Developing unit and image formation device

Abstract

To enable stable supply of developer to a developer holding body with a simple structure even when the consumption of developer increases, unlike the situation where the amount of developer is made to increase by control when the consumption of the developer containing toner and carrier increases.SOLUTION: Provided is a developing unit comprising: a developer holding body that holds developer, which contains toner and carrier, to be supplied to an image holding body that forms an electrostatic latent image; and conveyance means 337 for stirring and conveying, with a rotary member 52, the developer that flows in from an inflow port 54 and flows out toward the developer holding body at an outflow port 55. The conveyance means 337 comprises a first blade portion 52a, as a portion forming part of the rotary member 52, that conveys the developer to the outflow port 55 and a second blade portion 52b for conveying the developer in a direction 50d opposite to the outflow port 55. The amount of developer that flows in from the inflow port 54 is larger than the amount of developer that flows out from the outflow port 55.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] For example, Patent Document 1 discloses a developer carrying body that carries developer including toner and magnetic carriers, a developer container that extends in a direction parallel to the axial direction of the developer carrying body and contains developer to be supplied to the developer carrying body, a partition portion that divides the inside of the developer container into a first transport space and a second transport space and extends in a direction parallel to the axial direction so as to enable delivery of developer between the first transport space and the second transport space from both ends, a stirring and transporting member that stirs and transports the developer to circulate the developer between the first transport space and the second transport space, and a flow rate adjusting portion that adjusts the flow rate of the developer circulating between the first transport space and the second transport space. a developer container including a first portion corresponding to a developer carrier and a second portion protruding from the first portion in a direction parallel to the axial direction, a partition portion of the portion located in the second portion is provided with an opening portion that connects the first transport space and the second transport space and circulates the developer within the second portion, the second transport space has a region facing the opening portion and an adjacent region adjacent to the region on the downstream side in the transport direction in which the stirring transport member transports the developer, and a flow rate adjustment portion adjusts the amount of developer passing through the adjacent region in accordance with fluctuations in the amount of toner, thereby adjusting the flow rate of the developer circulating within the second portion through the opening portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-159810 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, the amount of developer, which includes toner and carrier, in the developing device fluctuates depending on the amount of toner consumed, etc. When the amount of developer fluctuates, the charge amount of the toner and the amount of developer supplied to the developer holder become unstable, which may lead to quality degradation such as uneven image density, so a stable supply of developer to the developer holder is required even when the amount of developer fluctuates. For this reason, when the amount of toner consumed increases, a configuration can be considered in which the amount of developer in the developing device is increased by control using the detection result of a detection means, for example, to achieve a stable supply. However, adopting such a configuration would make the configuration complicated. The object of the present invention is to enable a stable supply of developer to a developer holder with a simple configuration even when the consumption of developer containing toner and carrier increases, compared to a case in which the amount of developer is increased by control when the consumption of developer increases. [Means for solving the problem]

[0005] The invention described in claim 1 is a developing device comprising: a developer holder that holds a developer containing toner and a carrier, the developer being supplied to an image holder that forms an electrostatic latent image; and a transport means that uses a rotating member to stir and transport the developer flowing in from an inlet and discharge it toward the developer holder at an outlet, the transport means including, as a part constituting a part of the rotating member, a first blade portion that transports the developer to the outlet and a second blade portion that transports the developer in the opposite direction to the outlet, and a greater amount of developer flows in from the inlet than flows out from the outlet. The invention described in claim 2 is the developing unit described in claim 1, characterized in that an end of the first blade portion farther from the outlet is located in an area corresponding to a width of the inlet. The invention described in claim 3 is the developing device described in claim 2, characterized in that the far end is located on the side farther from the outflow outlet when the area is divided in half at the widthwise center of the inflow inlet. The invention described in claim 4 is the developing device described in claim 2, characterized in that the distant end is located on the side closer to the outlet when the area is divided in half at the widthwise center of the inlet. The invention described in claim 5 is the developing device described in claim 1, characterized in that the developer flowing into the inlet is transported by a transport path formed by a rotating member other than the rotating member of the transport means, and the direction in which the developer is transported by the other rotating member is the same as the direction in which the developer is transported by the rotating member. The invention described in claim 6 is the developing unit described in claim 1, characterized in that the developer flowing into the inlet is transported by a transport path provided by a rotating member other than the rotating member of the transport means, and the transport force of the other rotating member is higher than that of the first blade portion. The invention described in claim 7 is the developing device described in claim 6, characterized in that the strength of the transport force is determined by at least one of the pitch of the blade, the radius of the blade, and the rotation speed during transport. An eighth aspect of the present invention is the developing unit according to the fifth or sixth aspect, characterized in that the developer transported by the second blade portion can be discharged. The invention described in claim 9 is an image forming apparatus including an image holder that forms an electrostatic latent image, a developing means that develops the electrostatic latent image formed on the image holder into a toner image, a transfer means that transfers the toner image by the developing means onto a recording material, and a fixing means that fixes the toner image transferred onto the recording material to the recording material, wherein the developing means is a developer holder that holds a developer containing toner and a carrier and is supplied to the image holder that forms an electrostatic latent image, and a transport means that stirs and transports the developer flowing in from an inlet using a rotating member and flows it out toward the developer holder at an outlet, the transport means having a first blade portion that transports the developer to the outlet and a second blade portion that transports the developer in the opposite direction to the outlet as a part that constitutes a part of the rotating member, and a greater amount of developer flows in from the inlet than flows out from the outlet. Effect of the Invention

[0006] According to the invention of claim 1, compared to a case where the amount of developer is increased by control when the consumption of developer containing toner and carrier increases, a stable supply of developer to the developer holder is possible with a simple configuration even when the consumption of developer increases. According to the invention of claim 2, the end of the first blade portion farther from the outlet can prevent excess or deficiency of developer being transported to the outlet compared to a case in which the end is not configured to be located in an area corresponding to the width of the inlet. According to the invention of claim 3, the far end can increase the amount of developer transported to the outlet compared to a case in which the far end is not provided with a configuration located on the far side from the outlet when the area is divided in half at the center of the width at the inlet. According to the invention of claim 4, the amount of developer transported to the outlet can be prevented from becoming excessive, compared to a case in which the far end is not provided with a configuration located on the side closer to the outlet when the area is divided in half at the center of the width at the inlet. According to the invention of claim 5, the direction in which the transport is performed by the other rotating member can utilize inertial force for transport by the rotating member, compared to a case in which the configuration is not provided in which the direction in which the transport is performed by the rotating member is the same as the direction in which the transport is performed by the other rotating member. According to the invention of claim 6, the transport force of the other rotating member is higher than that of the first blade portion, so that the developer can be supplied to the developer holder more stably than in a case where the configuration is not provided. According to the seventh aspect of the present invention, the design conditions of the developing unit can be relaxed. According to the eighth aspect of the present invention, it is possible to prevent the amount of developer from becoming excessive. According to the invention of claim 9, compared to a case where the amount of developer containing toner and carrier is increased by control when the consumption of developer increases, a stable supply of developer to the developer holder is possible with a simple configuration even when the consumption of developer increases. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an image forming apparatus. [Diagram 2] FIG. 2 is a schematic front view illustrating a developing unit of the image forming apparatus. [Diagram 3] FIG. 2 is a schematic plan view illustrating a developing unit of the image forming apparatus. [Figure 4] 11A and 11B are diagrams illustrating a conveying force by a blade portion and a relationship between the conveying force by the blade portion. [Diagram 5] 5A and 5B are diagrams for explaining the position of the blade portion relative to the inlet, where (a) shows one example and (b) shows another example. [Figure 6] FIG. 2 is a diagram illustrating a developing unit according to the first embodiment. [Figure 7] FIG. 11 is a diagram illustrating a developing unit according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an image forming apparatus 1. As shown in FIG. The image forming apparatus 1 according to this embodiment includes a paper feed unit 1A, a printing unit 1B, and a paper discharge unit 1C. The paper feed unit 1A includes a first paper storage section 11 to a fourth paper storage section 14 for storing paper P as an example of a recording medium. The paper feed unit 1A also has feed rolls 15-18 that correspond to the first paper storage section 11 to the fourth paper storage section 14, respectively, and feed the paper P stored in each paper storage section to a transport path connected to the printing unit 1B.

[0009] The printing unit 1B includes an image forming section 20 that forms an image on a sheet P. The printing unit 1B also includes a control section 21 that controls each section of the image forming apparatus 1. The printing unit 1B also includes an image processing section 22. The image processing section 22 performs image processing on image data transmitted from the image reading device 4 and the personal computer (PC) 5. The printing unit 1B is also provided with a UI (User Interface) 23, which is configured with a touch panel or the like and notifies the user of information and receives information input from the user.

[0010] Image forming section 20, as an example of an image forming means, is provided with six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as "image forming units 30") arranged in parallel at regular intervals. Each image forming unit 30 includes a photosensitive drum 31 on which an electrostatic latent image is formed while rotating in the direction of arrow A, a charging roll 32 which charges the surface of the photosensitive drum 31, a developing device 33 which develops the electrostatic latent image formed on the photosensitive drum 31, and a drum cleaner 34 which removes toner and the like from the surface of the photosensitive drum 31. The photoconductor drum 31 is an example of an image carrier.

[0011] The image forming section 20 is also provided with a laser exposure device 26 that exposes the photoconductor drum 31 of each image forming unit 30 to laser light. The exposure of the photoconductor drum 31 by the laser exposure device 26 is not limited to using laser light. For example, a light source such as an LED (Light Emitting Diode) may be provided for each image forming unit 30, and the photoconductor drum 31 may be exposed using light emitted from the light source.

[0012] Each image forming unit 30 is configured similarly, except for the toner contained in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Further, the image forming units 30T and 30P form toner images using toner corresponding to a corporate color, foaming toner for Braille, fluorescent color toner, toner for improving gloss, etc. In other words, the image forming units 30T and 30P form toner images using toner of a special color.

[0013] The image forming section 20 is also provided with an intermediate transfer belt 41 onto which the toner images of each color formed on the photosensitive drums 31 of the image forming units 30 are transferred. The image forming section 20 is also provided with a primary transfer roll 42 that transfers the respective color toner images of the respective image forming units 30 onto the intermediate transfer belt 41 at a primary transfer portion T1. The image forming unit 20 is also provided with a secondary transfer roll 40 that transfers the toner image transferred onto the intermediate transfer belt 41 onto the paper P at a secondary transfer portion T2. Furthermore, the image forming section 20 is provided with a belt cleaner 45 that removes toner and the like from the surface of the intermediate transfer belt 41, and a fixing device 80 that fixes the secondarily transferred image onto the paper P. The developing device 33 is an example of a developing unit, the intermediate transfer belt 41 is an example of a transfer unit, and the fixing device 80 is an example of a fixing unit.

[0014] The image forming unit 20 performs an image forming operation based on a control signal from the control unit 21 . Specifically, in the image forming unit 20, first, image processing is performed on the image data input from the image reading device 4 or the PC 5 by the image processing unit 22, and the image data after image processing is supplied to the laser exposure device 26. Then, for example, in a magenta (M) image forming unit 30M, the surface of the photosensitive drum 31 is charged by the charging roll 32, and then the laser exposure device 26 irradiates the photosensitive drum 31 with laser light modulated by image data obtained from the image processing unit 22.

[0015] As a result, an electrostatic latent image is formed on the photoconductor drum 31 . The formed electrostatic latent image is developed by the developing unit 33, and a magenta toner image is formed on the photosensitive drum 31. Similarly, yellow, cyan and black toner images are formed in the image forming units 30Y, 30C and 30K, and special color toner images are formed in the image forming units 30T and 30P.

[0016] The respective color toner images formed in each image forming unit 30 are electrostatically transferred sequentially by a primary transfer roll 42 onto an intermediate transfer belt 41 rotating in the direction of arrow C in Figure 1, and superimposed toner images are formed on the intermediate transfer belt 41. The superimposed toner image formed on the intermediate transfer belt 41 is transported to a secondary transfer portion T2 constituted by a secondary transfer roll 40 and a backup roll 49 as the intermediate transfer belt 41 moves.

[0017] On the other hand, the paper P is taken out from the first paper storage unit 11 by, for example, the delivery roll 15, and then transported to the position of the registration roll 74 via the transport path. When the superimposed toner image is transported to the secondary transfer portion T2, a sheet of paper P is supplied from the registration roll 74 to the secondary transfer portion T2 in accordance with the transport timing. Then, in the secondary transfer portion T2, the superimposed toner images are electrostatically transferred onto the paper P all at once by the action of a transfer electric field formed between the secondary transfer roll 40 and the backup roll 49.

[0018] Thereafter, the paper P onto which the superimposed toner images have been electrostatically transferred is transported to a fixing device 80. In the fixing device 80, pressure and heat are applied to the paper P on which the unfixed toner image has been formed, and the toner image is fixed to the paper P. Then, the sheet P on which the fixing process has been performed passes through a curl correction section 81 provided in the sheet discharge unit 1C, and is then conveyed to a sheet stacking section (not shown).

[0019] 2 and 3 are diagrams illustrating the developing unit 33 of the image forming apparatus 1, where FIG. 2 is a schematic front view of the developing unit 33 as viewed from the same direction as shown in FIG. 1, and FIG. 3 is a schematic plan view of the developing unit 33 as viewed from above. 2, the developing unit 33 includes a storage unit 331 that stores a developer (not shown) therein. The storage unit 331 is made of a resin storage case 332. The developer is made of a magnetic carrier and a colored toner, and is a so-called two-component developer. The housing 332 of the developing device 33 is arranged to extend along a direction perpendicular to the paper surface of FIG. 2, which is the direction from the front side to the rear side of the image forming apparatus 1 (see FIG. 1), and has a front side member (not shown) on the front side and a rear side member (not shown) on the rear side.

[0020] An opening 333 is provided in the housing 332 at a location facing the photoconductor drum 31 (see FIG. 1). A developing roll 334 that adheres a developer to the surface of the photoconductor drum 31 is provided in this opening 333. The developing roll 334 holds the developer to be supplied to the photoconductor drum 31. The position where the developer from the developing roll 334 is supplied to the photoconductor drum 31 is sometimes referred to as the developing position. The developing roll 334, which is an example of a developer holder, is formed in a cylindrical shape and is arranged so as to extend along a direction from the front side to the rear side of the image forming apparatus 1. In addition, the developing roll 334 is arranged so as to extend along the longitudinal direction of the developing unit 33.

[0021] The developing roll 334 is provided with a developing sleeve 334A that is formed of a cylindrical body and that is driven to rotate, and a magnet roll 334B that is disposed inside the developing sleeve 334A. The developing sleeve 334A is made of a metal such as SUS, etc. The developing sleeve 334A rotates in the direction of the arrow D in the figure.

[0022] Furthermore, in this embodiment, at the primary transfer portion T1 (see FIG. 1) between the developing roll 334 and the photosensitive drum 31, the developing sleeve 334A and the photosensitive drum 31 rotate so that they move in the same direction. The developing unit 33 is provided with a layer regulating member 335 that regulates the layer thickness of the developer held on the developing roll 334 .

[0023] 2, the developing device 33 is provided with a first conveying section 336, a second conveying section 337, and a third conveying section 338 that convey the developer. Hereinafter, the first conveying section 336, the second conveying section 337, and the third conveying section 338 may be referred to as conveying sections 336-338.

[0024] The transport sections 336 to 338 are provided on the opposite side of the developing roll 334 to the side on which the photosensitive drum 31 (see FIG. 1) is installed. Each of the transport sections 336 to 338 includes a rotating member 51, 52, 53 extending along the rotation axis of the developing sleeve 334A that is driven to rotate, and rotates around the rotating member 51, 51, 53. That is, the transport sections 336 to 338 are disposed approximately parallel to the photosensitive drum 31 (see FIG. 1).

[0025] The first transport section 336 and the second transport section 337 are different in height, i.e., in their positions in the up-down direction. That is, the developer from the first transport section 336 is transported to the second transport section 337, which is located above the first transport section 336. This is configured as a so-called vertical transport path. In addition, although the developing device 33 according to the present embodiment includes the vertical transport path described above, a configuration that does not include the vertical transport path is also considered. Also, as the vertical transport path, a case where the second transport section 337 is located above the first transport section 336 is shown, but a case where the second transport section 337 is located below the first transport section 336 is also considered.

[0026] 3, the rotating member 51 of the first transport section 336 is provided with a spiral blade portion 51a in the axial direction. When the rotating member 51 rotates, the developer is stirred and transported by the blade portion 51a. The rotating member 52 of the second transport section 337 has a spiral blade portion 52a in the axial direction, and agitates and transports the developer by rotation. The rotating member 53 of the third transport section 338 has a spiral blade portion 53a in the axial direction, and agitates and transports the developer by rotation.

[0027] The developer in the container 331 is supplied to the developing roll 334 via a transport path in which the developer is transported through a first transport section 336, a second transport section 337, and a third transport section 338 in this order. The supply to the developing roll 334 is achieved by moving in a transport direction 50a (leftward in the figure) in the first transport section 336. The supply to the developing roll 334 is achieved by moving in a transport direction 50c (leftward in the figure) in the second transport section 337. The supply to the developing roll 334 is further achieved by moving in a transport direction 50f (rightward in the figure) in the third transport section 338. The conveying directions 50a and 50c are the same direction, and the conveying direction 50f is the opposite direction to the conveying directions 50a and 50c. The conveying direction 50a is an example of a direction in which the sheet is conveyed by another rotating member, and the conveying direction 50c is an example of a direction in which the sheet is conveyed by a rotating member.

[0028] The second conveying section 337 is connected to the first conveying section 336 by an inlet 54 provided downstream in the conveying direction of the blade section 51a of the first conveying section 336 (the left end side in the figure). In addition, the second conveying section 337 is connected to the first conveying section 336 by an outlet 55 provided downstream in the conveying direction of the blade section 52a of the second conveying section 337. The inlet 54 is a connection portion that connects the first transport section 336 and the second transport section 337 to each other, and the outlet 55 is a connection portion that connects the second transport section 337 and the third transport section 338 to each other. In this manner, a transport path for the developer to the developing roll 334 is formed.

[0029] The developer in the first conveying portion 336 advances in an inflow direction 50b at an inlet 54 and flows into the second conveying portion 337. The developer in the second conveying portion 337 advances in an outflow direction 50e at an outlet 55 and flows out to the third conveying portion 338.

[0030] More specifically, the rotating member 52 of the second transport section 337 has a blade portion 52a for transporting the developer in the transport direction 50c described above, i.e., from the inlet 54 to the outlet 55. The rotating member 52 also has a blade portion 52b for transporting the developer in a transport direction 50d, which is the opposite direction to the transport direction 50c, i.e., in the direction away from the outlet 55. The transport direction 50c can be referred to as the main direction, and the transport direction 50d as the sub-direction. The transport direction 50d is an example of the direction opposite to the outlet. Thus, the rotating member 52 includes the blade portion 52a that conveys the material toward the outlet 55 and the blade portion 52b that conveys the material in the direction opposite to the outlet 55.

[0031] As described above, in the second transport section 337, the rotating member 52 is configured so that the transport direction branches into two directions. The second conveying section 337 is an example of a conveying means, the rotating member 52 is an example of a rotating member, and the rotating member 51 is an example of another rotating member. Moreover, the blade portion 52a is an example of a first blade portion, and the blade portion 52b is an example of a second blade portion.

[0032] Here, an inflow developer, which is the developer flowing into the second transport section 337 from the inflow port 54, and an outflow developer, which is the developer flowing out to the third transport section 338 from the outflow port 55, will be described. In the present embodiment, the amount of inflowing developer and the amount of outflowing developer are not the same in the second conveying section 337, but are greater than the amount of outflowing developer. That is, a greater amount of inflowing developer flows in from the inflow port 54 than the outflowing developer flowing out from the outflow port 55. To explain further, the outflowing developer in the second transport section 337 is transported in a transport direction 50c by the blade portion 52a of the rotating member 52, and the remaining developer, obtained by subtracting the amount of outflowing developer from the amount of inflowing developer, is transported in a transport direction 50d by the blade portion 52b of the rotating member 52.

[0033] In this embodiment, the conveying direction 50a by the blade portion 51a of the first conveying section 336 and the conveying direction 50c by the blade portion 52a of the second conveying section 337 are the same direction, but this is not limited to this, and the conveying direction 50a and the conveying direction 50c may be different directions from each other. In addition, when the conveying directions 50a and 50c are the same as in this embodiment, the developer conveyed by the blade portion 51a in the second conveying section 337 is conveyed in the conveying direction 50c by utilizing the inertial force when being conveyed in the conveying direction 50a, so that the developer can be stably discharged from the outlet 55 to the third conveying section 338.

[0034] Here, the relationship between a conveying force F1 when the developer is conveyed by the blade portion 51a of the first conveying portion 336 and a conveying force F2 when the developer is conveyed by the blade portion 52a of the second conveying portion 337 will be described with reference to FIG. FIG. 4 is a diagram illustrating the relationship between the conveying force F1 by the blade portion 51a and the conveying force F2 by the blade portion 52a.

[0035] 4, the developer in the first transport section 336 is transported to the inlet 54 by the transport force F1 of the blade portion 51a. In the second transport section 337, the developer is transported to the outlet 55 by the transport force F2 of the blade portion 52a. In this case, the transport force F1 is higher than the transport force F2 (F1>F2). This difference in transport forces, combined with the branching of the transport direction in the second transport section 337 described above, enables a stable supply of developer to the developing roll 334. If the conveying force F1 is lower than the conveying force F2 or if the conveying forces F1 and F2 are the same, the amount of developer flowing out from the outlet 55 to the third conveying section 338 will gradually decrease, making it difficult to achieve the stable supply described above.

[0036] The conveying force F1 is determined by at least one of the pitch P1, radius R1, and rotation speed K1 of the blade portion 51a, and the conveying force F2 is determined by at least one of the pitch P2, radius R2, and rotation speed K2 of the blade portion 52a.

[0037] For example, when the rotational speeds of the blades 51a and 52a during transport are the same (K1=K2), the size of the pitch P1 and the radius R1 of the blade 51a are configured to be larger than the size of the pitch P2 and the radius R2 of the blade 52a (P1>P2, R1>R2). When the rotational speeds and pitches P1 and P2 of the blades 51a and 52a during transport are the same (K1=K2, P1=P2), the radius R1 of the blade 51a is configured to be larger than the radius R2 of the blade 52a (R1>R2). When the size and radius R1 of the pitch P1 of the blade 51a and the size and radius R2 of the pitch P2 of the blade 52a are the same (P1=P2, R1=R2), the rotational speed K1 of the blade 51a during transport is made higher than the rotational speed K2 of the blade 52a (K1>K2).

[0038] In this embodiment, the blade portion 52a and the blade portion 52b are provided on one rotating member 52, but the present invention is not limited to this. Although not shown in the drawings, for example, the blade portion 52a may be provided on the rotating member 52, and the blade portion 52b may be provided on a rotating member other than the rotating member 52. In such a case, it becomes possible to set the rotation speed of the blade portion 52a and the rotation speed of the blade portion 52b to different values. In such a case, it is preferable that the rotating member 52 and the other rotating member are provided coaxially.

[0039] Here, the position of the blade portion 52a relative to the inlet 54 will be described with reference to FIG. FIG. 5 is a diagram for explaining the position of the blade portion 52a relative to the inlet 54, where (a) shows one example and (b) shows another example. 5(a) and (b), end 52c of blade portion 52a is located within the opening range of inlet 54. That is, end 52c is located in region 54b corresponding to width 54a of inlet 54.

[0040] By adopting such a configuration, the amount of developer transported to the outlet 55 is prevented from becoming excessive or insufficient, compared to when the end 52c is not located in the region 54b. That is, the amount of developer transported to the outlet 55 is increased, compared to when the end 52c is located closer to the outlet 55 side than the region 54b. Also, compared to when the end 52c is located on the opposite side to the outlet 55 side than the region 54b, the amount of developer transported to the outlet 55 is prevented from becoming excessive.

[0041] The region 54b referred to here is a region of the rotating member 52 corresponding to the width 54a of the inlet 54. Moreover, the end 52c referred to here is an end, of both ends in the axial direction of the blade portion 52a, that is farther from the outlet 55. The end 52c is an example of an end of the first blade portion that is farther from the outlet.

[0042] Moreover, when region 54b is divided in two by center line CL of inlet 54 in the width direction W, the side closer to outlet 55 is region 54c, and the side farther from outlet 55 is region 54d. Center line CL is an example of the center in the width direction.

[0043] In the example shown in Fig. 5(a), end 52c of blade portion 52a is located in region 54d. That is, end 52c far from outlet 55 is located on the side far from outlet 55. This increases the amount of developer transported to outlet 55. This is a particularly useful configuration in the case of the vertical transport path described above (see Fig. 2).

[0044] 5(b), the end 52c is located in the region 54c. That is, the end 52c farther from the outlet 55 is located closer to the outlet 55. This prevents the amount of developer transported to the outlet 55 from becoming excessive.

[0045] In this manner, in the present embodiment, a configuration is adopted in which the flow rate of the inflowing developer from the inlet 54 (see, for example, FIG. 3) is made greater than the flow rate of the outflowing developer from the outlet 55 (see the same figure). The second conveying section 337 is provided with a vane portion 52a for conveying the developer in a conveying direction 50c, which is a direction for conveying the inflowing developer toward the outlet 55, and a vane portion 52b for conveying the developer in a conveying direction 50d, which is a direction opposite to the conveying direction 50c (see FIG. 3). Furthermore, the vane portion 52a is disposed at a position that spans the width of the inlet 54. This ensures a stable supply of the developer to the developing roll 334.

[0046] Next, a first embodiment and a second embodiment to which this embodiment is applied will be described with reference to Figures 6 and 7. In Figures 6 and 7, the same reference numerals are used for the members described in this embodiment, and the description thereof may be omitted.

[0047] <First embodiment> FIG. 6 is a diagram illustrating the developing unit 33 according to the first embodiment. In the developing device 33 according to the first embodiment shown in Fig. 6, the developer flowing from the first transport section 336 to the second transport section 337 at the inlet 54 is divided into two directions as shown in the transport direction 50g. A part of the divided developer flows out from the outlet 55 to the third transport section 338. The remaining developer is returned from the second transport section 337 to the upstream side of the first transport section 336 at the return port 56. Note that, as shown in the transport direction 50g, the amount of developer flowing out from the outlet 55 is greater than the remaining developer.

[0048] That is, as described above, when comparing the amount of inflowing developer and the amount of outflowing developer in the second conveying section 337, the amounts are not the same but different, and more specifically, the amount of inflowing developer is greater than the outflowing developer. The difference is returned to the first conveying section 336. This stabilizes the amount of developer supplied from the outlet 55 to the third conveying section 338.

[0049] Furthermore, the developer that has been transported to the third transport section 338 and has not been supplied to the developing roll 334 is returned to the first transport section 336 from a return port 57 located at the downstream end in the transport direction 50f. This allows the developer to be stably supplied from the third transport section 338 to the developing roll 334.

[0050] To explain further, the first embodiment is provided with a detection unit 60 located downstream of the second conveying section 337 for detecting the amount of developer, and a shutter section (not shown) whose opening and closing is controlled based on the detection result of the detection unit 60. When the detection result of the detection unit 60 indicates that the amount of developer does not exceed a predetermined value, a shutter (not shown) is closed, and when the amount of developer exceeds the predetermined value, the shutter (not shown) is opened and the developer is returned from the return port 57 to the third conveying unit 338.

[0051] <Second embodiment> 7 is a diagram illustrating a developing unit 33 according to the second embodiment. Note that a description of parts common to the first embodiment may be omitted. 7, the developer in the second transport section 337 that does not flow out from the outlet 55 to the third transport section 338 is discharged from the outlet 50j located at the downstream end to the outside of the device. This makes it possible to prevent an excessive amount of developer.

[0052] Meanwhile, new developer is supplied from the supply port 50k to the first conveying portion 336. By supplying new developer from the supply port 50k, an increase or decrease in the amount of developer in the developing device 33 is suppressed, and image density is stabilized. In the second embodiment, the above-mentioned detection unit 60 and shutter (not shown) provided in the first embodiment may be provided.

[0053] <Additional Notes> (((1))) a developer carrier for holding a developer containing a toner and a carrier and supplied to an image carrier for forming an electrostatic latent image; a transport means for stirring and transporting the developer flowing in from an inlet by a rotating member, and discharging the developer toward the developer holder from an outlet, the transport means including, as a part constituting the rotating member, a first blade portion for transporting the developer to the outlet and a second blade portion for transporting the developer in a direction opposite to the outlet, and a larger amount of developer flows in from the inlet than flows out from the outlet; A developing device comprising: (((2))) The end of the first blade portion far from the outlet is located in an area corresponding to the width of the inlet. The developing device according to (((1))) above. (((3))) The far end is located on the far side from the outlet when the region is divided in half at the center of the width direction at the inlet, The developing device according to (((2))) above. (((4))) The far end is located on the side closer to the outlet when the region is divided in half at the center of the width direction at the inlet. The developing device according to (((2))) above. (((5))) the developer flowing into the inlet is transported by a transport path formed by a rotating member different from the rotating member of the transport means, The direction of conveyance by the another rotating member is the same as the direction of conveyance by the rotating member. 3. The developing device according to claim 1, wherein the developing device is a developing unit having a first surface and a second surface. (((6))) the developer flowing into the inlet is transported by a transport path formed by a rotating member different from the rotating member of the transport means, The conveying force of the other rotating member is higher than that of the first blade portion. 3. The developing device according to claim 1, wherein the developing device is a developing unit having a first surface and a second surface. (((7))) The magnitude of the conveying force is determined by at least one of the pitch of the blade, the radius of the blade, and the rotation speed during conveyance. The developing device according to (((6))) above. (((8))) The developer transported by the second blade portion can be discharged. The developing device according to ((5))) or ((6))) above. (((9))) an image carrier for forming an electrostatic latent image; a developing means for developing the electrostatic latent image formed on the image carrier into a toner image; a transfer means for transferring the toner image produced by the developing means onto a recording material; a fixing unit for fixing the toner image transferred onto the recording material onto the recording material; Including, The developing means is a developer carrier for holding a developer containing a toner and a carrier and supplied to an image carrier for forming an electrostatic latent image; a transport means for stirring and transporting the developer flowing in from an inlet by a rotating member, and discharging the developer toward the developer holder from an outlet, the transport means including, as a part constituting the rotating member, a first blade portion for transporting the developer to the outlet and a second blade portion for transporting the developer in a direction opposite to the outlet, and a larger amount of developer flows in from the inlet than flows out from the outlet; An image forming apparatus comprising:

[0054] According to the invention of (((1))), compared to a case where the amount of developer is increased by control when the consumption of developer containing toner and carrier increases, it is possible to stably supply developer to the developer holder with a simple configuration even when the consumption of developer increases. According to the invention (((2))), the end of the first blade portion farthest from the outlet can prevent excess or deficiency of developer being transported to the outlet, compared to a case in which the end is not provided with a configuration in which the end is located in an area corresponding to the width of the inlet. According to the invention (((3))), the far end can increase the amount of developer transported to the outlet compared to a case in which the far end is not provided with a configuration located on the far side from the outlet when the area is divided in half at the center of the width at the inlet. According to the invention (((4))), the amount of developer transported to the outlet can be prevented from becoming excessive, compared to a case in which the far end is not provided with a configuration in which it is located on the side closer to the outlet when the area is divided in half at the center of the width at the inlet. According to the invention (((5))), the direction in which the material is transported by another rotating member can utilize inertia force for transport by the rotating member, compared to a case in which the direction in which the material is transported by the rotating member is not the same as the direction in which the material is transported by the rotating member. According to the invention (((6))), the transport force exerted by the separate rotating member is higher than that of the first blade portion, thereby enabling a more stable supply of developer to the developer holder compared to a case in which the configuration is not provided. According to the invention (((7))), the design conditions of the developing unit can be relaxed. According to the invention (((8))), it is possible to prevent the amount of developer from becoming excessive. According to the invention of (((9))), it is possible to stably supply developer to the developer holder with a simple configuration even when the consumption of developer including toner and carrier increases, compared to a case where the amount of developer is increased by control when the consumption of developer increases. [Explanation of symbols]

[0055] 1...image forming apparatus, 31...photosensitive drum, 33...developing unit, 41...intermediate transfer belt, 50a, 50c, 50d...conveying direction, 51, 52...rotating member, 52a, 52b...blade portion, 52c...end portion, 54...inlet, 54a...width, 54b, 54c, 54d...area, 55...outlet, 80...fixing unit, 334...developing roll, 337...second conveying unit, CL...center line, W...width direction

Claims

1. a developer carrier for holding a developer containing a toner and a carrier and supplied to an image carrier for forming an electrostatic latent image; a conveying means for stirring and conveying the developer flowing in from an inlet by a rotating member, and discharging the developer toward the developer holder at an outlet, the conveying means including, as a part constituting the rotating member, a first blade portion for conveying the developer to the outlet and a second blade portion for conveying the developer in a direction opposite to the outlet, and a larger amount of developer flows in from the inlet than flows out from the outlet; A developing device comprising:

2. The end of the first blade portion far from the outlet is located in an area corresponding to the width of the inlet.

2. The developing device according to claim 1,

3. The far end is located on the far side from the outlet when the region is divided in half at the center of the width direction at the inlet, 3. The developing device according to claim 2.

4. The far end is located on the side closer to the outlet when the region is divided in half at the center of the width direction at the inlet.

3. The developing device according to claim 2.

5. the developer flowing into the inlet is transported by a transport path formed by a rotating member different from the rotating member of the transport means, The direction of conveyance by the another rotating member is the same as the direction of conveyance by the rotating member.

2. The developing device according to claim 1,

6. the developer flowing into the inlet is transported by a transport path formed by a rotating member different from the rotating member of the transport means, The conveying force of the other rotating member is higher than that of the first blade portion.

2. The developing device according to claim 1,

7. The magnitude of the conveying force is determined by at least one of the pitch of the blade, the radius of the blade, and the rotation speed during conveyance.

7. The developing device according to claim 6.

8. The developer transported by the second blade portion can be discharged.

7. The developing device according to claim 5 or 6.

9. an image carrier for forming an electrostatic latent image; a developing means for developing the electrostatic latent image formed on the image carrier into a toner image; a transfer means for transferring the toner image produced by the developing means onto a recording material; a fixing unit for fixing the toner image transferred onto the recording material onto the recording material; Including, The developing means is a developer carrier for holding a developer containing a toner and a carrier and supplied to an image carrier for forming an electrostatic latent image; a conveying means for stirring and conveying the developer flowing in from an inlet by a rotating member, and discharging the developer toward the developer holder from an outlet, the conveying means including, as a part constituting the rotating member, a first blade portion for conveying the developer to the outlet and a second blade portion for conveying the developer in a direction opposite to the outlet, and a larger amount of developer flows in from the inlet than flows out from the outlet; An image forming apparatus comprising:

Images