Developing device and image-forming device

Abstract

To prevent developer that is equal to or more than a predetermined amount from being discharged in a developing device having a first conveyance member and a second conveyance member disposed vertically and adjacently.SOLUTION: A developing device has first and second conveyance members 82, 84 that are disposed in first and second vertically formed conveyance paths 62, 64 and convey developer so as to circulate the developer between the first conveyance path 62 and the second conveyance path 64, a development member 52, and a drive unit 120 that drives the first conveyance member 82 and the second conveyance member 84 by making constant their relative speed ratio, and drives them by changing the relative speed ratio between the rotational speed of the development member 52 and the rotational speeds of the first and second conveyance members 82, 84, and the first conveyance member 82 has a carry-out conveyance blade 102 in a direction of a slant in a direction opposite to that of a conveyance blade 96 of the first conveyance member 82 between a communicating opening 74 for sending developer that is pushed upward to the first conveyance path 62 and an exhaust port 76 for discharging the developer.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Patent Document 1 listed below discloses a developing container including a developing roll that transports toner to a development area where an electrostatic latent image is developed into a toner image, a developing roll housing section that houses the developing roll, a first stirring chamber arranged diagonally below the developing roll housing section, and a second stirring chamber that is adjacent to the developing roll housing section and arranged above the first stirring chamber; a first stirring member that is housed in the first stirring chamber and transports the toner in the first stirring chamber while stirring it in a predetermined first transport direction; and a second stirring member that is housed in the second stirring chamber and transports the toner in the second stirring chamber in a second transport direction opposite to the first transport direction. and a communication passage that connects the downstream end of the first agitating chamber in the first transport direction with the upstream end of the second agitating chamber in the second transport direction to transport the toner from the downstream end of the first agitating chamber in the first transport direction to the upstream end of the second agitating chamber in the second transport direction, the communication passage being located on the side farthest from the developing roll with respect to the rotation axis of the first agitating member, and the portion of the communication passage that contacts the second agitating chamber and is located closest to the developing roll is formed vertically below the axial center of the developing roll. This developing device further includes an accumulated developer transport member that agitates and transports the developer accumulated between the developing roll and the first agitating member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-175768 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to prevent a developer amount exceeding a predetermined amount from being discharged in a developing device having a first transport member and a second transport member arranged adjacent to each other in the vertical direction. [Means for solving the problem]

[0005] The developing device according to the first aspect is a first transport member and a second transport member disposed in a first transport path and a second transport path formed above and below the first transport path and configured to transport the developer so as to circulate the developer between the first transport path and the second transport path; a developing member disposed opposite the first transport path and receiving developer from the first transport path; a drive device that drives the first transport member and the second transport member while maintaining a constant relative speed ratio between them, and that drives the first transport member and the second transport member while changing the relative speed ratio between the rotation speed of the developing member and the rotation speed of the first transport member and the second transport member; The first transport member has an outlet transport blade, the inclination of which is opposite to that of the transport blade of the first transport member, located between a communication port that sends the developer pushed upward into the first transport path and a discharge port that discharges the developer to the outside.

[0006] A developing device according to a second aspect is the developing device according to the first aspect, wherein the drive device drives the developing member, the first transport member, and the second transport member using separate power sources.

[0007] A developing device according to a third aspect is the developing device of the first aspect, wherein the drive 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 speeds of the first transport member and the second transport member.

[0008] A developing device according to a fourth aspect is the developing device of the first aspect, the developing device has a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path, The drive device drives the first conveying member, the second conveying member, and the third conveying member while maintaining a constant relative speed ratio among the rotation speed of the first conveying member, the rotation speed of the second conveying member, and the rotation speed of the third conveying member.

[0009] A developing device according to a fifth aspect is the developing device according to any one of the first to fourth aspects, the developing device includes a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path; A partition member having a predetermined height is formed between the second transport path and the third transport path.

[0010] An image forming apparatus according to a sixth aspect includes the developing device according to any one of the first to fourth aspects, and a latent image carrier disposed opposite the developing device. [Effects of the Invention]

[0011] According to the first aspect, in a developing device having a first transport member and a second transport member arranged adjacent to each other in the vertical direction in the direction of gravity, it is possible to prevent more than a predetermined amount of developer from being discharged.

[0012] According to the second aspect, the rotational speeds of the developing member, the first transport member, and the second transport member can be rotated independently without depending on each other.

[0013] According to the third aspect, the developing member, the first transport member, and the second transport member can be rotated independently without their rotational speeds depending on each other, and it is possible to reduce the number of power sources compared to when the developing member and the second transport member are driven by separate power sources.

[0014] According to the fourth aspect, it is possible to recover in the second transport path an amount of developer that corresponds to the rotation speed of the first transport member, regardless of the rotation speed of the developing member.

[0015] According to the fifth aspect, it is possible to prevent the developer collected in the second transport path from returning to the third transport path.

[0016] According to the sixth aspect, in a developing device having a first transport member and a second transport member arranged adjacent to each other in the vertical direction in the direction of gravity, it is possible to prevent developer from being discharged in an amount greater than a predetermined amount. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a developing device according to an embodiment of the present invention, viewed from a direction in which the developing device extends. [Figure 3] 1 is a cross-sectional view of a developing device according to an embodiment of the present invention, as viewed from the front side; [Figure 4] FIG. 4(A) is a diagram showing an example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 4(B) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 5] FIG. 5(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 5(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 6] FIG. 6(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 6(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 7] FIG. 7(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 7(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 8] FIG. 8(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 8(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 9]FIG. 9(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 9(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. [Figure 10] FIG. 10(A) is a diagram showing another example of a driving method for a developing device according to an embodiment of the present invention, and FIG. 10(B) is a diagram showing yet another example of a driving method for a developing device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] 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, which contains an image forming section 14, a transfer device 16, a fixing device 18, and a paper feeder 20. A recording medium transport path 22 for transporting a recording medium such as paper is also formed within the image forming apparatus main body 12.

[0019] The image forming section 14 employs an electrophotographic system to form an image on a recording medium. The image forming section 14 has, for example, a plurality of, for example, four, image forming units 24. The four image forming units 24 form toner images of different colors, for example, yellow, magenta, cyan, and black.

[0020] Each image forming unit 24 has a photosensitive drum 26. The photosensitive drum 26 is an example of an image carrier, and rotates while holding a toner image to be transferred to a recording medium on its outer circumferential surface. Each image forming unit 24 also has a charging device 28 that charges the photosensitive drum 26, a developing device 30 that develops the charged latent image with developer, and a cleaning device 32 that cleans the photosensitive drum 26 after transfer. An optical writing device 48 that forms a latent image on the charged photosensitive drum 26 is also provided.

[0021] The transfer device 16 has an intermediate transfer belt 34. Toner images are primarily transferred from the photosensitive drums 26 onto the intermediate transfer belt 34 by a primary transfer member 36, and the primarily transferred toner images are secondarily transferred onto a recording medium by a secondary transfer member 38.

[0022] The intermediate transfer belt 34 is supported so as to be rotatable by a plurality of support members 40. Also, a backup member 42 is provided opposite the secondary transfer member 38.

[0023] The fixing device 18 fixes the toner image transferred onto the recording medium to the recording medium using, for example, heat and pressure.

[0024] The paper feeder 20 has a storage section 44 that stores stacked recording media, and a delivery member 46 that delivers the recording media stored in the storage section 44 toward the recording medium transport path 22 .

[0025] The recording medium transport path 22 transports the recording medium from the paper feed device 20 to between the secondary transfer member 38 and the backup member 42, then transports the recording medium further to the fixing device 18, and further transports the recording medium so that it is ejected outside the image forming device main body 12.

[0026] In the image forming device 10 configured as described above, the toner images formed on the outer peripheral surfaces of the photosensitive drums 26 are primarily transferred to the intermediate transfer belt 34, the toner images primarily transferred to the intermediate transfer belt 34 are secondarily transferred to a recording medium, and the toner images secondarily transferred to the recording medium are fixed to the recording medium by the fixing device 18.

[0027] Next, referring to FIG. 2, a developing device 30 according to this embodiment will be described. This device is a two-component developing device that agitates a developer composed of a carrier and toner, charging the toner, and developing the toner. In the following description, the direction above the direction of gravity will be referred to as "up," the direction below the direction of gravity will be referred to as "down," and when no distinction is made between "up" and "down," the direction above and below the direction of gravity will be referred to as "up and down" or simply "up and down." Furthermore, the direction perpendicular to the direction above and below the direction of gravity and along which the developing roll 52, first transport member 82, second transport member 84, and other components described below extend will be referred to as the "axial direction." Furthermore, for convenience, the side of the first transport path 62 on which a developer supply port 70 (described later) is formed, i.e., the left side of the drawing in FIG. 3, will be referred to as the "supply end" side, and the side of the second transport path 64 on which a lower discharge port 80 (described later) is formed, i.e., the right side of the drawing, will be referred to as the "discharge end" side.

[0028] The developing device 30 is disposed opposite the photosensitive drum 26, which serves as an image carrier. The developing device 30 has a developing device main body 50 in the form of a developing device housing. A developing roll 52, which serves as a developing member, is disposed within the developing device main body 50, facing the photosensitive drum 26. The developing roll 52 includes a magnet roll 54 for generating 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 within the developing sleeve 56. The developing sleeve 56 is rotatably supported by a cylindrical member made of a non-magnetic material relative to the developing device main body 50. A layer thickness regulating member 58, which regulates the thickness of the developer layer, is fixed to the developing device main body 50 above the developing roll 52 and faces 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 thickness by a layer thickness regulating member 58, and then moved to the latent image formed on the photosensitive drum 26.

[0029] The developing device main body 50 is divided by a partition wall 60 that divides its interior into upper and lower sections in the direction of gravity, and a first transport path 62 and a second transport path 64 are provided, each formed on the upper and lower sections in the direction of gravity. The upper surface of the partition wall 60, which has an arc-shaped cross section, forms the lower surface of the first transport path 62. The lower surface of the partition wall 60, which has an arc-shaped cross section, forms the upper surface of the second transport path 64. The first transport path 62 and the second transport path 64 have the same axial length and extend in the axial direction. The developing roll 52 is disposed opposite a developer supply port 66 formed in the first transport path 62 along the axial direction, and developer is supplied from the first transport path 62.

[0030] As shown in FIG. 3, the top surface 68 of the developing device main body 50 is also the top surface of the first transport path 62, and a developer supply port 70 is provided on the supply end side of a portion corresponding to the upper part of the first transport path 62. A first communication port 72 is formed in a portion of the partition wall 60 below the developer supply port 70 in the direction of gravity. The partition wall 60 is further provided with a second communication port 74 on the discharge end side of the first communication port 72. The partition wall 60 is also provided with an upper discharge port 76 in a portion closer to the discharge end side. The bottom surface 78 of the developing device main body 50 is also the bottom surface of the second transport path 64, and a lower discharge port 80 is formed in a portion closest to the discharge end side.

[0031] A first transport member 82 and a second transport member 84 are rotatably arranged in the first transport path 62 and the second transport path 64, respectively, to agitate and circulate the developer between the first transport path 62 and the second transport path 64.

[0032] 2, a third transport path 86 is provided obliquely below the developing roll 52 in the direction of gravity to return and collect excess developer from the developing roll 52 to the second transport path 64. A third transport member 88 is rotatably disposed in the third transport path 86.

[0033] As shown in FIG. 3 , the first conveying member 82, the second conveying member 84, and the third conveying member 88 have axial centers 90, 92, and 94, respectively. The supply end side of the axial center 90 of the first conveying member 82 is journaled by a first upper-stage bearing B1 at the upper part of the supply end side of the developing device main body 50, and the discharge end side is journaled by a second upper-stage 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 journaled by a first lower-stage bearing B3 at the lower part of the supply end side of the developing device main body 50, and the discharge end side is journaled by a second lower-stage bearing B4 at the lower part of the supply end side of the developing device main body 50. Here, the second upper-stage bearing B2, which supports the discharge end side of the axial center 90 of the first conveying member 82, and the second lower-stage bearing B4, which supports the discharge end side of the axial center 92 of the second conveying member 84, are positioned in the same axial direction.

[0034] The first conveying member 82, the second conveying member 84, and the third conveying member 88 are provided with conveying blades 96, 98, and 100 that are spirally shaped around axial centers 90, 92, and 94, respectively, and are inclined in the same direction.

[0035] The conveying blades 96 of the first conveying member 82 are formed around an axial center 90 between the first communication port 72 and the second communication port 74. The conveying blades 98 of the second conveying member 84 are also formed around an axial center 92 between the first communication port 72 and the second communication port 74.

[0036] Furthermore, the first conveying member 82 is provided, in a portion between the second communication port 74 and the upper discharge port 76, with a discharge conveying blade 102 whose blade is inclined in the opposite direction to the conveying blade 96, an adjustment blade 104 whose blade is inclined in the same direction as the conveying blade 96, and an upper discharge blade 106 whose blade is inclined in the same direction as the discharge conveying blade 102 and whose blade length in the radial direction is shorter. The discharge conveying blade 102 is formed so that a portion of the blade overlaps the second communication port 74. The upper discharge blade 106 is disposed in an upper discharge space 108 whose diameter in the vertical and width directions is smaller than that of the first conveying path 62, and 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.

[0037] Further, the second transport member 84 is provided, in a portion between the second communication port 74 and the lower discharge port 80, with a developer return blade 110 whose blade is inclined in the opposite direction to the transport blade 98, and a lower discharge blade 112 whose blade is inclined in the same direction as the transport blade 98. The lower discharge blade 112 is disposed in a lower discharge space 114 whose diameter in the vertical and width directions is smaller than that of the second transport path 64, and which is formed between a downwardly protruding portion of the partition wall 60 and an upwardly protruding portion of the bottom surface of the second transport path 64.

[0038] With the above configuration, the developer supplied from the developer supply port 70 falls downward in the direction of gravity through the first transport path 62 and is supplied to the second transport path 64 through the first communication port 72, and is then transported by the second transport member 84 through the second transport path 64 toward the discharge end until it reaches a position near the bottom of the second communication port 74. The developer transported to a position near the bottom of the second communication port 74 is prevented from being transported toward the discharge end by the developer return blade 110, and collides with developer further transported from the supply end side of the second transport path 64. As a result, the developer near the bottom of the second communication port 74 is pushed upward in the direction of gravity and sent into the first transport path 62 through the second communication port 74.

[0039] The developer sent into the first transport path 62 is transported by the transport blades 96 of the first transport member 82 in the direction of the first communication port 72, i.e., toward the supply end, and is supplied from the developer supply port 66 onto the developing roll 52. The developer that remains in the first transport path 62 without being supplied to the developing roll 52 is transported by the first transport member 82 in the direction of the supply end to the first communication port 74, then falls downward in the direction of gravity at the first communication port 74 and is supplied again to the second transport path 64, repeating the circulation described above.

[0040] Furthermore, a portion of the developer sent from the second transport path 64 into the first transport path 62 through the second communication port 74 is transported toward the discharge end by the discharge transport blade 102, and is further pushed back toward the supply end by the adjustment blade 104 so that more than a predetermined amount of developer is not discharged. Excess developer that is not returned toward the supply end by the adjustment blade 104 is transported through the upper discharge space 108 toward the discharge end by the upper discharge blade 106, falls downward in the direction of gravity through the upper discharge port 76, and is discharged into the lower discharge space 114 of the second transport path 64. The excess developer discharged into the lower discharge space 114 is further transported toward the discharge end by the lower discharge blade 112, and is finally discharged from the lower discharge port 80 to the outside of the developing device main body 50.

[0041] In this way, the upper discharge outlet 76, the lower discharge outlet 80, the discharge conveying blade 102, the adjustment 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 excess developer discharged from the first conveying path 62 to the outside through the second conveying path 64.

[0042] On the other hand, of the developer supplied from the first transport path 62 onto the developing roll 52, any surplus developer that remains after development is completed is peeled off from the developing roll 52 toward the third transport path 86, and is further recovered and transported from the third transport path 86 to the second transport path 64, where it is mixed and stirred by the second transport member 84 together with new developer supplied from a developer supply device (not shown).As shown by the arrow in Figure 3, this surplus developer is pushed up from the second communication port 74 to the first transport path 62 at the discharge end of the developing device main body 50, and is then supplied again onto the developing roll 52 by the first transport member 82, creating a flow of developer.

[0043] Here, the positional relationship between the developing roll 52, the second transport member 84, and the third transport member 88 will be described. As shown in Fig. 2, the axial center 92 of the second transport member 84 is disposed higher in the direction of gravity than the third transport member 88. The axial centers 92 of the second transport member 84 and 94 of the third transport member 88 are both disposed lower in the direction of gravity than the axial center of the developing roll 52. The axial center 90 of the first transport member 82 is disposed higher in the direction of gravity than the axial center of the developing roll 52.

[0044] Therefore, because the diameter of the third conveying member 88 is smaller than the diameter 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 either 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. Note that in this embodiment, an example is described in which 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 direction of gravity, but by appropriately selecting the diameters of the second conveying member 84 and the third conveying member 88, 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 lower in the direction of gravity, as long as the bottom surfaces of the second conveying path 64 and the third conveying path 86 are at the same height.

[0045] Furthermore, a partition member 116 of a predetermined height is formed between the second transport path 64 and the third transport path 86. This partition member 116 is a plate-shaped wall surface that protrudes upward in the direction of gravity from near the gap between the bottom surfaces of the second transport path 64 and the third transport path 86, and extends along the axial direction. An upper end 118 of this partition member 116 is located above, in the direction of gravity, an imaginary line connecting the axial center 92 of the second transport member 84 and the axial center 94 of the third transport member 88. The height of this partition member 116 in the direction of gravity may be any height that allows the third transport member 88 to transport the developer from the third transport path 86 to the second transport path 64 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.

[0046] Furthermore, the partition member 116 between the second transport path 64 and the third transport path 86 allows developer to be transported from the third transport path 86 to the second transport path 64 by the third transport member 88, while functioning as a return prevention member that can prevent or block developer transported from the third transport path 86 to the second transport path 64 from returning to the third transport path 86 again. Any member that allows developer to flow in one direction, such as a plate body with a free end upward in the direction of gravity or an opening formed in the partition member 116, can be used.

[0047] Next, with reference to FIGS. 4A and 4B, a description will be given of the drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In FIG. 3A, the developing device 30 has a drive device 120 that drives the developing roll 52 and the second transport member 84 by changing the relative speed ratio between their rotational speeds. This drive device 120 drives at least the developing roll 52 and the second transport member 84 by separate power sources, and includes a first power source M1 and a second power source M2. In other words, the developing roll 52 is driven by the first power source M1, while the second transport member 84 is driven by the second power source M2.

[0048] Therefore, these independent first power source M1 and second power source M2 drive the developing roll 52 and the second conveying member 84 in a state in which the relative speed ratio between the rotational speed of the developing roll 52 and the rotational speed of the second conveying member 84 can be changed independently of each other.

[0049] 4(B), the driving device 120 may have clutch mechanisms C1 and C2. In FIG. 4(B), the developing roll 52 and the second transport 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 between the rotational speeds of the developing roll 52 and the second transport member 84 can be changed independently.

[0050] 5A and 5B show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120A shown in FIG. 5A, the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, respectively, similar to FIG. 4A. Additionally, the first transport member 82 and the second transport member 84 are driven by the same power source M2. This maintains a constant rotational speed ratio between the first transport member 82 and the second transport member 84. Meanwhile, the rotational speed ratio between the developing roll 52, driven by the first power source M1, and the first and second transport members 82 and 84, driven by the second power source M2, are driven in a changeable manner independent of each other.

[0051] 5(B), the driving device 120A drives the developing roll 52, the first transport member 82, and the second transport 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 transport member 82 and the second transport member 84. By using the clutch mechanisms C1 and C2, the rotational speed ratio of the developing roll 52 and the rotational speed ratio of the first transport member 82 and the second transport member 84 can be changed independently.

[0052] 6A and 6B show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120B shown in FIG. 6A, the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, respectively, similar to FIG. 4A. Additionally, the first transport member 82, the second transport member 84, and the third transport member 88 are driven by the same power source M2. This ensures that the rotational speed ratio between the first transport member 82, the second transport member 84, and the third transport member 88 is constant. Meanwhile, the rotational speed ratio between the developing roll 52 driven by the first power source M1 and the first transport member 82, the second transport member 84, and the third transport member 88 driven by the second power source M2 is variable and independent of one another.

[0053] 6(B), the driving device 120B drives the developing roll 52, the first transport member 82, the second transport member 84, and the third transport 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 clutch mechanism C2 is disposed between the power source M3 and the first transport member 82, the second transport member 84, and the third transport member 88. By using the clutch mechanisms C1 and C2, the rotational speed ratio of the developing roll 52 and the rotational speed ratio of the first transport member 82, the second transport member 84, and the third transport member 88 can be changed independently.

[0054] 7A and 7B show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120C shown in FIG. 7A, the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, respectively, similar to FIG. 4A. In addition, the developing roll 52 and the first transport member 82 are driven by the same power source M1. This maintains a constant rotational speed ratio between the developing roll 52 and the first transport member 82. Meanwhile, the rotational speed ratio between the developing roll 52 and the first transport member 82, driven by the first power source M1, and the rotational speed ratio between the second transport member 84, driven by the second power source M2, are driven in a changeable manner independent of each other.

[0055] 7(B), the driving device 120C drives the developing roll 52, the first transport member 82, and the second transport 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 transport member 82, and the clutch mechanism C2 is disposed between the power source M3 and the second transport member 84. By using the clutch mechanisms C1 and C2, the rotational speed ratio between the developing roll 52 and the first transport member 82 and the rotational speed ratio of the second transport member 84 can be changed independently.

[0056] 8A and 8B show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120D shown in FIG. 8A, the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, respectively, similar to FIG. 4A. In addition, the developing roll 52 and the first transport member 82 are driven by the same power source M1, and the second transport member 84 and the third transport member 88 are driven by the same power source M2. This ensures that the rotational speed ratio between the developing roll 52 and the first transport member 82 is constant, and that the rotational speed ratio between the second transport member 84 and the third transport member 88 is also constant. On the other hand, the rotational speed ratio between the developing roll 52 and the first conveying member 82 driven by the first power source M1 and the rotational 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 changeable state independent of each other.

[0057] 8(B), the driving device 120D drives the developing roll 52, the first transport member 82, the second transport member 84, and the third transport 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 transport member 82, and the clutch mechanism C2 is disposed between the power source M3 and the second transport member 84 and the third transport member 88. By using the clutch mechanisms C1 and C2, the rotational speed ratio between the developing roll 52 and the first transport member 82 and the rotational speed ratio between the second transport member 84 and the third transport member 88 can be changed independently.

[0058] 9(A) and 9(B) show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120E shown in FIG. 9(A), the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, similar to FIG. 4(A). In addition, the developing roll 52, the first transport member 82, and the third transport member 88 are driven by the same power source M1, and only the second transport member 84 is driven by a separate power source M2. This ensures that the rotational speed ratio between the developing roll 52, the first transport member 82, and the third transport member 88 is constant. On the other hand, the rotational speed ratio between the developing roll 52, the first conveying member 82, and the third conveying member 88 driven by the first power source M1 and the rotational speed ratio between the second conveying member 84 driven by the second power source M2 are driven in a changeable state independent of each other.

[0059] 9(B), the driving device 120E drives the developing roll 52, the first transport member 82, the second transport member 84, and the third transport 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 transport member 82, and the third transport member 88, and the clutch mechanism C2 is disposed between the power source M3 and the second transport member 84. By using the clutch mechanisms C1 and C2, the rotational speed ratio of the developing roll 52, the first transport member 82, and the third transport member 88 and the rotational speed ratio of the second transport member 84 can be changed independently.

[0060] 10(A) and 10(B) show another example of a drive system for the developing roll 52, first transport member 82, second transport member 84, and third transport member 88 in the developing device 30 configured as described above. In the drive device 120F shown in FIG. 10(A), the developing roll 52 and the second transport member 84 are driven by separate power sources M1 and M2, respectively, similar to FIG. 4(A). In addition, the first transport member 82 and the third transport member 88 are driven by yet another identical power source M3. This allows the rotational speed ratio between the first transport member 82 and the third transport member 88 to be constant. On the other hand, the rotational speed ratio of the developing roll 52 driven by the first power source M1, the rotational speed ratio of the second conveying member 84 driven by the second power source M2, and the rotational speed ratio of the first conveying member 82 and the third conveying member 88 driven by the third power source M3 are driven in a changeable state independent of each other.

[0061] 10(B), the driving device 120F drives the developing roll 52, the first transport member 82, the second transport member 84, and the third transport member 88 via clutch mechanisms C1, C2, and C3 using the same power source M4. 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 transport member 84, and the clutch mechanism C3 is disposed between the power source M4 and the first transport member 82 and the third transport member 88. By using the clutch mechanisms C1, C2, and C3, the rotational speed of the developing roll 52, the rotational speed of the second transport member 84, and the ratio of the rotational speeds of the first transport member 82 and the third transport member 88 can be changed independently.

[0062] 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, and are disposed inside the image forming apparatus main body 12, and are controlled and driven by a control device (not shown) that controls the operation of each part of the image forming apparatus 10. The control device includes a CPU, memory, storage device, and communication interface (not shown). The CPU is a control microprocessor that controls the operation of each part of the image forming apparatus based on a control program stored in the storage device.

[0063] In each of the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0064] Furthermore, the operations of the processor in each of the above embodiments may be performed not only by a single processor but also by multiple processors located at physically separate locations working together. Furthermore, the order of the operations of the processor is not limited to the order described in each of the above embodiments and may be changed as necessary.

[0065] (Addendum) (((1))) a first transport member and a second transport member disposed in a first transport path and a second transport path formed above and below the first transport path and configured to transport the developer so as to circulate the developer between the first transport path and the second transport path; a developing member disposed opposite the first transport path and receiving developer from the first transport path; a drive device that drives the first transport member and the second transport member while maintaining a constant relative speed ratio between the rotation speed of the first transport member and the rotation speed of the second transport member, and that drives the first transport member and the second transport member while changing the relative speed ratio between the rotation speed of the developing member and the rotation speed of the first transport member and the second transport member, A developing device in which the first transport member has an outlet transport blade, the inclination of which is opposite to that of the transport blade of the first transport member, located between a communication port that sends the developer pushed upward into the first transport path and a discharge port that discharges the developer to the outside. (((2))) The developing device according to (((1))), wherein the drive device drives the developing member, the first transport member, and the second transport member using separate power sources. (((3))) The developing device described in (((1))), wherein the drive 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 speeds of the first transport member and the second transport member. (((4))) the developing device has a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path, The developing device described in (((1)))), wherein the drive device drives the developing device while maintaining a constant relative speed ratio between the rotational speed of the first transport member, the rotational speed of the second transport member, and the rotational speed of the third transport member. (((5))) the developing device includes a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path; The developing device according to any one of ((1))) to ((4))), wherein a partition member of a predetermined height is formed between the second transport path and the third transport path. (((6))) An image forming apparatus comprising: a developing device according to any one of claims ((1)) to ((5)); and a latent image carrier disposed opposite the developing device.

[0066] According to the developing device of (((1))), in a developing device having a first transport member and a second transport member arranged adjacent to each other above and below in the direction of gravity, it is possible to prevent more than a predetermined amount of developer from being discharged. According to the developing device of (((2))), the rotational speeds of the developing member, the first transport member, and the second transport member can be rotated independently without depending on each other. According to the developing device of (((3))), the developing member, the first transport member, and the second transport member can be rotated independently without their rotational speeds depending on each other, and it is possible to reduce the number of power sources compared to when the developing member and the second transport member are driven by separate power sources. According to the developing device of (((4))), it is possible to collect the amount of developer corresponding to the rotation speed of the first transport member into the second transport path, regardless of the rotation speed of the developing member. According to the developing device of (((5))), it is possible to prevent the developer collected in the second transport path from returning to the third transport path. According to the image forming apparatus of (((6))), in a developing device having a first conveying member and a second conveying member arranged adjacent to each other above and below in the direction of gravity, it is possible to prevent more than a predetermined amount of developer from being discharged. [Explanation of symbols]

[0067] 10 Image forming device 12 Image forming device main body 14 Image forming section 16 Transcription device 18 Fixing device 20 Paper feeder 22 Recording medium transport path 24 Image forming unit 24 Each image forming unit 26 Photosensitive drum 28 Charging device 30 Developing device 32 Cleaning equipment 34 Intermediate transfer belt 36 Primary transfer member 38 Secondary transfer member 40 Support member 42 Backup member 44 Storage area 46 Delivery member 48 Optical writing device 50 Developing device body 52 Developing roll 54 Magnet Roll 56 Developing sleeve 58 Layer thickness control member 60 Partition Wall 62 First conveying path 64 Second transport path 66 Developer supply port 68 Top 70 Developer supply port 72 First communication port 74 Second communication port 76 Upper discharge port 78 bottom 80 Lower discharge port 82 first conveying member 84 second conveying member 86 Third Transport Path 88 third conveying member 90, 92, 94 axis center 96, 98 Conveying blades 102 Discharge conveying blade 104 Adjustable blade 106 Upper discharge blade 108 Upper discharge space 110 Developer return blade 112 Lower discharge blade 114 Lower discharge space 116 Partition member 118 Top 120, 120A-120F drive unit B1, B2 upper bearing B3, B4 lower bearing C, C1-C3 clutch mechanism M1-M4 power source

Claims

1. a first transport member and a second transport member disposed in a first transport path and a second transport path formed above and below the first transport path and configured to transport the developer so as to circulate the developer between the first transport path and the second transport path; a developing member disposed opposite the first transport path and receiving developer from the first transport path; a drive device that drives the first transport member and the second transport member while maintaining a constant relative speed ratio between the rotation speed of the first transport member and the rotation speed of the second transport member, and that drives the first transport member and the second transport member while changing the relative speed ratio between the rotation speed of the developing member and the rotation speed of the first transport member and the second transport member, A developing device in which the first transport member has an outlet transport blade, the inclination of which is opposite to that of the transport blade of the first transport member, located in a portion between a communication port that sends the developer pushed upward into the first transport path and a discharge port that discharges the developer to the outside.

2. 2. The developing device according to claim 1, wherein said driving device drives said developing member, said first transport member and said second transport member by separate power sources.

3. 2. The developing device according to claim 1, wherein the drive device includes a clutch mechanism that changes a relative speed ratio between the rotational speed of the developing member and the rotational speeds of the first and second transport members.

4. the developing device has a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path, 2. The developing device according to claim 1, wherein the drive device drives the first transport member, the second transport member, and the third transport member at a constant relative speed ratio.

5. the developing device includes a third transport path that accommodates a third transport member that collects and transports excess developer from the developing member to the second transport path; 5. The developing device according to claim 1, further comprising a partition member having a predetermined height between the second transport path and the third transport path.

6. An image forming apparatus comprising: the developing device according to claim 1; and a latent image carrier disposed opposite the developing device.

Images