JP2009122534A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a developer which has infiltrated from the discharge port of a developing device less apt to mix with the developer stored in the developing device. <P>SOLUTION: The developing device is provided with a first developer storage chamber and a second developer storage chamber which store the developer, and a developing roll. The first developer storage chamber and the second developer storage chamber are communicated with each other through a first opening and a second opening. The second developer storage chamber is provided with the discharge port for discharging surplus developer to the outside of the device. The second developer storage chamber has a discharge area which includes a position, where the discharge port is provided and is for discharging the developer from the discharge port and in a part of the discharge area, the volume between the second developer storage chamber and a second conveying member is smaller than the volume of the area except a part of the discharge area. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

2. Description of the Related Art A two-component development method in which development is performed while stirring and transporting a two-component developer including a toner and a carrier in a developing device has become widespread. In this two-component development system, in order to prevent the developer from being stirred and deteriorated for a long time in the developing device, the excess developer is discharged from the discharge port while supplying a new developer. Technology is known. In Patent Document 1, a developer discharge cylinder for transporting a developer discharged from a discharge port is provided for each color developer, so that different color developers discharged from other developers can be placed in the developer. A technique for preventing intrusion is disclosed.
Japanese Patent Application Laid-Open No. 11-065216

By the way, in the tandem type developing device, in order to efficiently recover the deteriorated developer, the developer of each color discharged from the discharge port of each developing device is transferred to a recovery container through one recovery path. There is something to transport. In this case, a part of the developer discharged from the developing device located on the upstream side of the recovery path deviates from the recovery path and enters the inside from the discharge port of the developing device positioned on the downstream side of the recovery path. Sometimes. Since the developer discharged from other developing devices contains toners of different colors, if the developer that has entered from the discharge port enters the developer contained in the developing device, the developer is developed. Defects will occur in the image. In order to prevent this, for example, as in Patent Document 1 described above, a dedicated path for discharging the developer discharged from the discharge port to the recovery path is provided for each developing device, and the same color in the path dedicated for discharging is provided. A method to prevent only the developer from entering from the discharge port, or a method of providing a valve that automatically opens and closes at the discharge port and closing the discharge port with a valve except for discharging the excess developer is considered. . However, such a method hinders the downsizing of the developing device and increases the manufacturing cost.
The present invention has been made in view of such a background, and an object of the present invention is to make it difficult for the developer that has entered from the outlet of the developing device to be mixed into the developer contained in the developing device. To do.

  In order to solve the above problems, the present invention provides a first developer storage chamber and a second developer storage chamber for storing a developer, the first developer storage chamber, and the second developer storage chamber. The first opening and the second opening that communicate with each other, and the developer that is provided in the first developer accommodating chamber and that is accommodated in the first developer accommodating chamber. A first conveying member that moves to the second developer accommodating chamber through the first opening; and a second conveying chamber that is provided inside the second developer accommodating chamber and accommodated in the second developer accommodating chamber. A second transport member for transporting the developer being transported to the first developer storage chamber through the second opening, and the second opening in the second developer storage chamber. The second developer collection is provided at a position opposite to the side where the first opening is located when viewed from the position of the section. A discharge port for discharging a part of the developer stored in the chamber to the outside of the apparatus, and the developer supplied from the first developer storage chamber or the second developer storage chamber, A developer holding body that performs development by moving the developer to a position facing the image holding body on which the latent image is formed, and the second developer storage chamber is provided with the discharge port. A discharge region for discharging the developer from the discharge port, and in the partial region of the discharge region between the discharge port and the second opening, the second Provided is a developing device in which a volume between a developer storage chamber and the second transport member is smaller than the volume in a region other than the partial region in the discharge region. .

  In a preferred aspect of the present invention, the first developer storage chamber and the second developer are provided at a position opposite to the side where the second opening is present as viewed from the position of the discharge port. A third opening that communicates with the storage chamber; and in a part of the discharge region between the discharge port and the third opening, the second developer storage chamber and the The volume between the second transport member and the second transport member may be smaller than the volume in a region other than the partial region in the discharge region.

  In a preferred aspect of the present invention, the second developer containing chamber has a thickness that fits between an inner wall surface of the second developer storage chamber and an outer edge of the second transport member, and the partial area in the discharge area You may provide the 1st member which makes | forms the inner wall surface of the said 2nd developer storage chamber by providing along the inner wall surface of the 2nd developer storage chamber.

  In a preferred aspect of the present invention, the second transport member includes a spiral portion formed in a spiral shape that rotates about a rotation center, and the first member is the innermost member in the second developer accommodating chamber. It may be provided so as to cover the inner wall surface on the downstream side in the rotation direction of the spiral portion and on the vertical direction side from the center of the second developer storage chamber as viewed from the lower position.

  In a preferred aspect of the present invention, the first member is provided movably between a first position that covers the discharge port and a second position that does not cover the discharge port. When being moved to the position, it is downstream in the rotational direction of the spiral portion when viewed from the lowermost position in the second developer accommodating chamber and is perpendicular to the center of the second developer accommodating chamber. The inner wall surface on the side may be covered.

  In a preferred aspect of the present invention, the second developer accommodating chamber may have a cross-sectional area in the partial area in the discharge area smaller than a cross-sectional area in an area other than the partial area. Good.

  In a preferred aspect of the present invention, the second conveying member may have an outer diameter in the partial area in the discharge area larger than an outer diameter in an area other than the partial area.

  In a preferred aspect of the present invention, the second transport member includes a spiral blade provided around the center of rotation, and the spiral pitch of the blade in the partial region in the discharge region is the one. It may be shorter than the helical pitch in the region other than the region of the part.

  In a preferred aspect of the present invention, the second transport member is provided around the rotation center in the spiral blade provided around the rotation center, and in the partial area in the discharge area, You may provide the 2nd member which reduces the space in an area | region.

  The present invention also provides an image carrier, a charging unit for charging the surface of the image carrier, an exposure unit for exposing the surface of the image carrier charged by the charging unit to form a latent image, The developing device according to any one of the above, which develops the latent image formed by the exposure unit, the transfer unit that transfers the image developed by the developing device to a recording medium, and the transfer unit that has been transferred to the recording medium by the transfer unit An image forming apparatus comprising: a fixing unit that fixes an image.

  According to the present invention, it is possible to make it difficult for the developer that has entered from the discharge port of the developing device to be mixed into the developer contained in the developing device.

[Configuration of Image Forming Apparatus]
FIG. 1 is a diagram illustrating a configuration of an image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 performs image formation by a so-called tandem method. As shown in FIG. 1, the image forming apparatus 1 includes a control unit 11, a display operation unit 12, a communication unit 13, a sheet storage unit 14, image forming units 15 </ b> Y, 15 </ b> M, 15 </ b> C, 15 </ b> K, and a transfer unit 16. And a fixing unit 17. In the description of the present embodiment and the drawings, the configurations with reference numerals including the characters “Y”, “M”, “C”, and “K” are yellow (Y), magenta (M), and cyan, respectively. (C) means that the image formation is performed using the developer of each color of black (K).

  The control unit 11 includes a CPU (Central Processing Unit) and a memory, and controls each unit of the image forming apparatus 1 by executing a program stored in the memory. The display operation unit 12 includes a touch panel and operation buttons, displays an image according to an instruction from the control unit 11, and supplies an operation signal corresponding to an operation by the user to the control unit 11. The communication unit 13 acquires image data and the like from a computer device connected via a network, and supplies this to the control unit 11. The paper storage unit 14 stores paper cut into a predetermined size such as A3 or A4. The sheets stored in the sheet storage unit 14 are taken out one by one in accordance with an instruction from the control unit 11 and conveyed to the secondary transfer roll 62 of the transfer unit 16 through the sheet conveyance path.

  The image forming units 15Y, 15M, 15C, and 15K are arranged in series along the intermediate transfer belt 61 of the transfer unit 16, and form a toner image corresponding to the image data supplied by the control unit 11. Since the image forming units 15Y, 15M, 15C, and 15K have the same configuration, the configuration will be specifically described by taking the image forming unit 15Y as an example.

  The image forming unit 15Y includes a photosensitive drum 10Y, a charger 20Y, an exposure unit 30Y, a developing device 40Y, a primary transfer roll 50Y, and a cleaning member 60Y. The photoconductive drum 10Y is an image holding body on which a toner image is formed, and is rotated by a driving unit (not shown). The charger 20Y uniformly charges the surface of the photoreceptor drum 10Y. The exposure unit 30Y irradiates the charged surface of the photosensitive drum 10Y with a laser beam corresponding to the image data to form an electrostatic latent image. The developing device 40Y contains a two-component developer containing toner and carrier supplied from the developer supply unit 4Y. The developing device 40Y conveys the developer while stirring, thereby attaching the toner to the photosensitive drum 10Y on which the electrostatic latent image is formed, thereby forming a toner image. Thereby, the electrostatic latent image formed on the surface of the photosensitive drum 10Y is developed. The primary transfer roll 50Y transfers the toner image formed on the surface of the photosensitive drum 10Y to the intermediate transfer belt 61 due to a potential difference with the photosensitive drum 10Y. The cleaning device 60Y removes the toner remaining on the photosensitive drum 10Y after the toner image is transferred.

  The transfer unit 16 includes an intermediate transfer belt 61 and a secondary transfer roll 62. The intermediate transfer belt 61 is circulated by a driving roll (not shown), and conveys the toner image transferred and superimposed by the above-described primary transfer rolls 50Y, 50M, 50C, and 50K to the secondary transfer roll 62. The secondary transfer roll 62 transfers the toner image on the intermediate transfer belt 61 onto the sheet conveyed from the sheet storage unit 14 due to a potential difference with the intermediate transfer belt 61. The fixing unit 17 includes a heating roll 71 and a pressure roll 72, and heat and pressure are applied to the paper conveyed from the secondary transfer roll 62 to fix the toner image. The sheet on which the toner image is fixed is conveyed to a sheet discharge port through a sheet conveyance path, and is discharged from the sheet discharge port.

[Developer configuration]
Next, the configuration of the developing devices 40Y, 40M, 40C, and 40K will be described. Since each of the developing devices 40Y, 40M, 40C, and 40K has the same configuration, the configuration will be specifically described by taking the developing device 40Y as an example. In the following description, when it is not necessary to distinguish the developing devices 40Y, 40M, 40C, and 40K, they are collectively referred to as “developing device 40”.

  FIG. 2 is a plan view of the developing device 40Y viewed from above when the cover that covers the top of the developing device 40Y is removed. However, only the left part in the figure is a sectional view. As shown in the drawing, the developing device 40Y includes a developing roll 41, a developer accommodating chamber 42, and a developer accommodating chamber 43. The developing roll 41 is disposed in the vicinity of the developer accommodating chamber 43, and is provided so that a part thereof is exposed to the photosensitive drum 10Y side. The developer storage chamber 42 and the developer storage chamber 43 are adjacent to each other, and the opening Q as the first opening, the opening P as the second opening, and the third opening as the third opening. It communicates through the opening O.

  The developing roll 41 adsorbs the carrier contained in the developer in the developer accommodating chamber 43 by a magnetic force and rotates it by a driving unit (not shown) to convey the carrier to a developing region facing the photosensitive drum 10Y. . At this time, the toner contained in the developer adheres to the carrier. When the toner adhering to the carrier is conveyed to the developing area while being held by the developing roll 41, it moves to the photosensitive drum 10Y side due to a potential difference from the electrostatic latent image on the photosensitive drum 10Y. Thereby, the electrostatic latent image formed on the surface of the photosensitive drum 10Y is developed. In other words, the developing roller 41 holds the developer supplied from the developer storage chamber 43 and moves it to a position facing the photosensitive drum 10Y on which the electrostatic latent image is formed, thereby developing the developer. Take a role as a body.

  The developer accommodating chamber 42 is a cylindrical member extending in a direction parallel to the axial direction of the developing roll 41, and is a first developer accommodating chamber that accommodates a developer including toner and a carrier. Inside the developer accommodating chamber 42, a conveying member 420 provided with a blade, which is an example of a helical portion, around the rotation axis is provided as a first conveying member. The transport member 420 is transported in the direction of arrow A in the figure while stirring the developer stored in the developer storage chamber 42 by rotating the rotation shaft about a shaft center by a drive unit (not shown). To do. The developer conveyed to the conveying member 420 moves to the developer accommodating chamber 43 through the opening Q.

  The developer accommodating chamber 43 is a cylindrical member extending in a direction parallel to the axial direction of the developing roll 41, like the developer accommodating chamber 42 described above, and is a second member that accommodates a developer containing toner and a carrier. This is a developer storage chamber. Inside the developer accommodating chamber 43, a conveying member 430 provided with a blade, which is an example of a spiral portion, around the rotation axis is provided as a second conveying member. The developer storage chamber 43 discharges the developer, a transport region R1 that transports the developer to the developing roll 41, a staying region R2 that moves the developer from the opening P to the developer storage chamber 42, and the like. And a discharge area R3. In the transport region R1 and the stay region R2, the direction of the blades of the transport member 430 is partially reversed. The transport member 430 is rotated by a drive unit (not shown) with the rotation axis as the center, but the direction of the blades is reversed, so that the transport region R1 is stored in the developer storage chamber 43. The developer being conveyed is conveyed in the direction of arrow B in the figure while being agitated, and the developer is conveyed in the direction opposite to the direction of arrow B, that is, in the direction of arrow A in the staying region R2.

  In the transport region R1, the developer stored in the developer storage chamber 43 is supplied to the surface of the developing roll 41 while being transported in the direction of arrow B in the drawing while being stirred by the transport member 430. At this time, the developer that has not been supplied to the developing roll 41 is conveyed as it is to the staying region R2. The developer transported to the staying region R2 is pushed back in the direction opposite to the direction transported so far by the transport member 430, and thereby moves to the developer storage chamber 42 through the opening P. Also in the vicinity of the opening Q, the developer that has been transported up to that time by the transport member 420 moves to the developer storage chamber 43 through the opening Q on the same principle as in the vicinity of the opening P. In this way, the developer stored in the developing device 40Y circulates between the developer storage chamber 42 and the developer storage chamber 43.

  3 is a cross-sectional view of the discharge region R3 of the developer storage chamber 43 as viewed from the H direction shown in FIG. As shown in the drawing, in the discharge region R3 of the developer storage chamber 43, a developer supply port E is provided above, and a discharge port D is provided below the developer supply port E. Further, the discharge port D is opened. A shutter 435 for closing and closing is provided. The developer supply port E is an opening that receives supply of developer from the developer supply unit 4Y. As shown in the drawing, the opening O described above is provided at a position opposite to the side where the opening P is present when viewed from the position of the discharge port D, and the developer accommodating chamber 42 and the developer accommodating chamber 43 are provided. And communicate with each other. The developer supplied into the developer storage chamber 43 from the developer supply port E is immediately pushed in the direction of the opening O by the rotating conveying member 430 and moves to the developer storage chamber 42 through the opening O. It is like that.

  The discharge port D is an opening through which excess developer is discharged when the amount of developer stored in the developing device 40 exceeds a predetermined amount. The discharge port D is provided at a position opposite to the side where the opening Q is seen from the position of the opening P. In the staying region R2 described above, when the amount of developer stored in the developing device 40Y exceeds a predetermined amount, the surplus developer gets over the developer pushed back by the conveying member 430 and enters the discharge region R3. It comes to flow. The developer that has flowed into the discharge region R3 is transported in the direction of arrow B in the drawing by the transport member 430, and is discharged from the discharge port D to the outside of the developing device 40Y.

  The shutter 435 is provided along the inner wall surface of the developer accommodating chamber 43 and has a thickness that is between the inner wall surface of the developer accommodating chamber 43 and the outer edge of the blades of the conveying member 430. That is, the shutter 435 serves as a first member that forms the inner wall surface of the developer accommodating chamber 43 by being provided along the inner wall surface of the developer accommodating chamber 43. A two-dot chain line in the drawing represents the shutter 435 on the front side of the drawing.

  Here, FIG. 4 is a perspective view showing the shape of the shutter 435 when viewed from the back side of the paper surface of FIG. As shown in the figure, the shutter 435 is provided with a protruding portion T1 having a size larger than the discharge port D and a protruding portion T2, and a notch provided between the protruding portion T1 and the protruding portion T2. The portion T3 is approximately the same size as the discharge port D. While the developing device 40 is operating, the shutter 435 is moved to the second position where the notch T3 overlaps the discharge port D. That is, the protrusion T1 is disposed between the discharge port D and the opening P, and the protrusion T2 is disposed between the discharge port D and the opening O. At this time, since the discharge port D is opened toward the outside of the developing device 40, excess developer is discharged from the opening O. On the other hand, for example, when a lever (not shown) is operated by an operator during maintenance work, the shutter 435 is moved in the direction of arrow B in FIG. 3 by a slide mechanism or the like. At this time, since the shutter 435 moves to the first position where the protruding portion T1 covers the discharge port D, the discharge port D is closed toward the outside of the developing device 40. Therefore, the developer is not discharged from the discharge port D, and the developer and other foreign matters do not enter through the discharge port D from the outside.

  FIG. 5 is a cross-sectional view of the developer containing chamber 43 taken along the broken line J shown in FIG. As shown in the figure, the projecting portion T1 of the shutter 435 covers the developer retention area indicated by the arrow I in the figure. Similar to the projecting portion T1, the projecting portion T2 also covers the developer retention area represented by the arrow I. The developer retention area is a position where the developer is easily accumulated when the conveying member 430 is rotating clockwise as shown in the drawing. The developer is transported by the transport member 430 from the back side to the front side in the direction perpendicular to the paper surface of the drawing. At this time, the transport member 430 rotates clockwise, so that the development is performed in the region on the right side in the drawing. The agent is transported while moving leftward. For this reason, the developer tends to accumulate in the lower left side of the storage space of the developer storage chamber 43, that is, between the 6 o'clock direction and the 9 o'clock direction in the drawing. This developer retention region may be obtained by experiments or calculations.

  Here, a mechanism for collecting the developer discharged from the discharge port D of each developing device 40 will be described. FIG. 6 is a view of the developing devices 40Y, 40M, 40C, and 40K as viewed from above. A collection path 8 is provided at the tip of the discharge port D of each developing device 40. Inside the collection path 8 is provided a conveying member 81 provided with spiral blades around the rotation axis. The transport member 81 is transported in the direction of arrow C in the drawing by being rotated around a shaft center by a drive unit (not shown). The developer discharged from the discharge port D of each developing device 40 flows down to the recovery path 8 and is then transported to the recovery container 9 by the transport member 81. The developer conveyed to the collection container 9 is discarded as a deteriorated developer.

  For example, assume that the image forming apparatus 1 forms a black and white image. In this case, only the developing device 40K operates to perform the development, and accordingly, the excess K developer is discharged from the discharge port D of the developing device 40K. The K developer discharged from the discharge port D of the developing device 40K flows down to the recovery path 8 and is then transported to the recovery container 9 by the transport member 81. However, some of the K developer may move out of the collection path 8 and move in the direction of the discharge port D of the developing devices 40Y, 40M, and 40C. This is because, when a black and white image is formed, the developing devices 40Y, 40M, and 40C are not operating, and no developer flows from the respective discharge ports D to the collection path 8. . The developer that has moved in the direction of the discharge port D of the developing devices 40Y, 40M, and 40C enters the developer storage chamber 43 from each discharge port D. In this manner, when different color developers discharged from the other developing devices 40 enter from the discharge port D, different color developers are mixed into the developers stored in the developer storage chambers 42 and 43. There is a fear. The shutter 435 provided in the developer accommodating chamber 43 of each developing device 40 plays a role to prevent this mixing even when the discharge port D is open to the outside. Yes.

  Next, the operation of the shutter 435 at this time will be described with reference to FIG. 3 again. As described above, the different colors of the developer that have entered from the discharge port D pass through the gap between the developer accommodating chamber 43 and the conveying member 430, and the developer accommodating chamber from the opening O or the opening P. Try to move to 42. However, as shown in the drawing, in the region extending from the discharge port D to the opening P, the gap Y1 between the developer accommodating chamber 43 and the conveying member 430 is provided along the inner wall surface of the developer accommodating chamber 43. It is narrowed by the projected part T1. Further, in the region extending from the discharge port D to the opening O, the gap Y2 between the developer accommodating chamber 43 and the conveying member 430 is formed by a protrusion T2 provided along the inner wall surface of the developer accommodating chamber 43. It is narrowed. As described above, in a partial region in the discharge region R3 between the discharge port D and the openings P and O, the volume of the space between the developer storage chamber 43 and the transport member 430 is the discharge region. Since it is smaller than the volume in the other region in R3, the developer that has entered from the discharge port D is less likely to enter first from the region in which the volume is reduced. As a result, it is possible to prevent the developer that has entered from the discharge port D from entering the developer storage chamber 42 through the opening P or the opening O and mixing into the developer used for development as much as possible. it can.

  In addition, when the cross section of the storage space of the developer storage chamber 43 is viewed, the protrusions T1 and T2 are provided so as to cover the developer retention region as described above, and thus the configuration is not such. Compared to the case, in this developer retention region, the volume of the space between the retained developer and the transport member 430 is reduced. As a result, there is no space in which the developer that has entered from the discharge port D stays, and it is difficult to stay in the developer storage chamber 43.

[Modification]
The above is the description of the embodiment, but the contents of this embodiment can be modified as follows. Moreover, you may combine the following each aspect suitably.
(Modification 1)
In the embodiment described above, the shutter 435 has been moved in the direction of arrow B in FIG. 3, but the movement direction of the shutter 435 is not limited to this. For example, when there is a sufficient space between the outlet D and the opening O, the shutter may be moved in the direction opposite to the arrow B direction in FIG. In this case, the protrusion T2 shown in FIG. 4 has a size larger than the discharge port D, and the protrusion T2 covers the discharge port D.
Alternatively, when the portion adjacent to the notch T3 of the shutter 435 shown in FIG. 4 is made larger than the outlet D, the inner wall surface of the developer accommodating chamber 43 when the shutter 435 is viewed from the X direction of FIG. It may be configured to be rotatable along In this case, the discharge port D can be covered by rotating the shutter 435 counterclockwise, and conversely, the discharge port D can be opened by rotating the shutter 435 clockwise. Can do. In short, the shutter 435 may be provided so as to be movable between a first position that covers the discharge port D and a second position that does not cover the discharge port D.

(Modification 2)
In the above-described embodiment, the developer retention area is defined between the 6 o'clock direction and the 9 o'clock direction represented by the arrow I in FIG. 5, but is not limited thereto. For example, when the conveying member 430 rotates counterclockwise in FIG. 5, the developer staying region may be between the 3 o'clock direction and the 6 o'clock direction in the drawing. This is because the developer easily collects in the rotation direction side range of the transport member when viewed from the lowermost position of the storage space of the developer storage chamber 43. In short, the developer retention area is at least a range on the downstream side in the rotation direction of the conveying member 430 and the vertical direction side from the center of the developer storage chamber 43 when viewed from the lowermost position in the developer storage chamber 43. It only has to be included. The shutter 435 may be provided so as to cover the developer retention area.

(Modification 3)
In the above-described embodiment, the case where the developer storage chamber 42 and the developer storage chamber 43 communicate with each other via the three openings O, P, and Q has been described. On the other hand, when the developer storage chamber 42 and the developer storage chamber 43 communicate with each other through only two openings P and Q, the shutter 435 may not include the protrusion T2. This is because if the opening O is not provided, it is sufficient to narrow only the gap Y1 extending from the discharge port D to the opening P. Even in this configuration, it is possible to make it difficult for the developer that has entered from the discharge port D of the developing device 40 to be mixed into the developer contained in the developing device 40 as in the above-described embodiment.

(Modification 4)
In the above-described embodiment, the shutter 435 is provided in the developer accommodating chamber 43. However, instead of the shutter 435, a plate-like member along the inner wall surface of the developer accommodating chamber 43 in a partial region of the discharge region R3. May be provided. In this case, since the plate-like member does not need to move, the plate-like member may be welded to the inner wall surface of the developer storage chamber 43. FIG. 7 is a view showing an example of the plate-like members 436a and 436b according to this modification, and the two-dot chain line in the drawing shows the plate-like members 436a and 436b. As shown in the drawing, the plate-like member 436a is disposed between the discharge port D and the opening P, similarly to the above-described protrusion T1, and the plate-like member 436b is connected to the above-described protrusion T2. Similarly, it is disposed between the discharge port D and the opening O. That is, since the plate-like member 436 a and the plate-like member 436 b are provided at positions facing each other with the discharge port D interposed therebetween, the discharge port D is opened toward the outside of the developing device 40. FIG. 8 is a cross-sectional view of the developer storage chamber 43 taken along the broken line J shown in FIG. As shown in the figure, the plate-like member 436a is provided with a width corresponding to the developer retention area so as to cover the developer retention area represented by the arrow I in the figure. Similarly to the plate-like member 436a, the plate-like member 436b is also provided with a width corresponding to the developer retention region so as to cover the developer retention region represented by the arrow I. In this modified example, the plate-like members 436a and 436b are not limited to the shapes shown in FIGS. 7 and 8, and are provided, for example, so as to go around the inner circumference of the developer storage chamber 43 along the inner wall surface thereof. It may be a ring-shaped one. Even in this configuration, the gap Y1 that continues from the discharge port D to the opening P and the gap Y2 that continues from the discharge port D to the opening O can be narrowed.

(Modification 5)
In the above-described embodiment, the shutter 435 provided in the developer storage chamber 43 plays a role of preventing the mixing of different color developers that have entered from the discharge port D. On the other hand, the developer storage chamber 43 itself may play this role. FIG. 9 is a view showing an example of the developer storage chamber 44 according to this modification. As shown in the figure, in a part of the discharge region R3 of the developer storage chamber 44, recesses V1 and V2 that are recessed toward the conveying member 430 are provided so as not to interfere with the conveying member 430. The depression V1 is provided between the discharge port D and the opening P, and the depression V2 is provided between the discharge port D and the opening O. That is, the hollow portion V1 and the hollow portion V2 are provided at positions sandwiching the discharge port D. As a result, in the discharge region R3 of the developer storage chamber 44, the vertical sectional areas L1 and L2 in the recessed portions V1 and V2 are smaller than the vertical sectional area L3 in the region other than the recessed portions V1 and V2. The gaps Y1 and Y2 extending from the discharge port D to the openings P and O can be narrowed. Further, in this modification, the discharge region R3 of the developer storage chamber 44 may be provided with only a recess portion that is continuously recessed from the recess portion V1 to the recess portion V2. According to this configuration, the developer entering from the discharge port D of the developing device 40 is less likely to be mixed into the developer accommodated in the developing device 40 without adding a new member to the developer containing chamber. can do.

(Modification 6)
In the above-described embodiment, the shutter 435 provided in the developer storage chamber 43 plays a role of preventing the mixing of different color developers that have entered from the discharge port D. On the other hand, the transport member 430 may play this role. Next, some configurations of the conveying member 430 according to this modification will be exemplified.

  FIG. 10 is a diagram illustrating an example of the conveying member 431 according to this modification. As shown in the figure, the conveying member 431 is provided around the rotation axis in a range K1 between the discharge port D and the opening P and a range K2 between the discharge port D and the opening O. The diameter of the blade is larger. Here, “between the discharge port D and the opening P or the opening O” includes a range corresponding to the position where the discharge port D is provided. Thereby, in a partial region of the discharge region R3, the gap Y1 continuing from the discharge port D to the opening P and the gap Y2 continuing from the discharge port D to the opening O can be narrowed. In this modification, the conveying member 431 may have a blade diameter continuously increasing from the range K1 to the range K2.

  FIG. 11 is a diagram illustrating an example of the conveying member 432 according to this modification. As shown in the figure, the diameter of the rotation shaft of the conveying member 432 increases in a range K1 between the discharge port D and the opening P and a range K2 between the discharge port D and the opening O. ing. Thereby, in a partial region of the discharge region R3, the gap Y1 continuing from the discharge port D to the opening P and the gap Y2 continuing from the discharge port D to the opening O can be narrowed. In this modification, the conveying member 432 may have a continuously increasing diameter of the rotation shaft from the range K1 to the range K2. In the examples shown in FIGS. 10 and 11, the outer diameter of the conveying member in the range K1 and the range K2 is made larger than the outer diameter of the conveying member in the range other than the ranges K1 and K2 in the discharge region R3. The gaps Y1 and Y2 are narrowed.

  FIG. 12 is a diagram illustrating an example of the transport member 433 according to this modification. As shown in the figure, the conveying member 433 is provided around the rotation axis in a range K1 between the discharge port D and the opening P and a range K2 between the discharge port D and the opening O. The spiral pitch of the blades is shorter. As a result, in the range K1 and the range K2, the volume between the developer storage chamber 43 and the transport member 433 is reduced, and the transport force of the transport member 433 is further reduced. Becomes difficult to move to the opening P or the opening O. Further, in this modification, the conveying member 433 may have the spiral pitch of the blades continuously shortened from the range K1 to the range K2.

  FIG. 13 is a diagram illustrating an example of the transport member 434 according to this modification. As shown in the figure, the rotation shaft of the transport member 434 is provided with projecting members 437a and 437b along the direction of the rotation shaft. The protruding member 437a is disposed between the discharge port D and the opening P, and the protruding member 437b is disposed between the discharge port D and the opening O. That is, the protruding members 437a and 437b play a role as second members provided around the rotation axis in a part of the region within the discharge region R3. As a result, in the range where the protruding members 437a and 437b are disposed, the volume between the developer storage chamber 43 and the transport member 434 is reduced, and further, the transport force of the transport member 434 is reduced. It becomes difficult for the developer that has entered from the position to move to the opening P or the opening O. The shape of the protruding members 437a and 437b is not limited to the example shown in the figure, and any shape can be used as long as it is provided around the rotation shaft and reduces the volume between the conveying member 430 and the developer storage chamber 43. It may be a simple shape. Further, in this modified example, the projecting member may be continuously arranged on the rotation shaft of the conveying member 434 from the position where the projecting member 437a is disposed to the position where the projecting member 437b is disposed. Further, the protruding member may be formed as a protrusion formed integrally with the conveying member as in the present modification, or may be realized by attaching a separate member from the conveying member.

  According to the configuration according to this modification, the developer that has entered from the discharge port D from the developing device 40 is changed into the developing device 40 only by changing the shape of the conveying member provided in the developer containing chamber 43. It can be made difficult to mix in the developer stored therein.

(Modification 7)
In the embodiment described above, the discharge port D is provided in the developer storage chamber 43 that is adjacent to the developer storage chamber 42 and supplies the developer to the developing roll 41. However, this is not necessarily the case. A discharge port D may be provided in the storage chamber 42. That is, the developing roll 41 performs development using the developer supplied from the developer storage chamber (that is, the second developer storage chamber) in which the discharge port D is provided as in the above-described embodiment. Alternatively, as in this modification, development is performed using a developer supplied from a developer storage chamber (that is, the first developer storage chamber) in which the discharge port D is not provided. Also good.

(Modification 8)
In the embodiment described above, the transport member 430 is provided with spiral blades around the rotation axis, but is not limited thereto. For example, the conveying member 430 may be a so-called coil auger that does not have a rotating shaft and is formed by forming a linear member in a coil shape. In short, the transport member 430 only needs to include a spiral portion formed in a spiral shape that rotates about the rotation center.

1 is a diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. It is the top view which looked at the developing device when the cover which covers an upper part was removed from the upper part. It is sectional drawing which shows the discharge area | region of a developer storage chamber. It is a perspective view which shows the shape of a shutter. FIG. 3 is a cross-sectional view of a developer storage chamber. It is the figure which looked at the developing device from the upper part. It is a figure which shows an example of the plate-shaped member which concerns on a modification. It is sectional drawing of the developer storage chamber which concerns on a modification. It is a figure which shows an example of the developer storage chamber which concerns on a modification. It is a figure which shows an example of the conveyance member which concerns on a modification. It is a figure which shows another example of the conveyance member which concerns on a modification. It is a figure which shows another example of the conveyance member which concerns on a modification. It is a figure which shows another example of the conveyance member which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 11 ... Control part, 12 ... Display operation part, 13 ... Communication part, 14 ... Paper storage part, 15Y, 15M, 15C, 15K ... Image forming unit, 10Y ... Photosensitive drum, 20Y ... Charger 30Y ... exposure section, 40Y ... developing device, 50Y ... primary transfer roll, 60Y ... cleaning member, 16 ... transfer section, 61 ... intermediate transfer belt, 62 ... secondary transfer roll, 17 ... fixing section, 71 ... heating roll, 72 ... Pressure roll, 41 ... Development roll, 42-44 ... Developer storage chamber, O, P, Q ... Opening, 420,430-434 ... Conveying member, E ... Developer supply port, D ... Discharge port, 435 ... Shutter, 436a, 436b ... Plate member, 437a, 437b ... Projection member

Claims (10)

A first developer storage chamber and a second developer storage chamber for storing the developer;
A first opening and a second opening for communicating the first developer storage chamber and the second developer storage chamber;
Provided inside the first developer accommodating chamber and transporting the developer accommodated in the first developer accommodating chamber to the second developer accommodating chamber through the first opening. A first conveying member to be moved;
Provided inside the second developer accommodating chamber and transporting the developer accommodated in the second developer accommodating chamber to the first developer accommodating chamber through the second opening. A second transport member to be moved;
In the second developer accommodating chamber, the second developer accommodating chamber is provided at a position opposite to the side where the first opening is seen from the position of the second opening, and accommodated in the second developer accommodating chamber. A discharge port for discharging a part of the developed developer to the outside of the apparatus,
The developer supplied from the first developer storage chamber or the second developer storage chamber is held, and the developer is moved to a position facing the image carrier on which the latent image is formed. A developer holder for developing,
The second developer storage chamber includes a position where the discharge port is provided, and has a discharge region for discharging the developer from the discharge port.
In a partial area of the discharge area between the discharge port and the second opening, the volume between the second developer storage chamber and the second transport member is the discharge area. A developing device, wherein the volume is smaller than the volume in a region other than the partial region. A third side is provided at a position opposite to the side having the second opening as viewed from the position of the discharge port, and communicates the first developer storage chamber and the second developer storage chamber. With an opening of
In a part of the discharge area between the discharge port and the third opening, the volume between the second developer storage chamber and the second transport member is the discharge volume. The developing device according to claim 1, wherein the volume is smaller than the volume in a region other than the partial region in the region. The second developer containing chamber has a thickness that fits between an inner wall surface of the second developer containing chamber and an outer edge of the second transport member, and the second developer containing chamber has a thickness within the part of the discharge region. The developing device according to claim 1, further comprising a first member that forms the inner wall surface of the second developer storage chamber by being provided along the inner wall surface. The second conveying member is
A spiral portion formed in a spiral shape that rotates around the rotation center,
The first member is on the downstream side in the rotation direction of the spiral portion and viewed from the lowermost position in the second developer accommodating chamber and on the vertical direction side from the center of the second developer accommodating chamber. The developing device according to claim 3, wherein the developing device is provided so as to cover the inner wall surface. The first member is
It is provided so as to be movable between a first position that covers the discharge port and a second position that does not cover the discharge port,
When it is moved to the second position, it is on the downstream side in the rotational direction of the spiral portion when viewed from the lowest position in the second developer storage chamber and in the second developer storage chamber. The developing device according to claim 4, wherein the inner wall surface on the vertical direction side from the center is covered. The cross section of the second developer storage chamber in the partial area in the discharge area is smaller than the cross sectional area in an area other than the partial area. The developing device described. The outer diameter of the second conveying member in the partial area in the discharge area is larger than the outer diameter in an area other than the partial area. Development device. The second conveying member is
It has a spiral blade provided around the center of rotation,
The developing device according to claim 1, wherein a spiral pitch of the blades in the partial area in the discharge area is shorter than a spiral pitch in an area other than the partial area. The second conveying member is
A spiral blade provided around the center of rotation;
The developing device according to claim 1, further comprising: a second member provided around the rotation center in the partial area in the discharge area and configured to reduce a space in the area. An image carrier,
Charging means for charging the surface of the image carrier;
Exposure means for exposing the surface of the image carrier charged by the charging means to form a latent image; and
The developing device according to claim 1, which develops a latent image formed by the exposure unit;
Transfer means for transferring an image developed by the developing device to a recording medium;
An image forming apparatus comprising: a fixing unit that fixes an image transferred to a recording medium by the transfer unit.

Images