Development device and image forming device

Abstract

To suppress fluctuation of a developer amount to be discharged.SOLUTION: A development device includes: a developer holding body for holding a developer; a storage part for storing the developer supplied to the developer holding body; a rotation shaft rotatably provided inside the storage part; a first conveyance part provided at the rotation shaft, and for conveying the developer in the direction crossing the axis direction of the rotation shaft; a second conveyance part provided at the rotation shaft, and for conveying the developer in the axis direction; a discharge port provided in the storage part, and for discharging part of the developer to the outside at a position corresponding to the position where the first conveyance part is provided in the axis direction; and a pressure adjustment port provided in the storage part, and for adjusting a pressure of the storage part at a position corresponding to the position where the first conveyance part is provided in the rotation direction of the first conveyance part at the discharge port and in the axis direction.SELECTED DRAWING: Figure 7

Description

[Technical field]

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

[0002] Patent Document 1 discloses a developing machine having a discharge section that is arranged downstream of the stirring chamber in a first direction and downstream of the return blade in the first direction and discharges a portion of the developer from the developing device, a first path that connects a portion of the stirring chamber above the return blade with the discharge section and discharges the developer to the discharge section, and a second path that is separated from the first path by a partition wall and connects a portion of the stirring chamber above the developer surface contained in the stirring chamber with the discharge section and allows air to flow from the stirring chamber to the discharge section. Patent document 2 discloses that the developer in the developing chamber is transported in one direction as the first transport screw rotates, and that when toner and carrier are replenished from a hopper to the developing chamber, some of the circulating developer overflows and is discharged from the developer discharge outlet, and that the first transport screw is formed with a spiral blade except for the area along the developer discharge outlet of the developing chamber, and that in that area, ribs are locally formed that stir or vibrate the developer in the area along the developer discharge outlet as the first transport screw rotates. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-96400 [Patent Document 2] JP 2012-234153 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an image forming apparatus using an electrophotographic method or the like, an electrostatic latent image formed on an image carrier is developed into a toner image by a developing device. In such a developing device, in order to suppress deterioration of the developer, a so-called trickle mechanism is used in which excess developer is discharged from an outlet and new developer is replenished to gradually replace the developer. When the trickle mechanism is employed and the developer is discharged from the outlet, if pressure fluctuations occur at the outlet, the amount of developer discharged will fluctuate. An object of the present invention is to suppress fluctuations in the amount of developer discharged. [Means for solving the problem]

[0005] The invention described in claim 1 is a developing device comprising: a developer holder that holds developer; a storage section that stores developer supplied to the developer holder; a rotating shaft rotatably arranged inside the storage section; a first transport section arranged on the rotating shaft that transports the developer in a direction intersecting the axial direction of the rotating shaft; a second transport section arranged on the rotating shaft that transports the developer in the axial direction; an outlet arranged in the storage section that discharges a portion of the developer to the outside at a position corresponding to the position at which the first transport section is arranged in the axial direction; and a pressure adjustment port arranged in the storage section that adjusts the pressure in the storage section at a position of the outlet in the rotational direction of the first transport section and corresponding to the position at which the first transport section is arranged in the axial direction. The invention described in claim 2 is the developing device described in claim 1, characterized in that the first transport portion has a transport surface portion which is a surface that transports the developer in the intersecting direction as the rotation shaft rotates, the discharge outlet is provided at a position where at least a portion of the axial direction overlaps with the transport surface portion, and the pressure adjustment port is provided at a position where at least a portion of the axial direction overlaps with the transport surface portion. The invention described in claim 3 is the developing device described in claim 1, characterized in that at least a portion of the discharge port and the pressure adjustment port in the axial direction overlap with each other in the rotation direction of the first transport part. The invention described in claim 4 is the developing device described in claim 1, characterized in that the second transport section includes an agitating and transporting section that transports the developer in one direction while agitating it, and a turning section that is provided at the axial end of the rotating shaft and transports the developer transported in one direction by the agitating and transporting section in a direction opposite to the one direction, and the first transport section is provided at a position in the axial direction where the turning section is located. The invention described in claim 5 is the developing device described in claim 1, characterized in that the second transport portion is a blade spirally arranged on the rotating shaft, and the first transport portion is arranged between the spiral blades. The invention described in claim 6 is the developing device described in claim 5, characterized in that the first transport portion is disposed between the blades and biased toward the surface side of the blade that transports the developer. According to a seventh aspect of the present invention, there is provided the developing device according to the sixth aspect, wherein a gap is provided between the blade and the first transport portion. An eighth aspect of the present invention is the developing device according to the sixth aspect, wherein a tip of the first transport portion is positioned closer to the center of the rotation shaft than a tip of the blade. The invention described in claim 9 is a developing device as described in claim 1, characterized in that the opening of the discharge port and the opening of the pressure adjustment port are formed by a common opening which is a single opening provided in the storage section and a blocking section which blocks a portion of the common opening. The invention described in claim 10 is the developing device described in claim 9, characterized in that the blocking portion has different positions and / or shapes of the discharge outlet and the pressure adjustment outlet depending on the characteristics of the developer contained in the container. An eleventh aspect of the present invention provides the developing device according to the ninth aspect, wherein the closing portion has a slope that moves the developer that has entered the opening of the pressure adjusting port toward the container portion. The invention described in claim 12 is an image forming apparatus that includes a developing device described in any one of claims 1 to 11, and forms an image on a recording material by developing an electrostatic latent image formed by a photosensitive member with a developer whose charge has been stabilized by the developing device. Effect of the Invention

[0006] According to the first aspect of the present invention, the fluctuation in the amount of developer discharged is suppressed. According to the invention of claim 2, the developer amount can be stably discharged compared to a case where the transport surface portion is not provided, thereby suppressing fluctuations in the developer amount. According to the invention of claim 3, the air flow is improved and pressure regulation is improved compared to a case where the exhaust port and the pressure adjustment port do not partially overlap. According to the invention of claim 4, when the amount of developer in the container increases, the developer is quickly discharged. According to the invention of claim 5, the developer can be discharged by utilizing a mechanism for transporting the developer by means of a blade. According to the invention of claim 6, the amount of developer discharged is increased compared to a case where the first transport portion is provided away from the surface where the blade transports the developer. According to the seventh aspect of the invention, the fluctuation in the amount of developer discharged is suppressed, compared to a case where there is no gap between the blade and the first transport portion. According to the invention of claim 8, discharge of developer from the pressure adjustment port is suppressed, compared to a case in which the tip of the first conveying portion extends beyond the tip of the blade. According to the invention of claim 9, the shape of the discharge port and the shape of the pressure adjustment port can be easily changed. According to the tenth aspect of the present invention, the fluctuation in the amount of developer discharged is suppressed depending on the type of developer. According to the invention of claim 11, the flow of air from the pressure adjusting port is permitted while the discharge of developer is suppressed. According to the twelfth aspect of the present invention, the quality of the image formed on the recording material is improved. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an image forming apparatus. [Diagram 2] FIG. [Diagram 3] FIG. 3 is a diagram for explaining the inside of the storage unit, showing the internal structure of the storage unit from the upper side in the up-down direction of FIG. 2. [Figure 4] 4 is a perspective view showing a front end side of a housing portion extending in the axial direction. FIG. [Diagram 5] FIG. 5 is a perspective view of FIG. 4 with a blocking portion removed. [Figure 6] FIG. 5 is a detailed view of the blocking portion shown in FIG. 4. [Figure 7] 7 is a schematic diagram of the inside of the mixing passage as viewed from the VII direction in FIG. 4, illustrating the positional relationship between the discharge paddle, the discharge port, and the pressure adjustment port in the axial direction. FIG. [Figure 8] 8 is a diagram showing a part of a cross section taken along line VIII-VIII in FIG. 3, illustrating the positional relationship among a discharge paddle, a discharge port, and a pressure adjustment port in a direction intersecting the axial direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. [Description of Image Forming Apparatus] 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 is a developing device 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.

[0011] The image forming section 20 is also provided with an 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 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 to 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.

[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 exposure device 26. Then, for example, in a magenta (M) image forming unit 30M, after the surface of the photosensitive drum 31 is charged by the charging roll 32, the 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] [Description of the developing device] Next, a description will be given of the developing device, that is, the developing unit 33. Since the developing units 33 for each color have the same structure, the following description will be given by taking one developing unit 33 as an example. FIG. 2 is a diagram illustrating the developing unit 33. As shown in FIG. The developing device 33 includes a developing roll 51 that develops the electrostatic latent image on the photoconductor drum 31, a pumping roll 52 that supplies developer to the developing roll 51, and a container 53 that contains the developer pumped up by the pumping roll 52. The developing device 33 also includes a toner bottle 57 that supplies toner to the container 53, and a discharge path 58 that serves as a path for disposing of the developer discharged from the container 53. The developing roll 51 functions as a developer holder that holds the developer.

[0020] The developing roll 51 rotates while holding the developer, and develops the electrostatic latent image on the photoconductor drum 31. The pumping roll 52 is located above a supply path 56 (described later) in the vertical direction. Here, the vertical direction refers to the direction of gravity as the downward direction, and the opposite direction to the direction of gravity as the upward direction. The pumping roll 52 pumps up the developer in the supply path 56 arranged along the pumping roll 52, and supplies the developer to the developing roll 51.

[0021] The storage section 53 stores the developer and transports the developer while stirring it. The storage section 53 includes a supply path 54, a stirring path 55, and a supply path 56 as paths for transporting the developer. In FIG. 2, the supply path 54, the stirring path 55, and the supply path 56 are pipe paths that extend in the axial direction of the developing roll 51 in a direction perpendicular to the paper surface, toward the front side and the back side of the device. The supply path 54 includes a supply auger 540 that transports the developer in the supply path 54. The stirring path 55 includes a stirring auger 550 that transports the developer in the stirring path 55, and includes an outlet 68 for discharging a portion of the developer to the outside, and a pressure adjustment port 69 for adjusting the pressure in the stirring path 55. The outlet 68 and the pressure adjustment port 69 are openings opened on the side of the stirring path 55, and the lower end of the opening of the pressure adjustment port 69 is provided above the upper end of the opening of the outlet 68. A connection portion 63 for connecting to the discharge path 58 protrudes horizontally from the outer periphery of the agitation path 55. The supply path 56 is provided with a supply auger 560 for transporting the developer in the supply path 56.

[0022] The toner bottle 57 is connected to a developer supply port 61 (see FIG. 3) provided on the front side of the supply path 54 in the drawing, and new toner in the toner bottle 57 is supplied to the supply path 54. The discharge path 58 is configured to cover both the openings of the discharge port 68 and the pressure adjustment port 69, so as to prevent the developer discharged from the discharge port 68 from leaking into the image forming apparatus 1. The discharge path 58 is connected to a recovery bottle for recovering used developer, and the discharged developer is recovered therein. The discharge path 58 is fixed to the connection portion 63 by, for example, a bolt or the like.

[0023] Fig. 3 is a diagram for explaining the inside of storage unit 53, and shows the internal structure of storage unit 53 from the upper side in the vertical direction of Fig. 2. The left side of Fig. 3 is the front side, and the right side is the back side, with replenishing auger 540, mixing auger 550, and supply auger 560 extending in the axial direction.

[0024] Supply path 54 and mixing path 55 are connected by a first communication path 511 that crosses supply path 56 at the rear side of the device, and developer is transported through the first communication path 511. In addition, mixing path 55 and supply path 56 are connected by a second communication path 512 at the front side of the device, and developer is transported through the second communication path 512.

[0025] [Supply route 54] Supply path 54, which is a part of storage section 53, has developer supply port 61, which is an opening for supplying new developer. Developer supply port 61 is connected to toner bottle 57 (see FIG. 2). Supply auger 540 has a rotating shaft 541 rotatably attached within supply path 54. Rotating shaft 541 is rotatably provided from the front side to the back side of supply path 54. A spiral blade 542 for transporting developer, a reverse spiral blade 543, and a push-up paddle 544 are provided on rotating shaft 541 of supply auger 540.

[0026] The spiral blade 542 transports the developer from the front side to the back side in the axial direction as the rotating shaft 541 rotates. This transport direction is shown as direction G1 in Fig. 3. The reverse spiral blade 543 pushes back the developer that has been transported to the back end of the supply path 54 to the front side. The push-up paddle 544 is provided at a position corresponding to the first communication path 511 of the supply path 54, and transports the developer to the supply path 56 via the first communication path 511.

[0027] [Mixing path 55] The mixing path 55, which is a part of the container 53, includes the discharge port 68, the pressure adjustment port 69 (see FIG. 2), and the mixing auger 550 for transporting the developer in the mixing path 55, as described above. The agitating auger 550 includes a rotating shaft 551 that is rotatably provided inside the agitating path 55 from the front side to the back side. The agitating auger 550 also includes a spiral blade 552 for transporting the developer, an inverse spiral blade 553, and a discharge paddle 554. The spiral blade 552, the inverse spiral blade 553, and the discharge paddle 554 are provided on the rotating shaft 551. The spiral blade 552 is an example of an agitation conveying portion, and the reverse spiral blade 553 is an example of a turning portion. The spiral blade 552 and the reverse spiral blade 553 are an example of a second conveying portion. The discharge paddle 554 is an example of a first conveying portion.

[0028] The spiral blade 552 transports the developer from the rear side to the front side in the axial direction as the rotary shaft 551 rotates. This transport direction is shown as a G3 direction in FIG. The reverse spiral blade 553 is provided on the front side of the rotating shaft 551. As the rotating shaft 551 rotates, the reverse spiral blade 553 transports the developer from the front side to the rear side in the axial direction. This transport direction is shown as direction G4 in Figure 3. In other words, the reverse spiral blade 553 transports the developer that has been transported in one direction while being stirred by the spiral blade 552, in the direction opposite to this one direction. The discharge paddle 554 is provided at a position in the axial direction where the reverse spiral blade 553 is disposed, and is provided between the blades of the reverse spiral blade 553. The discharge paddle 554 transports the developer toward the discharge port 68 as the rotating shaft 551 rotates. In other words, the discharge paddle 554 transports the developer in a direction intersecting the axial direction of the rotating shaft 551.

[0029] [Supply route 56] Supply auger 560 of supply path 56, which is a part of storage section 53, includes a rotating shaft 561 that is rotatably attached within supply path 56. Supply auger 560 is provided on rotating shaft 561, and includes a spiral blade 562 for transporting developer, a reverse spiral blade 563, a damming spiral blade 564, and a transfer plate 565. The spiral blade 562, the reverse spiral blade 563, the damming spiral blade 564, and the transfer plate 565 are provided on the rotating shaft 561.

[0030] The spiral blade 562 transports the developer from the front side to the back side in the axial direction as the rotating shaft 561 rotates. This transport direction is shown as direction G2 in Fig. 3. The reverse spiral blade 563 pushes back the developer transported to the end of the back side of the supply path 56 to the front side as the rotating shaft 561 rotates. The damming spiral blade 564 dams up the developer transported from the front side to the back side by the spiral blade 562 as the rotating shaft 561 rotates, and encourages the developer to flow into the mixing path 55. The delivery plate 565 is provided at a position corresponding to the first communication path 511, and transports the developer to the mixing path 55 as the rotary shaft 561 rotates.

[0031] [Explanation of the exhaust port 68 and the pressure adjustment port 69] Next, the exhaust port 68 and the pressure adjustment port 69 to which this embodiment is applied will be described with reference to FIGS. 4 is a perspective view showing the front end side of the axially extending housing portion 53. Here, the through hole 64 and the blocking portion 65 of the connection portion 63 are shown. FIG. 5 is a perspective view of FIG. 4 with the blocking portion 65 removed. FIG. 6 is a detailed view of the blocking portion 65 shown in FIG.

[0032] As shown in Fig. 4, a connection part 63 for connecting to the discharge path 58 (see Fig. 2) is provided on the axial front side of the mixing path 55. This connection part 63 is provided to protrude from the outer surface of the mixing path 55, and has a thickness from the outer surface of the mixing path 55 toward the outside in the discharge direction. The connection part 63 has a through hole 64 that connects the mixing path 55 and the discharge path 58. The connection part 63 also has a blocking part 65 that blocks a part of the through hole 64. The through hole 64 and the blocking part 65 form a discharge port 68 and a pressure adjustment port 69.

[0033] 5, the through hole 64 has an inner side opening 641 which is an opening on the mixing path 55 side, and an outer side opening 642 which is an opening on the discharge path 58 side. The inner side opening 641 is an example of a common opening which is an opening provided in the mixing path 55 which constitutes a part of the storage section 53. The inner side opening 641 and the outer side opening 642 have a rectangular shape when viewed from the outside to the inside in the discharge direction in FIG.

[0034] The through hole 64 has, for example, four inner surfaces. A lower inner surface 643, which is the lower inner surface of the four inner surfaces, is formed as a slope that extends downward as it advances to the outside so that the through hole 64 widens from the inside to the outside of the mixing passage 55. An upper inner surface 644, which is the upper inner surface of the four inner surfaces, is a surface parallel to the horizontal plane. A first inner side surface 645 on the axial front side and a second inner side surface 646 on the axial rear side are disposed facing each other.

[0035] Next, blocking portion 65 (see FIG. 4) is formed so as to block a part of the inside of through hole 64. This blocking portion 65 is provided so as to be replaceable. Then, blocking portion 65 makes it possible to change the position or shape, or the position and shape, of discharge port 68 and pressure adjustment port 69 provided in connection portion 63 according to the characteristics of the developer contained in container 53.

[0036] In the example shown in FIG. 6, the blocking portion 65 has a lower surface 652 provided so as to follow the slope of the lower inner surface 643 of the through hole 64. The width of the blocking portion 65 is made to be approximately the same as the width of the through hole 64. The height of the blocking portion 65 is shorter than the height of the external opening 642 of the through hole 64, and when the lower surface 652 is brought into contact with the lower inner surface 643, a gap is formed at the upper part of the through hole 64 as shown in FIG. 4. This gap is the pressure adjustment port 69. This gap allows the air in the mixing path 55 to be discharged to the outside of the mixing path 55, and the pressure inside the mixing path 55 is adjusted.

[0037] In addition, when the blocking portion 65 is placed in the through hole 64, the upper surface 651, which is the upper surface of the blocking portion 65, is a slope that extends upward as it proceeds from the inside to the outside of the mixing path 55. For example, the developer may be splashed up by the discharge paddle 554 (see FIG. 3) and may pass through the pressure adjustment port 69 and be positioned on the upper surface 651. In this case, the developer on the upper surface 651 falls along the slope and moves toward the mixing path 55, which is a part of the storage portion 53. In addition, the blocking portion 65 has a recessed portion 658 whose lower right portion is recessed in FIG. 6. When the blocking portion 65 is fitted into the through hole 64, the gap formed by the recessed portion 658 and the through hole 64 becomes the discharge port 68 for discharging the developer.

[0038] [Regarding the relative positions of the exhaust port, pressure adjustment port, and exhaust paddle] Next, the positional relationship between the discharge paddle 554, the discharge port 68, and the pressure adjustment port 69 will be described with reference to Figures 7 and 8. Figure 7 is a schematic diagram of the inside of the stirring path 55 viewed from the VII direction in Figure 4, and is a diagram explaining the positional relationship between the discharge paddle 554, the discharge port 68, and the pressure adjustment port 69 in the axial direction. Also, Figure 8 is a diagram showing a part of the VIII-VIII cross section in Figure 3, and is a diagram explaining the positional relationship between the discharge paddle 554, the discharge port 68, and the pressure adjustment port 69 in the direction intersecting the axial direction.

[0039] As shown in FIGS. 7 and 8, the discharge paddle 554 is a plate-like member provided on the rotary shaft 551, and the shape of the plate surface of the discharge paddle 554 is a rectangular shape. One surface of the discharge paddle 554 is attached so as to face the surface of the rotary shaft 551. Of the front and back plate surfaces of the discharge paddle 554, the surface facing the surface of the rotary shaft 551 is the discharge surface 554a, which functions as a conveyance surface portion for conveying the developer in a direction intersecting the axial direction. This discharge surface 554a is provided so as to extend in the tangential direction of the cross-sectional circle of the rotary shaft 551.

[0040] As shown in FIG. 7, the discharge paddle 554 is provided between the blades of the reverse spiral blade 553 in the axial direction. Here, the direction in which the reverse spiral blade 553 conveys the developer is from the front side to the back side, which is the opposite direction to the direction in which the spiral blade 552 conveys the developer. Therefore, the developer conveyed by the reverse spiral blade 553 adheres to the back side surface of the reverse spiral blade 553. For this reason, the discharge paddle 554 is attached at a position closer to the back side surface of the reverse spiral blade 553, that is, on the front side of the pitch of the reverse spiral blade 553, in order to discharge more developer. More specifically, if the length from the axial center of the discharge paddle 554 to the surface of the reverse spiral blade 553 on the front side in the axial direction is L1, and the length to the surface of the reverse spiral blade 553 on the back side in the axial direction is L2, it is configured such that L1 < L2, and the reverse spiral blade 553, which is the second conveyance portion, is biased toward the surface side for conveying the developer, and the discharge paddle 554, which is the first conveyance portion, is arranged.

[0041] Also, as described above, the discharge paddle 554 is arranged biased toward the front side in the axial direction, but there is a gap between the blade of the reverse spiral blade 553 and the discharge paddle 554. Due to this gap, the developer between the blade of the reverse spiral blade 553 and the discharge surface 554a of the discharge paddle 554 spills from the discharge surface 554a, and fluctuations in the amount of developer placed on the discharge surface 554a are suppressed.

[0042] Furthermore, the length from the center of the rotating shaft 551 to the tip of the discharge paddle 554 is shorter than the length from the center of the rotating shaft 551 to the tip of the reverse spiral blade 553. In other words, the tip of the discharge paddle 554 is located closer to the center of the rotating shaft than the tip of the reverse spiral blade 553. This suppresses the discharge of developer from the pressure adjustment port 69.

[0043] The discharge port 68 is provided at a position in the axial direction corresponding to the position where the discharge paddle 554 is provided. A portion of the position of the discharge port 68 in the axial direction coincides with a portion of the position of the discharge paddle 554 in the axial direction. In other words, the discharge port 68 is provided at a position where at least a portion in the axial direction overlaps with the discharge surface 554a. The discharge surface 554a of the discharge paddle 554 is at a position corresponding to the direction in which the developer is transported. This allows the discharge paddle 554 to promote the discharge of the developer from the discharge port 68.

[0044] The pressure adjustment port 69 is provided at a position in the axial direction corresponding to the position where the discharge paddle 554 is provided. A part of the position of the pressure adjustment port 69 in the axial direction coincides with a part of the position of the discharge paddle 554 in the axial direction. In other words, the pressure adjustment port 69 is provided at a position where at least a part of the axial direction overlaps with the discharge surface 554a. In this way, the pressure fluctuation caused by the rotation of the discharge paddle 554 is suppressed by the pressure adjustment port 69.

[0045] 8, the rotating shaft 551 rotates in a clockwise direction (direction D in the figure). The pressure adjustment port 69 is provided such that at least a part of the axial direction is located above the discharge port 68 and downstream in the direction of rotation. This allows the pressure adjustment port 69 to adjust pressure fluctuations caused by the developer being discharged from the discharge port 68.

[0046] [Effect] Next, the operation of the developing unit 33 to which this embodiment is applied will be described. First, the flow of circulation of the developer contained in the storage section 53 will be described with reference to FIG. 3. New developer supplied from the developer supply port 61 is transported from the front side to the back side in the supply path 54. The developer transported to the back side is transported to the mixing path 55 via the first communication path 511. The developer is then transported from the back side to the front side in the mixing path 55, and is transported to the supply path 56 via the second communication path 512. At this time, a part of the developer in the mixing path 55 advances to the back of the reverse spiral blade 553 and is discharged from the discharge port 68 to the outside of the storage section 53. The developer transported to the supply path 56 advances from the front side to the back side in the supply path 56. At this time, a part of the developer is pumped up by the pumping roll 52 (see FIG. 2) provided at the upper part of the supply path 56 and supplied to the developing roll 51. The developer not pumped up by the pumping roll 52 is transported to the back side of the supply path 56. The developer transported to the inner side of the supply path 56 is transported to the agitation path 55 and circulated.

[0047] Next, the flow of the developer discharged from the discharge port 68 will be described with reference to FIGS. 7, a portion of the developer transported from the rear side to the front side in the axial direction by the spiral blade 552 advances to the rear of the reverse spiral blade 553, and is transported from the front side to the rear side by the reverse spiral blade 553. A portion of the developer transported to the position where the discharge paddle 554 is provided is discharged to the discharge port 68 by the discharge surface 554a of the discharge paddle 554. In FIG. 8, the flow of the developer discharged from the discharge port 68 is indicated by an arrow G5.

[0048] Next, the flow of air discharged from the pressure adjustment port 69 will be described with reference to FIG. The discharge paddle 554 has a discharge surface 554a facing a direction intersecting the rotation shaft 551 in order to transport the developer to the discharge port 68, and this discharge surface 554a moves not only the developer but also the air in the mixing path 55 in a direction intersecting the rotation shaft 551. Therefore, the discharge paddle 554 can be a factor of fluctuation in the pressure of the air in the mixing path 55. Here, the pressure adjustment port 69 is provided in the upper part of the discharge port 68 in the direction in which the discharge surface 554a faces, and a part of the air moved by the discharge surface 554a flows into the pressure adjustment port 69. The air flowing into the pressure adjustment port 69 flows out to the discharge path 58, which is outside the mixing path 55, through a through hole formed by the connection portion 63 and the blocking portion 65. In FIG. 8, the flow of air flowing out of the pressure adjustment port 69 is indicated by an arrow K.

[0049] The flow of air from the pressure adjustment port 69 suppresses pressure fluctuations caused by the exhaust paddle 554, which can be a cause of pressure fluctuations. In other words, pressure fluctuations around the exhaust port 68 provided at a position corresponding to the exhaust paddle 554 are suppressed.

[0050] As described above in detail, in this embodiment, the discharge paddle 554 transports the developer to the discharge port 68, thereby suppressing fluctuations in the discharge amount due to the fluidity of the developer, and the provision of the pressure adjustment port 69 suppresses fluctuations in the discharge amount due to pressure fluctuations generated by the discharge paddle 554.

[0051] [Additional Notes] (((1))) A developer carrier for holding a developer; a container for containing a developer to be supplied to the developer carrier; A rotation shaft rotatably provided inside the housing portion; a first transport section provided on the rotating shaft and configured to transport the developer in a direction intersecting an axial direction of the rotating shaft; a second transport portion provided on the rotation shaft and configured to transport the developer in the axial direction; a discharge port provided in the container and configured to discharge a portion of the developer to the outside at a position corresponding to a position in the axial direction where the first transport portion is provided; a pressure adjustment port provided in the storage section and configured to adjust a pressure in the storage section at a position of the discharge port in a rotation direction of the first transport section and in the axial direction corresponding to a position where the first transport section is provided; A developing device comprising: (((2))) the first transport portion includes a transport surface portion that is a surface that transports the developer in the intersecting direction as the rotation shaft rotates, The discharge port is provided at a position where at least a portion in the axial direction overlaps with the transport surface portion, The developing device described in (((1))) is characterized in that the pressure adjustment port is provided at a position where at least a portion of the axial direction overlaps with the transport surface portion. (((3))) The developing device described in (((1))) is characterized in that at least a portion of the discharge port and the pressure adjustment port in the axial direction overlap with each other in the rotation direction of the first transport section. (((4))) the second transport section includes a stirring and transporting section which transports the developer in one direction while stirring the developer, and a turning section which is provided at an end of the rotation shaft in an axial direction and transports the developer transported in the one direction by the stirring and transporting section in a direction opposite to the one direction; The developing device described in any one of ((1))) to (((3))), wherein the first transport portion is provided at a position in the axial direction where the turning portion is disposed. (((5))) The second conveying portion is a blade provided in a spiral shape on the rotating shaft, The developing device described in any one of ((1))) to (((3))) is characterized in that the first transport portion is provided between the spiral blades. (((6))) The developing device described in (((5))) is characterized in that the first transport portion is disposed between the blades and biased toward the surface side of the blade that transports the developer. (((7))) The developing device described in (((6))) has a gap between the blade and the first transport portion. (((8))) The developing device described in any one of ((5))) to ((7))), wherein a tip of the first transport portion is located closer to the center of the rotation shaft than the tip of the blade. (((9))) The developing device described in (((1))) is characterized in that the opening of the discharge port and the opening of the pressure adjustment port are formed by a common opening that is a single opening provided in the storage section and a blocking section that blocks a portion of the common opening. (((10))) The developing device described in (((9))) is characterized in that the blocking portion has different positions and / or shapes of the discharge port and the pressure adjustment port depending on the characteristics of the developer contained in the container. (((11))) The developing device described in (((9))) is characterized in that the closing portion has a slope that moves the developer that has entered the opening of the pressure adjustment port toward the container portion. (((12))) A developing device according to any one of ((1))) to (((11))), An image forming apparatus that forms an image on a recording material by developing an electrostatic latent image formed by a photoconductor with a developer having a stable charge by the developing device.

[0052] According to the developing device (((1))), fluctuations in the amount of developer discharged are suppressed. According to the developing device of (((2))), the developer amount can be stably discharged, compared to a case where the developing device does not have a transport surface portion, thereby suppressing fluctuations in the amount of developer. According to the developing device of (((3))), the air flow is improved and pressure regulation is improved compared to a case where the discharge port and the pressure adjustment port do not partially overlap. According to the developing device of (((4))), when the amount of developer in the container increases, the developer is quickly discharged. According to the developing device of (((5))), the developer can be discharged by utilizing a mechanism for transporting the developer by means of blades. According to the developing device of (((6))), the amount of developer discharged is increased compared to when the first transport portion is provided away from the surface on which the blade transports the developer. According to the developing device of (((7))), the fluctuation in the amount of developer discharged is suppressed compared to when there is no gap between the blade and the first transport portion. According to the developing device of (((8))), it is possible to prevent developer from being discharged from the pressure adjustment port, compared to a case in which the tip of the first transport portion extends beyond the tip of the blade. According to the developing device of (((9))), the shape of the discharge port and the shape of the pressure adjustment port can be easily changed. According to the developing device of (((10))), the variation in the amount of developer discharged is suppressed depending on the type of developer. According to the developing device of (((11))), while allowing air to flow from the pressure adjustment port, the discharge of developer is suppressed. According to the image forming apparatus of (((12))), the quality of the image formed on the recording material is improved. [Explanation of symbols]

[0053] 1...image forming apparatus, 33...developing device, 53...storage section, 54...supply path, 55...mixing path, 56...supply path, 57...toner bottle, 58...discharge path, 61...developer supply port, 63...connection section, 64...through hole, 65...blocking section, 68...discharge port, 69...pressure adjustment port, 550...mixing auger, 551...rotating shaft, 552...spiral blade, 554...discharge paddle, 554a...discharge surface, 641...inner opening, 642...outer opening, 643...lower inner surface, 644...upper inner surface, 651...upper surface, 652...lower surface, 658...recessed portion

Claims

1. A developer carrier for holding a developer; a container for containing a developer to be supplied to the developer carrier; A rotation shaft rotatably provided inside the housing portion; a first transport section provided on the rotation shaft and configured to transport the developer in a direction intersecting an axial direction of the rotation shaft; a second transport portion provided on the rotation shaft and configured to transport the developer in the axial direction; a discharge port provided in the container, the discharge port being arranged to discharge a portion of the developer to the outside at a position corresponding to a position in the axial direction where the first transport portion is provided; a pressure adjustment port provided in the storage section and configured to adjust a pressure in the storage section at a position of the discharge port in a rotation direction of the first transport section and in the axial direction corresponding to a position where the first transport section is provided; A developing device comprising:

2. the first transport portion includes a transport surface portion that is a surface that transports the developer in the intersecting direction as the rotation shaft rotates, The discharge port is provided at a position where at least a portion in the axial direction overlaps with the transport surface portion, The developing device according to claim 1 , wherein the pressure adjustment port is provided at a position where at least a portion of the pressure adjustment port in the axial direction overlaps with the transport surface portion.

3. The developing device according to claim 1 , wherein the discharge port and the pressure adjustment port at least partially overlap in the axial direction in the rotation direction of the first transport section.

4. the second transport section includes a stirring and transporting section which transports the developer in one direction while stirring the developer, and a turning section which is provided at an end of the rotation shaft in an axial direction and transports the developer transported in the one direction by the stirring and transporting section in a direction opposite to the one direction; The developing device according to claim 1 , wherein the first transport portion is provided at a position where the turning portion is disposed in the axial direction.

5. The second conveying portion is a blade provided in a spiral shape on the rotating shaft, 2. The developing device according to claim 1, wherein the first transport portion is provided between the spiral blades.

6. 6. The developing device according to claim 5, wherein the first transport portion is disposed between the blades and biased toward a surface side of the blade that transports the developer.

7. The developing device according to claim 6 , further comprising a gap between the blade and the first transport portion.

8. 7. The developing device according to claim 6, wherein a tip of the first transport portion is located closer to the center of the rotation shaft than a tip of the blade.

9. 2. The developing device according to claim 1, wherein the opening of the discharge port and the opening of the pressure adjustment port are formed by a common opening that is one opening provided in the storage portion and a closing portion that closes a part of the common opening.

10. 10. The developing device according to claim 9, wherein the closing portion has different positions and / or shapes of the discharge port and the pressure adjustment port depending on the characteristics of the developer contained in the container.

11. 10. The developing device according to claim 9, wherein the closing portion has a slope that moves the developer that has entered the opening of the pressure adjusting port toward the container portion.

12. A developing device according to any one of claims 1 to 11, An image forming apparatus that forms an image on a recording material by developing an electrostatic latent image formed by a photoconductor with a developer having a stable charge by the developing device.

Images