Developing device and image forming apparatus

Abstract

The present application provides a developing device and an image forming apparatus. The developing device has: first and second conveying members configured in first and second conveying paths formed vertically in a gravitational direction to convey developer in a manner that the developer circulates between the first and second conveying paths; a developing device main body in which the first and second conveying paths are formed; and a developer discharge structure that discharges remaining developer discharged from the first conveying path to the outside through the second conveying path or between an end portion of the second conveying path and the developing device main body.

Description

Technical Field

[0001] This disclosure relates to developing apparatus and image forming apparatus. Background Technology

[0002] Japanese Patent Application Publication No. 2009-175768 discloses a developing apparatus comprising: a developing roller having a developing area for conveying toner to an electrostatic latent image developed into a toner image; a developing container having a developing roller housing portion for housing the developing roller, a first stirring chamber disposed obliquely below the developing roller housing portion, and a second stirring chamber adjacent to the developing roller housing portion and disposed above the first stirring chamber; a first stirring member disposed in the first stirring chamber, which stirs and conveys the toner in the first stirring chamber in a predetermined first conveying direction; and a second stirring member disposed in the second stirring chamber, which stirs and conveys the toner in the first stirring chamber in a predetermined first conveying direction. The toner in the second stirring chamber is stirred and conveyed simultaneously in a second conveying direction opposite to the first stirring chamber; and a connecting path is provided to connect the downstream end of the first stirring chamber in the first conveying direction to the upstream end of the second stirring chamber in the second conveying direction for conveying the toner from the downstream end of the first stirring chamber in the first conveying direction to the upstream end of the second stirring chamber in the second conveying direction. The connecting path is located on the side away from the developing roller relative to the rotation axis of the first stirring member, and the portion of the connecting path in contact with the second stirring chamber closest to the developing roller is formed at a position vertically below the axis of the developing roller. In this developing apparatus, a residual developer conveying member is also provided for stirring and conveying the developer retained between the developing roller and the first stirring member. Summary of the Invention

[0003] The purpose of this disclosure is to provide a developing apparatus and an image forming apparatus having a first transport path and a second transport path arranged adjacent to each other in the direction of gravity, wherein residual developer is discharged from the end of the first transport path arranged on the upper side, and the axial length of the first transport path and the second transport path can be adjusted.

[0004] According to a first aspect of this disclosure, a developing apparatus is provided, comprising: a first conveying member and a second conveying member disposed on a first conveying path and a second conveying path formed vertically in the direction of gravity, such that developer is conveyed in a manner that allows developer to circulate between the first conveying path and the second conveying path; a developing apparatus body having the first conveying path and the second conveying path formed internally; and a developer discharge structure, wherein residual developer discharged from the first conveying path is discharged to the outside through the second conveying path or through the end of the second conveying path between the developing apparatus body and the second conveying path.

[0005] According to a second aspect of this disclosure, the first conveying path and the second conveying path have the same axial length and are separated from each other by a partition wall. The developer discharge structure includes: an upper discharge port formed on a portion of the partition wall; and a lower discharge port formed below the end side of the second conveying path.

[0006] According to a third aspect of this disclosure, the first conveying path and the second conveying path have the same axial length and are separated from each other by a partition wall. The developer discharge structure includes: an upper discharge port formed on the end side of the partition wall; and a lower discharge port formed below the end side of the second conveying path. The upper discharge port and the lower discharge port are axially aligned.

[0007] According to the fourth aspect of this disclosure, a developer adhesion prevention component is disposed on the shaft of the second conveying component below the upper outlet.

[0008] According to the fifth aspect of this disclosure, a conveying blade for feeding developer toward the end side of the second conveying path is disposed on the shaft of the second conveying component below the upper outlet.

[0009] According to a sixth aspect of this disclosure, the axial length of the second conveying path is shorter than the axial length of the first conveying path, and the developer discharge structure includes: an upper discharge port formed below the end of the first conveying path; and a communicating space formed between the end of the second conveying path and the wall of the developing apparatus body, wherein the remaining developer discharged from the upper discharge port is discharged to the outside through the communicating space.

[0010] According to a seventh aspect of this disclosure, an image forming apparatus is provided, having the developing apparatus and a latent image carrier disposed opposite to the developing apparatus.

[0011] (Effect)

[0012] According to the first solution, a developing apparatus can be provided, which has a first conveying path and a second conveying path arranged adjacent to each other in the direction of gravity, and discharges residual developer from the end of the first conveying path arranged on the upper side, and the axial length of the first conveying path and the second conveying path can be adjusted.

[0013] According to the second scheme, the remaining developer can be discharged from the first conveying path to the outside of the developing apparatus body via the second conveying path.

[0014] According to the third scheme, the remaining developer can be discharged from the outside of the developing apparatus body by falling downwards in the direction of gravity from the first conveying path via the second conveying path.

[0015] According to the fourth scheme, it is possible to prevent residual developer discharged from the first conveying path from adhering to the shaft of the second conveying component.

[0016] According to the fifth scheme, it is possible to prevent residual developer discharged from the first transport path to the second transport path from remaining in the second transport path.

[0017] According to the sixth scheme, it is possible to prevent residual developer discharged from the first transport path from entering the second transport path.

[0018] According to the seventh embodiment, an image forming apparatus can be provided in which the axial lengths of the first and second transport paths can be adjusted in a developing apparatus having a first transport path and a second transport path arranged adjacent to each other in the direction of gravity, and residual developer being discharged from the end of the first transport path arranged on the upper side. Attached Figure Description

[0019] Figure 1 This is a side view showing the structure of an image forming apparatus according to an embodiment of the present disclosure.

[0020] Figure 2 This is a cross-sectional view of the developing apparatus according to the embodiments of the present disclosure, viewed from the direction extending from the developing apparatus.

[0021] Figure 3 This is a cross-sectional view of the developing apparatus according to the embodiments of this disclosure, viewed from the front side.

[0022] Figure 4 This is a cross-sectional view showing an example of the developer discharge structure of a developing apparatus according to an embodiment of the present disclosure.

[0023] Figure 5 This is a cross-sectional view showing the structure of the developing apparatus according to the second embodiment of this disclosure.

[0024] Figure 6 This is a cross-sectional view showing the structure of the developing apparatus according to the third embodiment of this disclosure.

[0025] Figure 7 This is a cross-sectional view showing the structure of the developing apparatus according to the fourth embodiment of this disclosure.

[0026] Figure 8 This is a cross-sectional view showing the structure of the developing apparatus according to the fifth embodiment of this disclosure. Detailed Implementation

[0027] Next, the first embodiment of this disclosure will be described with reference to the accompanying drawings. Figure 1The image forming apparatus 10 according to the first embodiment of the present disclosure is shown. The image forming apparatus 10 has an image forming apparatus body 12, and an image forming unit 14, a transfer device 16, a fixing device 18, and a paper feeding device 20 are disposed within the image forming apparatus body 12. In addition, a recording medium transport path 22 for transporting a recording medium such as paper is formed within the image forming apparatus body 12.

[0028] The image forming unit 14 forms an image on a recording medium using an electrophotographic method. The image forming unit 14 has, for example, four or more image forming units 24. The four image forming units 24 form, for example, toner images of different colors such as yellow, magenta, cyan, and black.

[0029] Each image forming unit 24 has a photosensitive drum 26. The photosensitive drum 26 is an example of an image holder, which holds the toner image transferred onto the recording medium on its outer peripheral surface while rotating. In addition, the image forming unit 24 is provided with a charging device 28 for charging the photosensitive drum 26, a developing device 30 for developing the charged latent image using a developing agent, and a cleaning device 32 for cleaning the transferred photosensitive drum 26. Furthermore, a light writing device 48 for forming a latent image on the charged photosensitive drum 26 is provided.

[0030] The transfer device 16 has an intermediate transfer belt 34. The toner image is transferred from the photosensitive drum 26 to the intermediate transfer belt 34 in one pass through the primary transfer unit 36, and the toner image transferred in the first pass is transferred to the recording medium in the second pass through the secondary transfer unit 38.

[0031] The intermediate transfer belt 34 is supported by multiple support members 40 so that it can rotate. In addition, a support member 42 is provided opposite to the secondary transfer member 38.

[0032] The fixing device 18 uses heat and pressure to fix the toner transferred to the recording medium onto the recording medium.

[0033] The paper feeding device 20 includes: a receiving section 44 that receives recording media in a stacked state; and a delivery member 46 that delivers the recording media received in the receiving section 44 toward the recording media delivery path 22.

[0034] The recording medium transport path 22 transports the recording medium from the paper feeder 20 to the secondary transfer unit 38 and the support unit 42, and then to the fixing unit 18, so as to further transport the recording medium to the outside of the image forming apparatus body 12.

[0035] In the image forming apparatus 10 configured as described above, the toner images formed on the outer peripheral surface of the photosensitive drum 26 are transferred onto the intermediate transfer belt 34 in one step, the toner images transferred onto the intermediate transfer belt 34 in one step are transferred onto the recording medium in a second step, and the toner images transferred onto the recording medium in a second step are fixed onto the recording medium by the fixing device 18.

[0036] Next, refer to Figure 2 The developing apparatus 30 of this embodiment will be described. It is a two-component developing apparatus that develops a developer composed of a carrier and a toner by stirring the toner to charge it. In the following description, "up" refers to the direction of gravity, "down" refers to the direction of gravity, and "up" refers to the direction of gravity without distinguishing between up and down; or simply "up and down direction." Furthermore, the direction orthogonal to the up and down direction of gravity, and extending from which the developing roller 52, the first conveying member 82, the second conveying member 84, etc., described later, are referred to as the axial direction. Moreover, the side of the first conveying path 62 where the developer supply port 70 is formed, described later... Figure 3 The left side of the paper is conveniently referred to as the supply end side, and the side of the lower section of the second conveying path 64 that is formed, namely the right side of the paper, is referred to as the discharge end side.

[0037] A developing apparatus 30 is disposed opposite to a photosensitive drum 26, which serves as an image holder. The developing apparatus 30 has a developing apparatus main body 50 shaped like a developing apparatus housing. Inside the developing apparatus main body 50, a developing roller 52, serving as a developing component, is disposed opposite to the photosensitive drum 26. The developing roller 52 includes: a magnetic roller 54 for forming a uniform magnetic field in the axial direction; and a developing sleeve 56 rotatably mounted on the outer periphery of the magnetic roller 54. The magnetic roller 54 is fixed to the developing apparatus main body 50 within the developing sleeve 56. The developing sleeve 56 is supported by a cylindrical component made of a non-magnetic material, allowing it to rotate freely relative to the developing apparatus main body 50. Above the developing roller 52, a layer thickness limiting member 58 is fixed to the developing apparatus main body 50, opposite to the developing sleeve 56, to limit the layer thickness of the developer. The layer thickness limiting member 58 is formed of a metal plate. The toner adhering to the area around the developing sleeve 56 is limited in layer thickness by the layer thickness limiting member 58 and then moves to the latent image formed on the photosensitive drum 26.

[0038] The developing apparatus body 50 is divided internally by a partition wall 60 that vertically separates its interior in the direction of gravity, and is provided with a first conveying path 62 and a second conveying path 64 formed vertically in the direction of gravity. The upper surface of the partition wall 60, which has an arc-shaped cross-section, constitutes the lower surface of the first conveying path 62. Furthermore, the lower surface of the partition wall 60, which has an arc-shaped cross-section, constitutes the upper surface of the second conveying path 64. The first conveying path 62 and the second conveying path 64 have the same axial length and extend axially. The developing roller 52 is positioned opposite to a developer supply port 66 formed axially on the first conveying path 62, and is supplied with developer from the first conveying path 62.

[0039] like Figure 3 As shown, the upper surface 68 of the developing apparatus body 50 is also the upper surface of the first transport path 62, but a developer supply port 70 is provided on the supply end side at a location corresponding to the upper part of the first transport path 62. A first connecting port 72 is formed on the partition wall 60, below the developer supply port 70 in the direction of gravity. A second connecting port 74 is also provided on the partition wall 60 at a position closer to the discharge end than the first connecting port 72. In addition, an upper discharge port 76 is provided on the partition wall 60 near the discharge end. Although the bottom surface 78 of the developing apparatus body 50 is also the bottom surface of the second transport path 64, a lower discharge port 80 is formed at a position closest to the discharge end.

[0040] In the first transport path 62 and the second transport path 64, a first transport component 82 and a second transport component 84 are respectively arranged in a rotatable manner. The first transport component 82 and the second transport component 84 are used to transport the developer in a manner that stirs the developer between the first transport path 62 and the second transport path 64 and circulates the developer.

[0041] like Figure 2 As shown, a third conveying path 86 is provided obliquely below the developing roller 52 in the direction of gravity for recycling the developer remaining in the developing roller 52 back to the second conveying path 64. A third conveying member 88 is rotatably arranged on this third conveying path 86.

[0042] like Figure 3As shown, the first conveying component 82, the second conveying component 84, and the third conveying component 88 have shaft centers 90, 92, and 94, respectively. The feed end side of the shaft center 90 of the first conveying component 82 is supported on the upper part of the feed end side of the developing apparatus body 50 by a first upper bearing B1, and the discharge end side is supported on the upper part of the discharge end side of the developing apparatus body 50 by a second upper bearing B2. Similarly, the feed end side of the shaft center 92 of the second conveying component 84 is supported on the lower part of the feed end side of the developing apparatus body 50 by a first lower bearing B3, and the discharge end side is supported on the lower part of the discharge end side of the developing apparatus body 50 by a second lower bearing B4. Here, the second upper bearing B2 supporting the discharge end side of the shaft center 90 of the first conveying component 82 and the second lower bearing B4 supporting the discharge end side of the shaft center 92 of the second conveying component 84 are positioned axially in the same direction.

[0043] In addition, in the first conveying component 82, the second conveying component 84, and the third conveying component 88, there are spiral-shaped conveying blades 96, 98, and 100 that are inclined in the same direction around the shaft centers 90, 92, and 94, respectively.

[0044] The conveying blades 96 of the first conveying component 82 are formed around the axis center 90 between the first connecting port 72 and the second connecting port 74. The conveying blades 98 of the second conveying component 84 are also formed around the axis center 92 between the first connecting port 72 and the second connecting port 74.

[0045] Furthermore, on the first conveying component 82, in the portion between the second connecting port 74 and the upper discharge port 76, are provided: a discharge conveying blade 102 whose blade inclination direction is opposite to that of the conveying blade 96; an adjusting blade 104 whose inclination direction is the same as that of the conveying blade 96; and an upper discharge blade 106 whose blade inclination direction is the same as that of the discharge conveying blade 102 and whose radial length is shorter. The discharge conveying blade 102 is formed such that a portion of the blade reaches the second connecting port 74. The upper discharge blade 106 is disposed within an upper discharge space 108, which is formed between an upwardly protruding portion of the partition wall 60 and a downwardly protruding portion of the upper surface of the first conveying path 62, and whose dimensions in both the vertical and width directions are smaller than those of the first conveying path 62.

[0046] Additionally, on the second conveying component 84, a developer return blade 110 with its blade tilting direction opposite to that of the conveying blade 98 and a lower discharge blade 112 with its blade tilting direction in the same direction as that of the conveying blade 98 are provided in the portion between the second connecting port 74 and the lower discharge port 80. The lower discharge blade 112 is disposed in a lower discharge space 114, which is formed between the downward protrusion of the partition wall 60 and the upward protrusion of the bottom surface of the second conveying path 64, and the diameter in both the vertical and width directions is smaller than that of the second conveying path 64.

[0047] With the above structure, the developer supplied from the developer supply port 70 falls downwards in the direction of gravity in the first conveying path 62 and is supplied to the second conveying path 64 through the first connecting port 72. It is then conveyed in the second conveying path 64 towards the discharge end via the second conveying member 84 to a point near the lower end of the second connecting port 74. The developer conveyed to the lower end of the second connecting port 74 is obstructed from its conveyance towards the discharge end by the developer return blade 110 and collides with the developer further conveyed from the supply end side within the second conveying path 64. As a result, the developer near the lower end of the second connecting port 74 is pushed upwards in the direction of gravity and fed into the first conveying path 62 through the second connecting port 74.

[0048] The developer fed into the first conveying path 62 is conveyed by the conveying blades 96 of the first conveying component 82 towards the first connecting port 72, i.e., the replenishment end, while simultaneously being supplied to the developing roller 52 from the developer supply port 66. The developer that is not supplied to the developing roller 52 and remains on the first conveying path 62 is conveyed by the first conveying component 82 to the first connecting port 74, where it falls downwards in the direction of gravity and is then supplied to the second conveying path 64 again, repeating the above cycle.

[0049] Additionally, a portion of the developer fed from the second conveying path 64 into the first conveying path 62 via the second connecting port 74 is conveyed towards the discharge end by the discharge conveying blade 102, and then pushed back towards the replenishment end by the adjusting blade 104 so as not to discharge more than a predetermined amount of developer. The remaining developer that is not returned towards the replenishment end by the adjusting blade 104 is conveyed towards the discharge end by the upper discharge blade 106 in the upper discharge space 108, falls downward in the direction of gravity at the upper discharge outlet 76, and is discharged into the lower discharge space 114 of the second conveying path 64. The remaining developer discharged into the lower discharge space 114 is further conveyed towards the discharge end by the lower discharge blade 112, and is finally discharged from the lower discharge outlet 80 to the outside of the developing apparatus body 50.

[0050] Thus, the upper discharge port 76, the lower discharge port 80, the discharge conveyor blade 102, the adjusting blade 104, the upper discharge blade 106, the upper discharge space 108, and the lower discharge blade 112 constitute a developer discharge structure that discharges the remaining developer discharged from the first conveyor path 62 to the outside through the second conveyor path 64.

[0051] On the other hand, the developer supplied to the developing roller 52 from the first conveying path 62, after development, the remaining developer is stripped from the developing roller 52 to the third conveying path 86, and further recycled from the third conveying path 86 to the second conveying path 64. It is then mixed and stirred together with new developer supplied by a developer replenishment device (not shown) by the second conveying component 84. Figure 3 As indicated by the arrow, at the discharge end of the developing apparatus body 50, the developer is pushed upward from the second communication port 74 to the first conveying path 62, and then supplied with such a flow of developer from the first conveying component 82 to the developing roller 52.

[0052] Here, the positional relationship between the developing roller 52, the second conveying component 84, and the third conveying component 88 is explained. For example... Figure 2 As shown, the axis center 92 of the second conveying member 84 is positioned above the axis center 94 of the third conveying member 88 in the direction of gravity. Furthermore, the axis centers 92 of both the second and third conveying members 84 are positioned below the axis center of the developing roller 52 in the direction of gravity. Additionally, the axis center 90 of the first conveying member 82 is positioned above the axis center of the developing roller 52 in the direction of gravity.

[0053] Therefore, since the diameter of the third conveying component 88 is smaller than the diameter of the second conveying component 84, the positional relationship between the bottom surface 78 of the second conveying path 64 and the bottom surface of the third conveying path 86 can be such that they are at the same height in the direction of gravity, or the bottom surface of the second conveying path 64 is slightly higher or slightly lower than the bottom surface of the third conveying path 86. Furthermore, in this embodiment, an example has been described where the axis center 92 of the second conveying component 84 is positioned above the axis center 94 of the third conveying component 88 in the direction of gravity. However, by appropriately selecting the diameters of the second and third conveying components 84, as long as the bottom surface of the second conveying path 64 and the bottom surface of the third conveying path 86 are at the same vertical height, the axis center 92 of the second conveying component 84 can also be at the same height as the axis center 94 of the third conveying component 88 or slightly lower in the direction of gravity.

[0054] Furthermore, a pre-set height partition 116 is formed between the second transport path 64 and the third transport path 86. This partition 116 is a plate-like wall protruding axially from near the bottom surface of the second transport path 64 and the bottom surface of the third transport path 86 towards the upward direction of gravity. The upper end 118 of the partition 116 is positioned upward in the direction of gravity beyond the imaginary straight line connecting the axis center 92 of the second transport path 84 and the axis center 94 of the third transport path 88. The height of the partition 116 in the direction of gravity can be any height, provided it allows the developer to be transported from the third transport path 86 to the second transport path 64 via the third transport path 88 and prevents the developer transported from the third transport path 86 to the second transport path 64 from returning to the third transport path 86.

[0055] Furthermore, if the separating member 116 between the second transport path 64 and the third transport path 86 has the function of preventing or stopping the developer transported from the third transport path 86 to the second transport path 64 from the third transport member 88 from the third transport path 86 to the second transport path 64 from returning to the third transport path 86, then any component can be used, as long as it is a plate with a free end in the direction of gravity, an opening formed in the separating member 116, or any other component that allows the developer to flow in one direction.

[0056] Next, refer to Figure 5 The structure of the developing apparatus 30A according to the second embodiment of this disclosure will be described. Furthermore, most of the structure of the developing apparatus 30A of the second embodiment is the same as that of the developing apparatus 30 of the first embodiment; therefore, the same structural elements are labeled with the same reference numerals and detailed descriptions are omitted, while different structural elements are described using different reference numerals.

[0057] In the developing apparatus 30A of Embodiment 2, similarly to the above embodiment, a first conveying member 82 is arranged in the first conveying path 62, and a second conveying member 84 is arranged in the second conveying path 64. The discharge end side of the shaft center 90 of the first conveying member 82 is axially supported on the upper part of the discharge end sidewall 120 of the developing apparatus body 50 by a second upper bearing B2.

[0058] On the other hand, the axial length of the second conveying path 64 is shorter than that of the first conveying path 62. A communicating space 124 is provided between the second conveying path 64 and the discharge end sidewall 120 of the developing apparatus body 50, separated by the developer stirring chamber sidewall 122, which is the end of the second conveying path 64. Therefore, the discharge end side of the axial center 92 of the second conveying member 84 disposed in the second conveying path 64 is axially supported by the developer stirring chamber sidewall 122 by the second lower bearing B4, and is shorter than the length of the axial center 90 of the first conveying member 82. The communicating space 124 is surrounded by the discharge end sidewall 120, the developer stirring chamber sidewall 122, the partition wall 60 which becomes a thick wall in the direction of gravity (the thick wall portion 126), and the bottom thick wall portion 128, which is the bottom surface of the developing apparatus body 50 and is formed to be thicker than the bottom surface of the portion of the second conveying path 64.

[0059] An upper discharge port 130 is formed at the discharge end of the thick-walled portion 126 of the partition wall, and a lower discharge port 132 is formed at the discharge end of the thick-walled portion 128 of the bottom surface. The upper discharge port 130 and the lower discharge port 132 are approximately in the same axial position.

[0060] The first conveying component 82 has an upper discharge blade 106A similar to that in the above embodiment, but differs in that it is formed over a longer axial distance up to the vicinity of the discharge end sidewall 120, that is, up to the upper discharge outlet 130.

[0061] A portion of the developer fed from the second conveying path 64 into the first conveying path 62 is conveyed toward the discharge end via the discharge conveying blade 102, and then pushed back toward the replenishment end by the adjusting blade 104 in such a way that no more than a predetermined amount of developer is discharged. The remaining developer that does not return toward the replenishment end by the adjusting blade 104 is conveyed toward the discharge end via the upper discharge blade 106A in the upper discharge space 108, causing the upper discharge outlet 130 to fall downward in the direction of gravity, and then fall freely in the connecting space 124, thereby being discharged to the outside of the developing apparatus body 50 from the lower discharge outlet 132.

[0062] The discharge conveyor blade 102, the adjusting blade 104, the upper discharge blade 106A, the upper discharge space 108, the upper discharge outlet 130, the connecting space 124, and the lower discharge outlet 132 constitute a developer discharge structure that discharges the remaining developer from the first conveying path 62 through the upper discharge outlet 130 to the outside of the developing apparatus body 50 through the connecting space 124.

[0063] Next, refer to Figure 6The structure of the developing apparatus 30B according to the third embodiment of this disclosure will be described. Furthermore, most of the structure of the developing apparatus 30B of the third embodiment is the same as that of the developing apparatuses 30 and 30A of the first and second embodiments. Therefore, the same structural elements are labeled with the same reference numerals and detailed descriptions are omitted; only different structural elements are described using different reference numerals.

[0064] In the developing apparatus 30B of Embodiment 3, similarly to the second embodiment described above, the axial length of the second conveying path 64 is shorter than the axial length of the first conveying path 62. A communicating space 124, separated by the developer stirring chamber sidewall 122 which is the end of the second conveying path 64, is provided between the second conveying path 64 and the discharge end sidewall 120 of the developing apparatus body 50. Furthermore, an upper discharge port 130 is formed at the discharge end of the partition wall thick-wall portion 126, where the partition wall 60 is thick in the direction of gravity, and a lower discharge port 132 is formed at the discharge end of the bottom surface thick-wall portion 128, where the bottom surface of the developing apparatus body 50 is thick. The axial positions of the upper discharge port 130 and the lower discharge port 132 are approximately the same.

[0065] Furthermore, the discharge end of the first conveying member 82, located on the first conveying path 62, is similar to that in the first and second embodiments, supported on the upper part of the discharge end sidewall 120 of the developing apparatus body 50 by a second upper bearing B2. On the other hand, the shaft center 92 of the second conveying member 84, located on the second conveying path 64, penetrates the developer stirring chamber sidewall 122, axially traverses the communicating space 124 to reach the discharge end sidewall 120 of the developing apparatus body 50, and is supported by a second lower bearing B4 fixed to the lower part of the discharge end sidewall 120. The blade structure formed on the first conveying member 82 is the same as that in the second embodiment described above, therefore detailed description is omitted.

[0066] A portion of the developer fed from the second conveying path 64 into the first conveying path 62 is conveyed towards the discharge end via the discharge conveying blade 102, and then pushed back towards the replenishment end by the adjusting blade 104 so as not to discharge more than a predetermined amount of developer. The remaining developer that does not return towards the replenishment end via the adjusting blade 104 is conveyed towards the discharge end via the upper discharge blade 106A in the upper discharge space 108, and falls downward in the direction of gravity from the upper discharge outlet 130. Within the communicating space 124, the remaining developer falls around the axial center 92 of the second conveying member 84 that axially traverses the communicating space 124, and is finally discharged from the lower discharge outlet 132 to the outside of the developing apparatus body 50.

[0067] The discharge conveyor blade 102, the adjusting blade 104, the upper discharge blade 106A, the upper discharge space 108, the upper discharge outlet 130, the connecting space 124, and the lower discharge outlet 132 constitute a developer discharge structure that discharges the remaining developer from the first conveying path 62 through the upper discharge outlet 130 to the outside of the developing apparatus body 50 through the connecting space 124.

[0068] Next, refer to Figure 7 The structure of the developing apparatus 30C according to the fourth embodiment of this disclosure will be described. Furthermore, the structure of the developing apparatus 30C of the fourth embodiment is substantially the same as that of the developing apparatus 30B of the third embodiment, except that a developer adhesion prevention member 134 is installed at the shaft center 92 of the second transport member 84. Therefore, the same structural elements are labeled with the same reference numerals, and detailed descriptions are omitted.

[0069] The developer adhesion prevention component 134 is disposed at the location where the shaft center 92 of the second conveying component 84 axially traverses the communicating space 124, particularly below the upper outlet 130. The developer adhesion prevention component 134 is shaped like a coil spring loosely wound in a spiral around the shaft center 92 of the second conveying component 84. Alternatively, a component from... Figure 7 (B) shows a blade-shaped component extending radially outward from the axis center 92 and contacting the wall of the developing apparatus body 50. As the axis center 92 of the second transport member 84 rotates, the developer adhesion prevention component 134 and the blade-shaped component rotate relative to each other around the axis center 92, but do not rotate relative to the developing apparatus body 50. Therefore, developer falling from above is prevented from adhering to or remaining around the axis center 92 of the second transport member 84.

[0070] Next, refer to Figure 8 The structure of the developing apparatus 30D according to the fifth embodiment of this disclosure will be described. In addition, the structure of the developing apparatus 30D of the fifth embodiment is basically the same as that of the developing apparatus 30 of the first embodiment, except that the upper discharge port 76 is provided on the discharge end side of the upper discharge space 108 and the upper discharge blade 106 is extended to the discharge end side of the upper discharge space 108. Therefore, the same structural elements are marked with the same reference numerals, and detailed descriptions are omitted.

[0071] Similar to the first embodiment, a portion of the developer fed from the second conveying path 64 into the first conveying path 62 is conveyed towards the discharge end via the discharge conveying blade 102, and then pushed back towards the replenishment end by the adjusting blade 104 so as not to discharge more than a predetermined amount of developer. The remaining developer that is not returned towards the replenishment end by the adjusting blade 104 is conveyed towards the discharge end via the upper discharge blade 106 in the upper discharge space 108, and falls downward in the direction of gravity through the upper discharge outlet 76. The remaining developer that falls into the lower discharge space 114 of the second conveying path 64, closest to the discharge end, falls around the axis center 92 of the second conveying member 84, and is finally discharged from the lower discharge outlet 80 to the outside of the developing apparatus body 50.

[0072] Within the lower discharge space 114, the lower discharge blade 112 is positioned near the discharge end sidewall 120. Therefore, any remaining developer discharged into the lower discharge space 114 is always pushed out toward the discharge end and discharged from the lower discharge outlet 80 to the outside of the developing apparatus body 50.

Claims

1. A developing apparatus comprising: A first conveying component and a second conveying component are configured on a first conveying path and a second conveying path that are at least partially overlapping in the direction of gravity, so as to convey developer in a manner that the developer circulates between the first conveying path and the second conveying path. The developing apparatus body has the first transport path and the second transport path formed inside it; as well as The developer discharge structure allows residual developer discharged from the first transport path to be discharged to the outside via the second transport path, or via the end of the second transport path between itself and the main body of the developing apparatus. The developer discharge structure includes: an upper discharge port, which is formed on the end side of the partition wall that separates the first transport path from the second transport path; And a lower discharge port, which is formed below the end side of the second conveying path, with the upper discharge port and the lower discharge port being axially aligned.

2. The developing apparatus according to claim 1, wherein, The first transmission path and the second transmission path have the same axial length.

3. The developing apparatus according to claim 1, wherein, On the shaft of the second conveying component, below the upper outlet, a developer adhesion prevention component is disposed.

4. The developing apparatus according to claim 1 or 2, wherein, On the shaft of the second conveying component, below the upper outlet, there is a conveying blade that delivers developer to the end side of the second conveying path.

5. A developing apparatus comprising: A first conveying component and a second conveying component are configured on a first conveying path and a second conveying path that are partially overlapped in the direction of gravity, so as to convey developer in a manner that the developer circulates between the first conveying path and the second conveying path. The developing apparatus body has the first transport path and the second transport path formed inside it; as well as The developer discharge structure allows residual developer discharged from the first transport path to be discharged to the outside via the second transport path, or via the end of the second transport path between itself and the main body of the developing apparatus. The developer discharge structure includes: The upper discharge outlet; it is formed below the end of the first conveying path; and A connecting space is formed between the end of the second transport path and the wall of the developing apparatus body. The remaining developer discharged from the upper outlet is discharged to the outside through the connecting space.

6. An image forming apparatus comprising: The developing apparatus according to any one of claims 1 to 5; and A latent image carrier positioned opposite the developing apparatus.

Images