Developing device, and image forming apparatus

Abstract

To stably supply a developer required for a development member as compared with the case where a second conveyance member is rotated at the same speed ratio as the rotation speed of the development member, in a development device having a first and a second conveyance paths arranged adjacent to each other vertically in the gravity direction.SOLUTION: The development device comprises: a first conveyance member 82 and a second conveyance member 84 which are arranged in a first conveyance path 62 and a second conveyance path 64 formed vertically adjacent to each other in the gravity direction, and which convey developers in such a manner that the developers circulate between the first conveyance path 62 and the second conveyance path 64; a development member 52 which is arranged facing the first conveyance path 62 and is supplied with the developer from the first conveyance path 62; and a drive device 120 which changes the relative speed ratio of the rotation speed of the development member 52 with respect to the rotation speed of the first conveyance member 84 and drives the development member 52.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a developing device and an image forming apparatus.

Background Art

[0002] In Patent Document 1 below, there are a developing roll that conveys toner to a developing area where an electrostatic latent image is developed into a toner image, a developing roll housing portion that houses the developing roll, a first stirring chamber disposed diagonally below the developing roll housing portion, and a second stirring chamber that is adjacent to the developing roll housing portion and disposed above the first stirring chamber. A developing container having the above, a first stirring member that is housed in the first stirring chamber and conveys the toner in the first stirring chamber while stirring it in a predetermined first conveyance direction, and a second stirring member that is housed in the second stirring chamber and conveys the toner in the second stirring chamber while stirring it in a second conveyance direction opposite to the first conveyance direction. In order to convey toner from the downstream end portion in the first conveyance direction of the first stirring chamber to the upstream end portion in the second conveyance direction of the second stirring chamber, a communication path that connects the downstream end portion in the first conveyance direction of the first stirring chamber and the upstream end portion in the second conveyance direction of the second stirring chamber, and is on the side away from the developing roll with respect to the rotation axis of the first stirring member, and among the surfaces of the communication path that contact the second stirring chamber, the portion located closest to the developing roll side is formed vertically below the axis of the developing roll. A developing device having the above communication path is disclosed. In this developing device, further, a retained developer conveying member for stirring and conveying the developer retained between the developing roll and the first stirring member is disposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to stably supply a developer required for a developing member in a developing device having a first conveying member and a second conveying member arranged adjacent to each other vertically in the direction of gravity, as compared with a device that rotates the developing member and the second conveying member at the same speed ratio.

Means for Solving the Problems

[0005] The developing device according to the first aspect of the present invention is arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and includes a first conveying member and a second conveying member that convey a developer so as to circulate the developer between the first conveying path and the second conveying path; a developing member arranged opposite to the first conveying path and supplied with the developer from the first conveying path; and a driving device that drives by changing a relative speed ratio between the rotational speed of the developing member and the rotational speed of the first conveying member.

[0006] The developing device according to the second aspect of the present invention is, in the invention of the developing device according to the first aspect, wherein the driving device drives the developing member and the second conveying member by separate power sources.

[0007] The developing device according to the third aspect of the present invention is, in the invention of the developing device according to the first aspect, wherein the driving device includes a clutch mechanism, and the clutch mechanism changes a relative speed ratio between the developing member and the second conveying member.

[0008] The developing device according to the fourth aspect of the present invention is, in the invention of the developing device according to the second or third aspect, wherein the driving device drives with a constant relative speed ratio between the first conveying member and the second conveying member.

[0009] The developing device according to the fifth aspect of the present invention is, in the developing device according to the fourth aspect, wherein the developing device has a third conveying path that houses a third conveying member that recovers and conveys the developer surplus in the developing member to the second conveying path, and the driving device drives with a constant relative speed ratio among the first conveying member, the second conveying member, and the third conveying member.

[0010] In the developing device according to the sixth aspect of the present invention, in the invention of the developing device according to the second or third aspect, the driving device drives the developing member and the first conveying member at a constant relative speed ratio.

[0011] In the developing device according to the seventh aspect of the present invention, in the invention of the developing device according to the sixth aspect, the developing device has a third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus on the developing member to the second conveying path, and the driving device drives the second conveying member and the third conveying member at a constant relative speed ratio.

[0012] In the developing device according to the eighth aspect of the present invention, in the invention of the developing device according to the sixth aspect, the developing device has a third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus on the developing member to the second conveying path, and the driving device drives the developing member, the first conveying member, and the third conveying member at a constant relative speed ratio.

[0013] In the developing device according to the ninth aspect of the present invention, in the invention of the developing device according to the second or third aspect, the developing device has a third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus on the developing member to the second conveying path, and the driving device drives the first conveying member and the third conveying member at a constant relative speed ratio.

[0014] In the developing device according to the tenth aspect of the present invention, in the invention of the developing device according to any one of the first to ninth aspects, the developing device has a third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus on the developing member to the second conveying path, and a partition member having a predetermined height is formed between the second conveying path and the third conveying path.

[0015] The image forming apparatus according to the eleventh aspect of the present invention includes any one of the developing devices according to the first to tenth aspects and a latent image carrier disposed opposite to the developing device.

Advantages of the Invention

[0016] According to the developing device of the first aspect of the present invention, in a developing device having a first conveying member and a second conveying member arranged adjacent to each other vertically in the gravitational direction, a developing device capable of stably supplying a developer required for the developing member can be provided as compared with a device that rotates the developing member and the second conveying member at the same speed ratio.

[0017] According to the developing device of the second aspect of the present invention, the rotating speeds of the developing member and the second conveying member can be independently rotated without depending on each other.

[0018] According to the developing device of the third aspect of the present invention, the rotating speeds of the developing member and the second conveying member can be independently rotated without depending on each other, and the number of power sources can be reduced as compared with the case where the developing member and the second conveying member are driven by individual power sources.

[0019] According to the developing device of the fourth aspect of the present invention, regardless of the rotating speed of the developing member, an amount of developer corresponding to the amount of developer supplied to the developing member can be circulated and conveyed from the second conveying path to the first conveying path.

[0020] According to the developing device of the fifth aspect of the present invention, regardless of the rotating speed of the developing member, an amount of developer corresponding to the rotating speed of the first conveying member can be recovered into the second conveying path.

[0021] According to the developing device of the sixth aspect of the present invention, an amount of developer required according to the rotating speed of the developing member can be supplied from the first conveying path to the developing member.

[0022] According to the developing device of the seventh aspect of the present invention, regardless of the rotating speed of the developing member, the surplus developer in the developing member can be circulated and conveyed to the first conveying path.

[0023] According to the developing device of the eighth aspect of the present invention, an amount of developer corresponding to the rotating speed of the developing member can be supplied to the developing member and recovered into the second conveying path.

[0024] According to the developing device of the ninth aspect of the present invention, regardless of the rotation speed of the developing member, it is possible to collect an amount of developer corresponding to the rotation speed of the first conveying member in the second conveying path.

[0025] According to the developing device of the tenth aspect of the present invention, it is possible to prevent the developer collected in the second conveying path from flowing back to the third conveying path.

[0026] Further, according to one aspect of the present invention, in a developing device having a first conveying member and a second conveying member arranged adjacent to each other in the vertical direction of the gravitational direction, compared with rotating the developing member and the second conveying member at the same speed ratio, it is possible to provide an image forming apparatus capable of stably supplying the developer required for the developing member.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0028] Next, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an image forming apparatus 10 according to the first embodiment of the present invention. The image forming apparatus 10 has an image forming apparatus main body 12, and an image forming unit 14, a transfer device 16, a fixing device 18, and a paper feeding device 20 are arranged in the image forming apparatus main body 12. Further, a recording medium conveyance path 22 for conveying a recording medium such as paper is formed in the image forming apparatus main body 12.

[0029] The image forming unit 14 employs an electrophotographic method and forms an image on a recording medium. The image forming unit 14 has, for example, a plurality of image forming units 24, such as four. The four image forming units 24 form toner images of mutually different colors, such as yellow, magenta, cyan, and black.

[0030] Each image forming unit 24 has a photosensitive drum 26. The photosensitive drum 26 is an example of an image holding member, and rotates while holding a toner image to be transferred to a recording medium on its outer peripheral surface. Further, 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 with a developer, and a cleaning device 32 for cleaning the photosensitive drum 26 after transfer. Furthermore, an optical writing device 48 for forming a latent image on the charged photosensitive drum 26 is provided.

[0031] The transfer device 16 has an intermediate transfer belt 34. On the intermediate transfer belt 34, toner images are primary transferred from the photosensitive drums 26 to a primary transfer member 36 respectively, and the primary transferred toner images are secondary transferred to a recording medium by a secondary transfer member 38.

[0032] The intermediate transfer belt 34 is supported so as to be rotatable by a plurality of support members 40. Further, a backup member 42 is provided facing the secondary transfer member 38.

[0033] The fixing device 18 fixes the toner image transferred to the recording medium to the recording medium using, for example, heat and pressure.

[0034] The paper feeding device 20 has a storage unit 44 for storing recording media in a stacked state, and a feeding member 46 for feeding the recording media stored in the storage unit 44 toward a recording medium conveyance path 22.

[0035] The recording medium conveyance path 22 conveys the recording medium from the paper feeding device 20 between the secondary transfer member 38 and the backup member 42, further conveys the recording medium to the fixing device 18, and further conveys the recording medium so as to be discharged outside the image forming apparatus main body 12.

[0036] In the image forming apparatus 10 configured as described above, the toner images respectively formed on the outer peripheral surface of the photosensitive drum 26 are primarily transferred to the intermediate transfer belt 34, the toner image primarily transferred to the intermediate transfer belt 34 is secondarily transferred to the recording medium, and the toner image secondarily transferred to the recording medium is fixed to the recording medium by the fixing device 18.

[0037] Next, with reference to FIG. 2, the developing device 30 of the present embodiment will be described. It is a two-component developing device that stirs a developer composed of a carrier and toner to charge the toner for development. In the following description, the upward direction of the gravitational direction is referred to as up, the downward direction of the gravitational direction is referred to as down, and when the up and down directions are not distinguished, it is referred to as the up and down directions of the gravitational direction, or simply the up and down directions. Further, the direction orthogonal to the up and down directions of the gravitational direction and in which the developing roll 52, the first conveying member 82, the second conveying member 84, etc., to be described later extend is referred to as the axial direction. Furthermore, the side where the developer supply port 70 of the first conveying path 62 to be described later is formed, that is, the left side of the paper surface in FIG. 3 is conveniently referred to as the supply end side, and the side where the lower discharge port 80 of the second conveying path 64 to be described later is formed, that is, the right side of the paper surface is referred to as the discharge end side for explanation.

[0038] The developing device 30 is disposed to face the photosensitive drum 26 as an image holding member. The developing device 30 has a developing device main body 50 in the form of a developing device housing. Inside the developing device main body 50, a developing roll 52 as a developing member is disposed to face the photosensitive drum 26. The developing roll 52 includes a magnet roll 54 for forming a uniform magnetic field in the axial direction, and a developing sleeve 56 rotatably mounted on the outer periphery of the magnet roll 54. The magnet roll 54 is fixed to the developing device main body 50 inside the developing sleeve 56. The developing sleeve 56 is a cylindrical member made of a non-magnetic material and is rotatably supported with respect to the developing device main body 50. A layer thickness regulating member 58 for regulating the layer thickness of the developer is fixed to the developing device main body 50 above the developing roll 52 so as to face the developing sleeve 56. The layer thickness regulating member 58 is formed of sheet metal. The toner adhering to the periphery of the developing sleeve 56 is regulated in layer thickness by the layer thickness regulating member 58 and then moved to the latent image formed on the photosensitive drum 26.

[0039] The developing device main body 50 is separated by a partition wall 60 that divides its interior vertically in the direction of gravity. A first conveyance path 62 and a second conveyance path 64 are respectively provided, which are formed vertically in the direction of gravity. The upper surface of the partition wall 60 with an arc-shaped cross-section constitutes the lower surface of the first conveyance path 62. Also, the lower surface of the partition wall 60 with an arc-shaped cross-section constitutes the upper surface of the second conveyance path 64. The axial lengths of the first conveyance path 62 and the second conveyance path 64 are the same, and they each extend in the axial direction. The developing roll 52 is disposed opposite to a developer supply port 66 formed along the axial direction in the first conveyance path 62, and the developer is supplied from the first conveyance path 62.

[0040] As shown in FIG. 3, the upper surface 68 of the developing device main body 50 is also the upper surface of the first conveyance path 62, but a developer supply port 70 is provided at the replenishment end side of the portion corresponding to the upper part of the first conveyance path 62. A first communication port 72 is formed at the portion of the partition wall 60 on the lower side in the direction of gravity of the developer supply port 70. Further, a second communication port 74 is provided in the partition wall 60 on the discharge end side with respect to the first communication port 72. Also, an upper-stage discharge port 76 is provided in the partition wall 60 at a portion close to the discharge end side. The bottom surface 78 of the developing device main body 50 is also the bottom surface of the second conveyance path 64, but a lower-stage discharge port 80 is formed at the portion closest to the discharge end side.

[0041] In the first conveyance path 62 and the second conveyance path 64, a first conveyance member 82 and a second conveyance member 84 for stirring and circulating the developer between the first conveyance path 62 and the second conveyance path 64 and conveying it are rotatably arranged.

[0042] As shown in FIG. 2, a third conveyance path 86 for returning and collecting the developer that is surplus in the developing roll 52 to the second conveyance path 64 is provided obliquely downward in the direction of gravity of the developing roll 52. A third conveyance member 88 is rotatably arranged in this third conveyance path 86.

[0043] As shown in FIG. 3, the first conveying member 82, the second conveying member 84, and the third conveying member 88 each have axial centers 90, 92, and 94. The supply end side of the axial center 90 of the first conveying member 82 is pivotally supported by the first upper bearing B1 at the upper part of the supply end side of the developing device main body 50, and the discharge end side is pivotally supported by the second upper bearing B2 at the upper part of the discharge end side of the developing device main body 50. Similarly, the supply end side of the axial center 92 of the second conveying member 84 is pivotally supported by the first lower bearing B3 at the lower part of the supply end side of the developing device main body 50, and the discharge end side is pivotally supported by the second lower bearing B4 at the lower part of the supply end side of the developing device main body 50. Here, the axial positions of the second upper bearing B2 that supports the discharge end side of the axial center 90 of the first conveying member 82 and the second lower bearing B4 that supports the discharge end side of the axial center 92 of the second conveying member 84 are the same.

[0044] In addition, the first conveying member 82, the second conveying member 84, and the third conveying member 88 are each provided with conveying blades 96, 98, and 100 that are spiral and inclined in the same direction around the axial centers 90, 92, and 94.

[0045] The conveying blade 96 of the first conveying member 82 is formed around the axial center 90 between the first communication port 72 and the second communication port 74. The conveying blade 98 of the second conveying member 84 is also formed around the axial center 92 between the first communication port 72 and the second communication port 74.

[0046] Furthermore, the first conveying member 82 is provided, in the portion between the second communication port 74 and the upper discharge port 76, with a discharge conveying blade 102 whose blade inclination direction is opposite to that of the conveying blade 96, an adjusting blade 104 whose blade 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 of the blade is short. The discharge conveying blade 102 is formed such that a part of the blade covers the second communication port 74. The upper discharge blade 106 is disposed in an upper discharge space 108 formed between a protruding portion of the partition wall 60 protruding upward and a protruding portion of the upper surface of the first conveying path 62 protruding downward, and the diameters in the vertical direction and the width direction are smaller than those of the first conveying path 62.

[0047] Further, on the second conveying member 84, between the second communication port 74 and the lower discharge port 80, a developer return blade 110 with the direction of blade inclination opposite to that of the conveying blade 98 and a lower discharge blade 112 with the same direction of blade inclination as the conveying blade 98 are provided. The lower discharge blade 112 is disposed in a lower discharge space 114 formed between a protruding portion of the partition wall 60 protruding downward and a protruding portion of the bottom surface of the second conveying path 64 protruding upward, and having diameters in the vertical and width directions smaller than those of the second conveying path 64.

[0048] With the above configuration, the developer supplied from the developer supply port 70 falls downward in the first conveying path 62 in the direction of gravity, is supplied to the second conveying path 64 through the first communication port 72, and is conveyed by the second conveying member 84 in the second conveying path 64 toward the discharge end direction near the lower part of the second communication port 74. The developer conveyed near the lower part of the second communication port 74 is prevented from being conveyed toward the discharge end direction by the developer return blade 110, and collides with the developer being further conveyed from the supply end side in the second conveying path 64. As a result, the developer near the lower part of the second communication port 74 is pushed upward in the direction of gravity and sent into the first conveying path 62 through the second communication port 74.

[0049] The developer sent into the first conveying path 62 is conveyed by the conveying blade 96 of the first conveying member 82 toward the first communication port 72, that is, toward the supply end direction, and is supplied onto the developing roll 52 from the developer supply port 66. The developer remaining in the first conveying path 62 without being supplied to the developing roll 52 is conveyed by the first conveying member 82 toward the supply end direction to the first communication port 74, then falls downward in the direction of gravity at the first communication port 74, is supplied again to the second conveying path 64, and repeats the above circulation.

[0050] Also, a part of the developer fed into the first conveyance path 62 from the second conveyance path 64 through the second communication port 74 is conveyed by the discharge conveyance blade 102 toward the discharge end, and is pushed back toward the supply end side by the adjustment blade 104 so that a developer amount exceeding a predetermined amount is not discharged. The surplus developer not returned toward the supply end side by the adjustment blade 104 is conveyed by the upper-stage discharge blade 106 toward the discharge end in the upper discharge space 108, falls downward in the gravity direction through the upper-stage discharge port 76, and is discharged into the lower discharge space 114 of the second conveyance path 64. The surplus developer discharged into the lower discharge space 114 is further conveyed toward the discharge end by the lower-stage discharge blade 112 and is finally discharged to the outside of the developing device main body 50 from the lower-stage discharge port 80.

[0051] Thus, the upper-stage discharge port 76, the lower-stage discharge port 80, the discharge conveyance blade 102, the adjustment blade 104, the upper-stage discharge blade 106, the upper discharge space 108, and the lower-stage discharge blade 112 constitute a developer discharge structure that discharges the surplus developer discharged from the first conveyance path 62 to the outside through the second conveyance path 64.

[0052] On the other hand, among the developer supplied from the first conveyance path 62 onto the developing roll 52, the surplus developer after the development is finished is peeled from the developing roll 52 toward the third conveyance path 86, recovered and conveyed from the third conveyance path 86 to the second conveyance path 64, mixed and stirred with the new developer supplied from a developer supply device (not shown) by the second conveyance member 84, and pushed up from the second communication port 74 to the first conveyance path 62 at the discharge end of the developing device main body 50 as shown by the arrow in FIG. 3, and again supplied onto the developing roll 52 by the first conveyance member 82, thus forming a flow of the developer.

[0053] Here, the positional relationship among the developing roll 52, the second conveying member 84, and the third conveying member 88 will be described. As shown in FIG. 2, the axial center 92 of the second conveying member 84 is disposed above the third conveying member 88 in the gravitational direction. Note that both the axial center 92 of the second conveying member 84 and the axial center 94 of the third conveying member 88 are disposed below the axial center of the developing roll 52 in the gravitational direction. Further, the axial center 90 of the first conveying member 82 is disposed above the axial center of the developing roll 52 in the gravitational direction.

[0054] Therefore, due to the fact that the diameter of the third conveying member 88 is smaller than that of the second conveying member 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 is such that they are at approximately the same height in the gravitational direction, 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. In this embodiment, an example where the axial center 92 of the second conveying member 84 is disposed above the axial center 94 of the third conveying member 88 in the gravitational direction is described. However, by appropriately selecting the diameters of the second conveying member 84 and the third conveying member 88, if the vertical relationship is such that the bottom surfaces of the second conveying path 64 and the third conveying path 86 are at approximately the same level, the axial center 92 of the second conveying member 84 may be at the same height as the axial center of the third conveying member 88, or slightly below in the gravitational direction.

[0055] Furthermore, a partition member 116 having a predetermined height is formed between the second conveying path 64 and the third conveying path 86. This partition member 116 is a plate-like wall surface that protrudes upward in the gravitational direction from near the bottom surface of the second conveying path 64 to the bottom surface of the third conveying path 86 and extends along the axial direction. The upper end 118 of this partition member 116 is on the upper side in the gravitational direction with respect to the virtual straight line connecting the axial center 92 of the second conveying member 84 and the axial center 94 of the third conveying member 88. The height of this partition member 116 in the gravitational direction may be any height as long as it allows the developer to be conveyed from the third conveying path 86 to the second conveying path 64 by the third conveying member 88 and can prevent the developer conveyed from the third conveying path 86 to the second conveying path 64 from returning to the third conveying path 86 again.

[0056] Also, as long as the partition member 116 between the second conveyance path 64 and the third conveyance path 86 has a function as a return prevention member that allows the developer to be conveyed from the third conveyance path 86 to the second conveyance path 64 by the third conveyance member 88, and can prevent or block the developer conveyed from the third conveyance path 86 to the second conveyance path 64 from returning to the third conveyance path 86 again, any member such as a plate body with the upper end in the gravitational direction being the free end or an opening formed in the partition member 116 can be adopted as long as it allows the developer to flow in one direction.

[0057] Next, with reference to FIGS. 4(A) and 4(B), the driving methods of the developing roll 52, the first conveyance member 82, the second conveyance member 84, and the third conveyance member 88 in the developing device 30 having the above configuration will be described. In FIG. 3(A), the developing device 30 has a driving device 120 that drives by changing the relative speed ratio between the rotation speed of the developing roll 52 and the rotation speed of the second conveyance member 84. This driving device 120 drives at least the developing roll 52 and the second conveyance member 84 by separate power sources, and includes a first power source M1 and a second power source M2. That is, the developing roll 52 is driven by the first power source M1, while the second conveyance member 84 is driven by the second power source M2.

[0058] Therefore, these independent first power source M1 and second power source M2 can drive the developing roll 52 and the second conveyance member 84 in a state where the relative speed ratio between the rotation speed of the developing roll 52 and the rotation speed of the second conveyance member 84 can be changed without depending on each other.

[0059] Also, as shown in FIG. 4(B), the driving device 120 may have clutch mechanisms C1 and C2. In FIG. 4(B), the developing roll 52 and the second conveyance member 84 are driven by the same power source M3 via the clutch mechanisms C1 and C2. By using these clutch mechanisms C1 and C2, the relative speed ratio of the rotation speeds of the developing roll 52 and the second conveyance member 84 can be independently changed.

[0060] Figs. 5(A) and 5(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above-described configuration. Similar to Fig. 4(A), the driving device 120A shown in Fig. 5(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the first conveying member 82 and the second conveying member 84 are driven by the same power source M2. Thereby, the rotation speed ratio between the first conveying member 82 and the second conveying member 84 becomes constant. On the other hand, the rotation speed ratio between the developing roll 52 driven by the first power source M1 and the first conveying member 82 and the second conveying member 84 driven by the second power source M2 is driven in a state where they can be changed without depending on each other.

[0061] In Fig. 5(B), the driving device 120A drives the developing roll 52, the first conveying member 82, and the second conveying member 84 by the same power source M3 via clutch mechanisms C1 and C2. The clutch mechanism C1 is disposed between the power source M3 and the developing roll 52, and the clutch mechanism C2 is disposed between the power source M3 and the first conveying member 82 and the second conveying member 84. By using the clutch mechanisms C1 and C2, the rotation speed ratio of the developing roll 52 and the rotation speed ratio of the first conveying member 82 and the second conveying member 84 are independently changed.

[0062] Figs. 6(A) and 6(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above-described configuration. Similar to Fig. 4(A), the driving device 120B shown in Fig. 6(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the first conveying member 82, the second conveying member 84, and the third conveying member 88 are driven by the same power source M2. Thereby, the rotation speed ratio of the first conveying member 82, the second conveying member 84, and the third conveying member 88 becomes constant. On the other hand, the rotation speed ratio between the developing roll 52 driven by the first power source M1 and the first conveying member 82, the second conveying member 84, and the third conveying member 88 driven by the second power source M2 is driven in a state where it can be changed without depending on each other.

[0063] In Fig. 6(B), the driving device 120B drives the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 by the same power source M3 via the clutch mechanisms C1 and C2. The clutch mechanism C1 is disposed between the power source M3 and the developing roll 52, and the clutch mechanism C2 is disposed between the power source M3 and the first conveying member 82, the second conveying member 84, and the third conveying member 88. By using the clutch mechanisms C1 and C2, the rotation speed ratio of the developing roll 52 and the rotation speed ratio of the first conveying member 82, the second conveying member 84, and the third conveying member 88 are changed independently.

[0064] Figures 7(A) and 7(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above-described configuration. Similar to FIG. 4(A), the driving device 120C shown in FIG. 7(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the developing roll 52 and the first conveying member 82 are driven by the same power source M1. Thereby, the rotation speed ratio between the developing roll 52 and the first conveying member 82 becomes constant. On the other hand, the rotation speed ratio between the developing roll 52 and the first conveying member 82 driven by the first power source M1 and the rotation speed ratio of the second conveying member 84 driven by the second power source M2 are driven in a state where they can be changed independently of each other.

[0065] In FIG. 7(B), the driving device 120C drives the developing roll 52, the first conveying member 82, and the second conveying member 84 by the same power source M3 via clutch mechanisms C1 and C2. The clutch mechanism C1 is disposed between the power source M3 and the developing roll 52 and the first conveying member 82, and the clutch mechanism C2 is disposed between the power source M3 and the second conveying member 84. By using the clutch mechanisms C1 and C2, the rotation speed ratio of the developing roll 52 and the first conveying member 82 and the rotation speed ratio of the second conveying member 84 are changed independently.

[0066] Figures 8(A) and 8(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above-described configuration. Similar to FIG. 4(A), the driving device 120D shown in FIG. 8(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the developing roll 52 and the first conveying member 82 are driven by the same power source M1, and the second conveying member 84 and the third conveying member 88 are driven by the same power source M2. As a result, the rotation speed ratio between the developing roll 52 and the first conveying member 82 becomes constant, and the rotation speed ratio between the second conveying member 84 and the third conveying member 88 becomes constant. On the other hand, the rotation speed ratio between the developing roll 52 and the first conveying member 82 driven by the first power source M1 and the rotation speed ratio between the second conveying member 84 and the third conveying member 88 driven by the second power source M2 are driven in a state where they can be changed independently of each other.

[0067] In FIG. 8(B), the driving device 120D drives the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 by the same power source M3 via clutch mechanisms C1 and C2. The clutch mechanism C1 is disposed between the power source M3 and the developing roll 52 and the first conveying member 82, and the clutch mechanism C2 is disposed between the power source M3 and the second conveying member 84 and the third conveying member 88. By using the clutch mechanisms C1 and C2, the rotation speed ratio between the developing roll 52 and the first conveying member 82 and the rotation speed ratio between the second conveying member 84 and the third conveying member 88 are independently changed.

[0068] Figs. 9(A) and 9(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above-described configuration. Similar to Fig. 4(A), the driving device 120E shown in Fig. 9(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the developing roll 52, the first conveying member 82, and the third conveying member 88 are driven by the same power source M1, and only the second conveying member 84 is driven by another power source M2. Thereby, the rotation speed ratio of the developing roll 52, the first conveying member 82, and the third conveying member 88 becomes constant. On the other hand, the rotation speed ratio of the developing roll 52, the first conveying member 82, and the third conveying member 88 driven by the first power source M1 and the rotation speed ratio of the second conveying member 84 driven by the second power source M2 are driven in a state where they can be changed independently of each other without depending on each other.

[0069] In Fig. 9(B), the driving device 120E drives the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 by the same power source M3 via clutch mechanisms C1 and C2. The clutch mechanism C1 is disposed between the power source M3 and the developing roll 52, the first conveying member 82, and the third conveying member 88, and the clutch mechanism C2 is disposed between the power source M3 and the second conveying member 84. By using the clutch mechanisms C1 and C2, the rotation speed ratio of the developing roll 52, the first conveying member 82, and the third conveying member 88 and the rotation speed ratio of the second conveying member 84 are changed independently.

[0070] Figures 10(A) and 10(B) show another example of the driving methods of the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 in the developing device 30 having the above configuration. Similar to FIG. 4(A), the driving device 120F shown in FIG. 10(A) drives the developing roll 52 and the second conveying member 84 by separate power sources M1 and M2. In addition to this, the first conveying member 82 and the third conveying member 88 are further driven by another identical power source M3. Thereby, the rotation speed ratio of the first conveying member 82 and the third conveying member 88 becomes constant. On the other hand, the rotation speed ratio of the developing roll 52 driven by the first power source M1, the rotation speed ratio of the second conveying member 84 driven by the second power source M2, and the rotation speed ratios of the first conveying member 82 and the third conveying member 88 driven by the third power source M3 are driven in a state where they can be changed without depending on each other.

[0071] In FIG. 10(B), the driving device 120F drives the developing roll 52, the first conveying member 82, the second conveying member 84, and the third conveying member 88 by the same power source M4 via clutch mechanisms C1, C2, and C3. The clutch mechanism C1 is disposed between the power source M4 and the developing roll 52, the clutch mechanism C2 is disposed between the power source M4 and the second conveying member 84, and the clutch mechanism C3 is disposed between the power source M4 and the first conveying member 82 and the third conveying member 88. By using the clutch mechanisms C1, C2, and C3, the rotation speed of the developing roll 52, the rotation speed of the second conveying member 84, and the ratio of the rotation speeds of the first conveying member 82 and the third conveying member 88 are independently changed.

[0072] Note that the first power source M1, the second power source M2, and the third power source M3 each include a stepping motor (not shown) and a gear mechanism for adjusting the rotation speed, are disposed inside the image forming apparatus main body 12, and are controlled and driven by a control device (not shown) that controls the operations of the respective parts of the image forming apparatus 10. The control device includes a CPU, a memory, a storage device, and a communication interface (not shown). The CPU is a control microprocessor and controls the operations of the respective parts of the image forming apparatus based on a control program stored in the storage device.

[0073] In addition, in each of the above embodiments, the processor refers to a processor in a broad sense, including a general-purpose processor (e.g., CPU: Central Processing Unit, etc.) and a dedicated processor (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0074] Also, the operation of the processor in each of the above embodiments may be achieved not only by one processor but also by a plurality of physically separated processors cooperating with each other. Also, the order of each operation of the processor is not limited to the order described in each of the above embodiments and may be changed as necessary.

Explanation of Reference Numerals

[0075] 10 Image forming apparatus 12 Image forming apparatus main body 14 Image forming section 16 Transfer device 18 Fixing device 20 Paper feeding device 22 Recording medium conveyance path 24 Image forming unit 24 Each image forming unit 26 Photoconductor drum 28 Charging device 30 Developing device 32 Cleaning device 34 Intermediate transfer belt 36 Primary transfer member 38 Secondary transfer member 40 Support member 42 Backup member 44 Storage section 46 Delivery member 48 Optical writing device 50 Developing device main body 52 Developing roll 54 Magnet Roll 56 Developing Sleeve 58 Layer Thickness Regulating Member 60 Partition Wall 62 First Conveyor Path 64 Second Conveyor Path 66 Developer Supply Port 68 Upper Surface 70 Developer Refill Port 72 First Communication Port 74 Second Communication Port 76 Upper Stage Discharge Port 78 Bottom Surface 80 Lower Stage Discharge Port 82 First Conveyor Member 84 Second Conveyor Member 86 Third Conveyor Path 88 Third Conveyor Member 90, 92, 94 Axis Center 96, 98 Conveyor Vane 102 Discharge Conveyor Vane 104 Adjustment Vane 106 Upper Stage Discharge Vane 108 Upper Discharge Space 110 Developer Return Vane 112 Lower Stage Discharge Vane 114 Lower Discharge Space 116 Partition Member 118 Upper End 120, 120A - 120F Driving Device B1, B2 Upper Stage Bearing B3, B4 Lower Stage Bearing C, C1 - C3 Clutch Mechanism M1 - M4 Power Source

Claims

1. First and second conveying members arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and conveying a developer so as to circulate the developer between the first conveying path and the second conveying path through a first communication port and a second communication port formed in a partition wall between the first conveying path and the second conveying path; A developing member arranged opposite to the first conveying path and supplied with a developer from the first conveying path; A third conveying path for accommodating a third conveying member that collects and conveys the developer remaining in the developing member to the second conveying path; A driving device that drives the first conveying member and the second conveying member by separate power sources so that the relative speed ratio between the rotation speed of the first conveying member and the rotation speed of the second conveying member can be changed; The driving device drives the developing device with a constant relative speed ratio between the rotation speed of the first conveying member and the rotation speed of the third conveying member.

2. First and second conveying members arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and conveying a developer so as to circulate the developer between the first conveying path and the second conveying path; A developing member arranged opposite to the first conveying path and supplied with a developer from the first conveying path; A third conveying path for accommodating a third conveying member that collects and conveys the developer remaining in the developing member to the second conveying path; A driving device that drives the relative speed ratio between the rotation speed of the developing member and the rotation speed of the second conveying member to be changeable, and drives the relative speed ratio between the rotation speed of the first conveying member and the rotation speed of the third conveying member to be constant; The driving device includes a clutch mechanism, and the clutch mechanism changes the relative speed ratio between the rotation speed of the developing member and the rotation speed of the second conveying member.

3. First and second conveying members arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and conveying a developer so as to circulate the developer between the first conveying path and the second conveying path; A developing member arranged opposite to the first conveying path and supplied with a developer from the first conveying path; A third conveying path for accommodating a third conveying member that collects and conveys the developer remaining in the developing member to the second conveying path; It is driven so that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member can be changed, and it is driven with the relative speed ratio among the rotational speed of the first conveying member, the rotational speed of the second conveying member, and the rotational speed of the third conveying member being constant. It has a driving device. The driving device includes a clutch mechanism, and the clutch mechanism changes the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member. A developing device.

4. First conveying members and second conveying members that are arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and convey a developer so as to circulate the developer between the first conveying path and the second conveying path. A developing member that is arranged to face the first conveying path and is supplied with a developer from the first conveying path. A third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus in the developing member to the second conveying path. It is driven so that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member can be changed, and it is driven with the relative speed ratio between the rotational speed of the developing member and the rotational speed of the first conveying member being constant, and it has a driving device that drives with the relative speed ratio between the rotational speed of the second conveying member and the rotational speed of the third conveying member being constant. The driving device includes a clutch mechanism, and the clutch mechanism changes the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member. A developing device.

5. First conveying members and second conveying members that are arranged in a first conveying path and a second conveying path formed vertically in the direction of gravity, and convey a developer so as to circulate the developer between the first conveying path and the second conveying path through a first communication port and a second communication port formed in a partition wall between the first conveying path and the second conveying path. A developing member that is arranged to face the first conveying path and is supplied with a developer from the first conveying path. A third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus in the developing member to the second conveying path. It has a driving device that is driven so that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member can be changed. The developing device drives such that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the first conveying member is always constant, and drives such that the relative speed ratio between the rotational speed of the second conveying member and the rotational speed of the third conveying member is constant.

6. A first conveying member and a second conveying member that are disposed in a first conveying path and a second conveying path formed vertically in the direction of gravity, and convey a developer so as to circulate the developer between the first conveying path and the second conveying path. A developing member disposed opposite to the first conveying path and supplied with a developer from the first conveying path. A third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus in the developing member to the second conveying path. A driving device that drives such that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member can be changed, and drives such that the relative speed ratio among the rotational speed of the developing member, the rotational speed of the first conveying member, and the rotational speed of the third conveying member is constant. The driving device includes a clutch mechanism, and the clutch mechanism changes the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member.

7. A first conveying member and a second conveying member that are disposed in a first conveying path and a second conveying path formed vertically in the direction of gravity, and convey a developer so as to circulate the developer between the first conveying path and the second conveying path through a first communication port and a second communication port formed in a partition wall between the first conveying path and the second conveying path. A developing member disposed opposite to the first conveying path and supplied with a developer from the first conveying path. A third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus in the developing member to the second conveying path. A driving device that drives such that the relative speed ratio between the rotational speed of the developing member and the rotational speed of the second conveying member can be changed. The driving device drives such that the relative speed ratio among the rotational speed of the developing member, the rotational speed of the first conveying member, and the rotational speed of the third conveying member is always constant.

8. The developing device includes a third conveying path that houses a third conveying member that collects and conveys the developer that has become surplus in the developing member to the second conveying path. Between the second conveying path and the third conveying path, a partition member having a predetermined height is formed. The developing device according to any one of claims 1 to 7.

9. An image forming apparatus comprising: the developing device according to any one of claims 1 to 8; and a latent image carrier disposed to face the developing device.

Images