0057] like Figure 3 As shown, the suction conduit 66 can be formed by a part of a component defining the developer delivery path 54 and a lower cover 72 opposite to that part. The suctioned air flows through the lower portion of the component sandwiched between the defined developer recovery delivery path 54B and the first intermediate developer delivery path 54C (in Figure 3 The area between the middle part (shown by symbol 74) and the lower cover 72.

[0058] The suction pipe 66 has pipe-shaped protrusions 76 at both ends in the intersecting direction, protruding towards the roller gap. The protrusions 76 are provided corresponding to the ends of the developing rollers 50 and 52. Furthermore, in addition to the ends of the developing rollers 50 and 52, protrusions 76 can also be provided corresponding to the portion between them. The protrusions 76 have suction ports 78 that draw air from the roller gap and its surrounding area along with the developer. The direction from the surrounding area of ​​the roller gap towards the inside of the suction pipe 66 is described as the developer suction direction S. Furthermore, the protrusions 76 have a developer receiving member 80 at their lower part for receiving the drawn-in developer.

[0059] The protrusion 76 is provided with a developer separation structure adjacent to the suction port 78 to change the direction of the suction airflow, thereby separating the developer from the airflow. The developer separation structure may be disposed within the protrusion 76. The developer separation structure has two plate-shaped walls 82, 84, which are arranged to intersect the developer suction direction S. The walls 82, 84 are provided throughout the entire width of the tubular protrusion 76. The wall hanging down from the upper surface of the protrusion 76 is referred to as the hanging wall 82, and the wall standing up from the lower surface of the protrusion 76 is referred to as the standing wall 84. The hanging wall 82 is located at the front end of the protrusion 76, i.e., the end on the side of the roller gap periphery region, and the standing wall 84 is located further away from the roller gap periphery region than the hanging wall 82, i.e., on the inner side of the protrusion 76. The hanging wall 82 and the standing wall 84 are configured to partially overlap when viewed along the developer suction direction S. Thus, the direction of the airflow within the protrusion 76 sequentially changes to downward, upward, and downward again. In the region where the direction of this curved airflow changes, especially in the region where the direction changes from bottom to top, the developer separates. The separated developer is received by the developer receiver 80 at the bottom of the protrusion 76 and accumulates there. The developer receiver 80 can be positioned on the extension line of the portion of the protrusion 76 that guides the downward airflow. Alternatively, more downward-hanging walls and upward-hanging walls can be alternately arranged.

[0060] To discharge the developer accumulated in the developer receiver 80, a developer conveying mechanism, specifically a discharge screw 86, can be provided. The discharge screw 86 has helical blades that, by rotating, convey the developer along the axis of rotation, discharging it from the developer receiver 80. The discharge screw 86 discharges the developer periodically or irregularly. Furthermore, instead of relying on the discharge screw 86 for developer discharge, the developer receiver 80 can be detachable from the suction pipe 66 (specifically, from the lower cover 72 of the suction pipe). When maintaining the image forming apparatus 10, the operator can remove the developer receiver 80 and remove the accumulated developer.

[0061] The developer supply device 48 has a suction pipe 66 for discharging floating developer from the roller gap and its surrounding area. In the protrusion 76 of the suction pipe 66, developer is separated from the airflow by changing the direction of the airflow. Therefore, compared to the case where the developer is not separated, less developer reaches the filter 70, thereby suppressing clogging of the filter 70's mesh. During maintenance of the image forming apparatus 10, the frequency of cleaning or replacing the filter 70 is reduced. Furthermore, by separating the drawn-in developer from the airflow earlier, the developer accumulated in the suction pipe 66 downstream of the protrusion 76 and in the flow path leading to the filter 70 is also reduced. Therefore, the frequency of replacement of the developing apparatus due to flow path blockage within the suction pipe 66 is reduced.

[0062] Figure 5 This diagram illustrates another configuration of the suction pipe. In the suction pipe 66 described above, a raised wall 84 is formed by a plate-like component erected from the lower surface of the lower cover 72. In contrast, in... Figure 5 In the suction pipe 88 shown, a portion of the lower cover 90 separating the inner and outer sides of the suction pipe 88 defines an upright wall 92. The developer receiver 80 and the subsequent lower cover 90 form a stepped difference; if it is stepped, the portion equivalent to a vertical plate becomes the upright wall 92.

[0063] Figure 6 This diagram shows the structure of the suction pipe 96 corresponding to the image holding body 94 whose surface movement direction is upward. The suction pipe 96 has a protrusion 104, which has a suction port 102 between the developing roller 98 and the sealing roller 100. Inside the protrusion 104, a first upright wall 106, a drooping wall 108, and a second upright wall 110 are arranged along the developer suction direction, and a developer receiving member 112 is provided at the lower part. The airflow flows through the first upright wall 106, the drooping wall 108, and the second upright wall 110, bending vertically. In the part where the airflow bends, especially in the part where the direction changes from bottom to top, the developer is separated. The separated developer is received by the developer receiving member 112 and accumulates there. In order to remove the accumulated developer, the developer receiving member 112 can be made detachable, or a discharge mechanism such as a spiral member with spiral blades can be provided.

[0064] (Postscript) (1)

[0066] A developing apparatus comprising:

[0067] The developing roller keeps the developer rotating;

[0068] An image holder, configured to face the developing roller and rotate thereon; and

[0069] The suction pipe has suction ports corresponding to at least two ends of the developing roller, through which developer is drawn from the image holding body side, and has a developer separation structure disposed adjacent to the suction ports, which separates the developer from the airflow by utilizing the change in the direction of the airflow within the suction pipe. (2)

[0071] According to the developing apparatus described in (1), wherein,

[0072] The developer separation structure includes: a hanging wall extending from the upper surface of the suction pipe and configured to intersect the developer suction direction; and an upright wall extending from the lower surface of the suction pipe and configured to intersect the developer suction direction.

[0073] The drooping wall and the upright wall are arranged along the direction of developer suction and configured to partially overlap when viewed from the direction of developer suction. (3)

[0075] According to the developing apparatus described in (2), wherein,

[0076] The suction pipe has a developer receiver below the drooping wall to receive the separated developer. (4)

[0078] According to the developing apparatus described in (3), wherein,

[0079] The developer receiver is detachable from the main body of the suction pipe. (5)

[0081] The developing apparatus according to (3) includes a conveying mechanism.

[0082] The conveying mechanism delivers the developer that has accumulated on the developer receiver and discharges it from the suction pipe. (6)

[0084] According to the developing apparatus described in (2), wherein,

[0085] Of the arranged drooping walls and upright walls, the drooping walls are positioned on the upstream side in the direction of developer suction. (7)

[0087] According to the developing apparatus described in (1), wherein,

[0088] The developer separation structure includes a curved flow path that causes the airflow in the suction pipe to bend up and down. (8)

[0090] According to the developing apparatus described in (7), it has a developer receiver on the extension line of the downward guiding airflow portion of the curved flow path for receiving separated developer. (9)

[0092] According to the developing apparatus described in (8), wherein,

[0093] The developer receiver is detachable from the main body of the suction pipe. (10)

[0095] The developing apparatus according to (8) includes a conveying mechanism.

[0096] The conveying mechanism delivers the developer that has accumulated on the developer receiver and discharges it from the suction pipe. (11)

[0098] According to the developing apparatus described in (7), wherein,

[0099] The curved flow path is a flow path in which the airflow on the upstream side in the direction of developer suction flows downward. (12)

[0101] An image forming apparatus comprising:

[0102] The developing apparatus as described in any one of (1) to (11);

[0103] The charger charges the surface of the image holder.

[0104] An exposure apparatus that exposes a charged image holder with light to form an electrostatic latent image on the image holder;

[0105] The transfer unit directly or indirectly transfers the developer image obtained by developing the electrostatic latent image using developer supplied from the developing roller onto paper.

[0106] The fixing unit fixes the developer image transferred onto the paper onto the paper; and

[0107] A conveying device that conveys the paper by passing it through the transfer section and the fixing section.

[0108] According to the structure involved in (1), compared to the case where there is no developer separation structure that uses the change in the direction of the airflow in the suction pipe to separate the developer from the airflow, the clogging of the filter can be suppressed.

[0109] According to the structure involved in (2), the developer separation structure is formed inside the suction pipe.

[0110] According to the structure involved in (3), more developer accumulates in the developer receiver compared to the case where the developer receiver is located below the detached wall.

[0111] According to the structure involved in (4), the developer can be discharged from the developing apparatus and separated and collected.

[0112] According to the structure involved in (5), the developer can be discharged from the developing apparatus and separated and collected.

[0113] According to the structure involved in (6), compared to the case where the drooping wall is not positioned at the upstream side in the direction of developer suction, the developer that is suctioned can be separated from the airflow as early as possible.

[0114] According to the structure involved in (7), the developer can be separated from the airflow efficiently compared to the case where the airflow is bent in a direction other than up and down.

[0115] According to the structure involved in (8), more developer accumulates in the developer receiver compared to the case where there is a developer receiver at the position of the extension line of the downward guiding airflow that is separated from the curved flow path.

[0116] According to the structure involved in (9), the developer can be discharged from the developing apparatus and separated and collected.

[0117] According to the structure involved in (10), the developer can be discharged from the developing apparatus and separated and collected.

[0118] According to the structure involved in (11), compared to the case where the flow path is not the upstream side of the developer suction direction and the airflow flows downward, the developer that is suctioned can be separated from the airflow earlier.

[0119] According to the structure involved in (12), the chance of the image forming apparatus stopping is reduced compared to the case where the developing apparatus does not have any of the structures in (1) to (11).

[0120] The embodiments of the present invention described above are provided for illustrative purposes. Furthermore, these embodiments do not encompass the entirety of the invention, nor do they limit the invention to the disclosed methods. It will be apparent to those skilled in the art that various modifications and variations will be readily understood. These embodiments were chosen and described to most readily explain the principles and applications of the invention. Thus, those skilled in the art can understand the invention through various modifications that are assumed to be optimized for specific uses of various embodiments. The scope of the invention is defined by the foregoing claims and their equivalents.

Claims

1. A developing apparatus, comprising: The developing roller keeps the developer rotating; An image holder is configured to face the developing roller and rotate; and The suction pipe has suction ports corresponding to at least two ends of the developing roller, through which developer is drawn from the image holding body side, and has a developer separation structure disposed adjacent to the suction ports, which separates the developer from the airflow by utilizing the change in the direction of the airflow within the suction pipe.

2. The developing apparatus according to claim 1, wherein, The developer separation structure includes: a hanging wall extending from the upper surface of the suction pipe and configured to intersect the developer suction direction; and an upright wall extending from the lower surface of the suction pipe and configured to intersect the developer suction direction. The drooping wall and the upright wall are arranged along the direction of developer suction and configured to partially overlap when viewed from the direction of developer suction.

3. The developing apparatus according to claim 2, wherein, The suction pipe has a developer receiver below the drooping wall to receive the separated developer.

4. The developing apparatus according to claim 3, wherein, The developer receiver is detachable from the main body of the suction pipe.

5. The developing apparatus according to claim 3, further comprising a conveying mechanism. The conveying mechanism delivers the developer that has accumulated on the developer receiver and discharges it from the suction pipe.

6. The developing apparatus according to claim 2, wherein, Of the arranged drooping walls and upright walls, the drooping walls are positioned on the upstream side in the direction of developer suction.

7. The developing apparatus according to claim 1, wherein, The developer separation structure includes a curved flow path that causes the airflow in the suction pipe to bend up and down.

8. The developing apparatus according to claim 7, wherein a developer receiver is provided on the extension of the downward guiding airflow portion of the curved flow path for receiving separated developer.

9. The developing apparatus according to claim 8, wherein, The developer receiver is detachable from the main body of the suction pipe.

10. The developing apparatus according to claim 8, further comprising a conveying mechanism. The conveying mechanism delivers the developer that has accumulated on the developer receiver and discharges it from the suction pipe.

11. The developing apparatus according to claim 7, wherein, The curved flow path is a flow path in which the airflow on the upstream side in the direction of developer suction flows downward.

12. An image forming apparatus comprising: The developing apparatus according to any one of claims 1 to 11; The charger charges the surface of the image holder. An exposure apparatus that exposes a charged image holder with light to form an electrostatic latent image on the image holder; The transfer unit directly or indirectly transfers the developer image obtained by developing the electrostatic latent image using developer supplied from the developing roller onto paper. The fixing unit fixes the developer image transferred onto the paper onto the paper; and A conveying device that conveys the paper by passing it through the transfer section and the fixing section.

Images