JP2009122536A - Developing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To open and close an opening part, and to make a developer less likely to be retained. <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 via a first opening part and a second opening part. A shutter is provided in the second developer storage chamber. The shutter is provided so as to be placed between the inwall surface of the second developer storage chamber and the outer edge of a transport member and moved between a first position, where the second opening part is covered and a second position where the second opening part is not covered, and covers the inwall surface of the second developer storage chamber which is on the downstream side in the rotating direction of the transport member; and when viewed from the lowest position in the second developer storage chamber and on a side which is lower than the center of the second developer storage chamber in the direction of gravity, when the shutter is moved to the second position. <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 agitated for a long time in the developing device and deteriorating, a new developer is supplied from the developer supply port, and the excess developer is removed. A technique for discharging from an outlet is known. Japanese Patent Application Laid-Open No. 2005-228867 discloses a technique for preventing toner from being scattered from a toner supply port when a process cartridge including the development device is removed from the apparatus main body by providing a shutter that shields the toner supply port in the developing device. It is disclosed.
JP 2005-49900 A

By the way, in the developing device described above, the developer circulates between the first developer containing chamber and the second developer containing chamber in the developing device. At this time, in the vicinity of the opening that connects the first developer storage chamber and the second developer storage chamber, the developer may stay without moving in the direction in which it should originally move. When the developer stays in the vicinity of the opening, the developer is not circulated smoothly.
The present invention has been made in view of such a background, and an object of the present invention is to open and close an opening and to make it difficult to retain a developer.

  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 and second openings that communicate with each other, and the first developer accommodating chamber are provided inside the first developer accommodating chamber, and rotate about the rotation center to thereby enter the first developer accommodating chamber. A first conveying member that moves the accommodated developer to the second developer accommodating chamber through the first opening while conveying the developer, and is provided inside the second developer accommodating chamber. By rotating about the rotation center, the developer stored in the second developer storage chamber is transported and moved to the first developer storage chamber through the second opening. Supplied from the second conveying member and the first developer accommodating chamber or the second developer accommodating chamber A developer holding body that holds the developer to be developed and moves the developer to a position facing the image holding body on which the latent image is formed, and an inner wall surface of the second developer storage chamber Between the first position that covers the second opening and the second position that does not cover the second opening. When it is moved and moved to the second position, it is on the downstream side in the rotational direction of the second transport member when viewed from the lowest position in the second developer accommodating chamber and the second position. And a moving member that covers the inner wall surface on the lower side in the direction of gravity with respect to the rotation center of the two conveying members.

  In a preferred aspect of the present invention, the apparatus includes a discharge port for discharging a part of the developer stored in the second developer storage chamber to the outside of the apparatus, and the moving member moves to the first position. When it is set, the discharge port may be covered together with the second opening.

  In a preferred aspect of the present invention, a developer supply port through which developer is supplied from a developer supply source is provided, and when the moving member is moved to the first position, the second opening is provided. The developer supply port may be covered together with the portion.

  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, A developing device according to any one of the above, a transfer unit that transfers an image developed by the developing device to a recording medium, and a fixing unit that fixes the image transferred to the recording medium by the transfer unit. An image forming apparatus is provided.

  According to the present invention, the opening can be opened and closed, and the developer can be made difficult to stay.

[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 communicate with each other via an opening Q, an opening P serving as a first opening, and an opening O serving as a second opening. is doing.

  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 spiral blades 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 in which spiral blades are provided 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 when viewed from the H direction shown in FIG. In this figure, the conveying member 430 is shown outside the developer accommodating chamber 43 for easy understanding, but actually, it is provided inside the developer accommodating chamber 43 as shown in FIG. ing. As shown in the figure, 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, and further, in the vicinity thereof, A shutter 435 for opening and closing the discharge port D and the opening O is provided. The developer supply port E is an opening that receives supply of developer from the developer supply unit 4Y. The developer supplied into the developer accommodating chamber 43 through the developer supply port E is pushed in the direction of the opening O by the rotating conveying member 430 and moves to the developer accommodating chamber 42 through the opening O. It is supposed to be.

  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. 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.

[Configuration and operation of shutter]
Next, the configuration and operation of the shutter 435 will be described.
The shutter 435 is a moving member provided along the inner wall surface of the developer accommodating chamber 43, and the thickness thereof is such that it fits between the inner wall surface of the developer accommodating chamber 43 and the outer edge of the blade of the transport member 430. is there. Here, FIG. 4 is a plan view or an elevation view when the shutter 435 at the position shown in FIG. 3 is viewed from four directions. As shown in the figure, the shutter 435 is provided with a protruding portion T1, a protruding portion T2, and a ring portion T3. The ring portion T3 is a ring-shaped member having an outer shape that is the same as or slightly smaller than the inner diameter of the developer storage chamber 43. Protruding portions T1 and T2 extending in a direction parallel to the developer transport direction are provided on both sides of the ring portion T3. The protrusion T1 has a size larger than the discharge port D shown in FIG. In addition, a region where the protruding portion T1 is not provided when viewed from the ring portion T3 (a region corresponding to S1 in the drawing) is also larger than the discharge port D. Below, this area | region is called the notch part U1. The protrusion T2 has a size larger than that of the opening O shown in FIG. Further, a region where the protruding portion T2 is not provided when viewed from the ring portion T3 (a region corresponding to S2 in the figure) has a size larger than the opening O. Below, this area | region is called the notch part U2.

  The shutter 435 is connected to operating means such as a lever that can be operated by an operator. By operating the operating means, the shutter 435 rotates along the inner wall surface of the developer accommodating chamber 43. . FIG. 5 is a diagram illustrating a state when the shutter 435 is moved from the position illustrated in FIG. 3 to another position. Here, the position of the shutter 435 illustrated in FIG. 3 is referred to as a first position P1, and the position of the shutter 435 illustrated in FIG. 5 is referred to as a second position P2.

  While the developing device 40 is operating, the shutter 435 is moved to the second position P2 shown in FIG. At this time, the cutout portion U1 of the shutter 435 is disposed at a position where it overlaps the discharge port D, so that the discharge port D is opened toward the outside of the developing device 40. At this time, since the notch U2 of the shutter 435 is disposed at a position overlapping the opening O, the opening O is opened toward the developer storage chamber 42. As a result, surplus developer is discharged from the discharge port D, and the developer supplied to the developer supply port E is moved to the developer storage chamber 42 through the opening O.

  On the other hand, for example, when the operating means is operated by an operator during maintenance work, the shutter 435 rotates along the inner wall surface of the developer storage chamber 43 and moves to the first position P1 shown in FIG. Be made. At this time, since the protruding portion T1 of the shutter 435 is moved to a position covering the discharge port D, the discharge port D is closed toward the outside of the developing device 40. At this time, the protrusion T2 of the shutter 435 is moved to a position that covers the opening O, so that the opening O is closed toward the developer storage chamber 42. As a result, the developer does not leak from the discharge port D to the outside of the developing device 40, and the developer and other foreign matters do not enter the developer storage chamber 42 from the developer storage chamber 43 through the opening O.

  Here, the operation of the shutter 435 at the second position P2 will be described in more detail. As described above, the shutter 435 at the second position P2 has an action of moving the developer supplied to the developer supply port E to the opening O side and the excess developer to the discharge port D side. It has the effect of moving.

  First, with reference to FIG. 6, the operation of moving the developer supplied to the developer supply port E toward the opening O will be described. FIG. 6 is a cross-sectional view of the developer storage chamber 43 taken along the broken line J shown in FIG. As shown in the drawing, in the developer accommodating chamber 43, the inner wall surface located at a position facing the opening O is a developer retention region I1. The developer retention area I1 is a position where the developer supplied through the developer supply port E is likely to accumulate when the transport member 430 rotates clockwise in the drawing.

  As described above, the developer supplied to the developer supply port E is transported to the opening O side by the rotation of the rotating transport member 430 and moves to the developer storage chamber 42 through the opening O. It has become. At this time, since the conveying member 430 rotates clockwise, the blade moves the developer in the right region in the drawing to the left, and then conveys the developer to the opening O side while lifting the developer. become. While being lifted upward in the direction of gravity by the conveying member 430, the developer that has fallen from its blades due to the action of gravity falls to the lower left side of the accommodation space of the developer accommodation chamber 43. Therefore, at the 6 o'clock direction and 9 o'clock in the figure, which are the lower left side of the storage space of the developer storage chamber 43, that is, the downstream side in the rotation direction of the transport member 430 and the lower side in the gravity direction from the center of the transport member 430. The developer tends to collect on the inner wall surface between the two directions. The developer retention area I1 may be obtained by experiments or calculations.

  When the shutter 435 is moved to the second position P2, the projecting portion T2 is disposed so as to cover the inner wall surface of the developer retention region I1, as shown in FIG. Therefore, in this developer retention region I1, the gap Y1 between the shutter 435 that forms the inner wall surface of the developer storage chamber 43 and the transport member 430 is compared with the case where the shutter 435 is not provided at such a position. Becomes narrower. As a result, the space in which the developer supplied to the developer supply port E stays becomes narrow, and the developer can be quickly moved to the opening O side.

  Next, with reference to FIG. 7, the operation of moving the excess developer to the discharge port D side will be described. FIG. 7 is a cross-sectional view of the developer storage chamber 43 shown in FIG. 5 when viewed from the Y direction in the drawing. As described above, the excess developer is transported in the direction B in the drawing by the transport member 430 and discharged from the discharge port D to the outside of the developing device 40Y. However, some of the developer conveyed by the conveying member 430 may stay in the developer retention region I2 in the drawing without being discharged from the discharge port D.

  When the shutter 435 is moved to the second position P2, the ring portion T3 is arranged so as to cover the inner wall surface of the developer storage chamber 43 in the developer retention region I2, as shown in FIG. Therefore, in this developer retention region I2, the gap Y2 between the shutter 435 that forms the inner wall surface of the developer storage chamber 43 and the transport member 430 is compared with the case where the shutter 435 is not provided at such a position. Becomes narrower. As a result, there is no space in which the developer conveyed as the discharged developer stays, and the amount of stay can be reduced. As a result, the developer is quickly discharged from the discharge port D to the outside of the developing device 40. Can be moved to.

  Here, let us consider a case where the shutter 435 is not provided so as to cover the developer retention region I2. In this case, in the developer retention region I2, the gap between the developer storage chamber 43 and the transport member 430 is wider than the gap Y2 in the figure, and therefore the developer accumulates here. When the developer accumulates in the developer retention region I2 in the vicinity of the discharge port D, for example, the accumulated developer is discharged while the shutter 435 is moved to close the discharge port D. There is a risk of scattering from the outlet D to the outside of the developing device 40. The fact that the shutter 435 is moved so that the discharge port D is closed means that the maintenance work has already started, and therefore it is not desirable that the developer leaks from the discharge port D. As described above, such a situation can be prevented by moving the developer to be discharged from the discharge port D to the outside of the developing device 40 without staying in the developer retention region I2.

[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 both the function of opening and closing the discharge port D and the function of opening and closing the opening O, but is not limited thereto. For example, the shutter 435 may open and close only the opening O.
FIG. 8 is a perspective view showing an example of the shutter 436 according to this modification. As shown in the figure, the shutter 436 is provided with a protruding portion T2 and a ring portion T3. That is, the shutter 436 is obtained by removing the protruding portion T1 from the shutter 435 shown in FIG.

  FIG. 9 is a diagram illustrating a state when the shutter 436 is moved to the first position P1. At this time, since the protruding portion T2 of the shutter 436 is moved to a position covering the opening O, the opening O is closed toward the developer storage chamber 42. As a result, the developer and other foreign matters do not enter the developer accommodating chamber 42 from the developer accommodating chamber 43 through the opening O. On the other hand, FIG. 10 is a diagram illustrating a state when the shutter 436 is moved to the second position P2. At this time, since the notch U2 of the shutter 436 is disposed at a position overlapping the opening O, the opening O is opened toward the developer storage chamber 42. As a result, the developer supplied to the developer supply port E is moved to the developer storage chamber 42 through the opening O. The notch U2 is a configuration of the shutter 436 considered in the same manner as in the embodiment, and is a region where the protruding portion T2 is not provided when viewed from the ring portion T3.

  Next, an operation when the shutter 436 is moved to the second position P2 shown in FIG. 10 will be described with reference to FIG. FIG. 11 is a cross-sectional view of the developer storage chamber 43 taken along the broken line J shown in FIG. When the shutter 436 is moved to the second position P2, the protruding portion T2 is disposed so as to cover the developer retention region I1 as with the protruding portion T2 of the shutter 435 described above. Therefore, in this developer retention region I1, the gap Y1 between the shutter 436 that forms the inner wall surface of the developer storage chamber 43 and the transport member 430 is compared with the case where the shutter 436 is not provided at such a position. Becomes narrower. As a result, there is no space in which the developer supplied to the developer supply port E stays, and the amount of the stay can be reduced. As a result, the developer can be quickly moved to the opening O side. .

(Modification 2)
In the embodiment described above, the shutter 435 opens or closes the discharge port D and the opening O, but is not limited thereto. For example, the shutter 435 may open and close the opening O and the developer supply port E.
FIG. 12 is a perspective view showing an example of the shutter 437 according to this modification. As shown in the figure, the shutter 437 is provided with a protruding portion T4 and a ring portion T3. The protrusion T4 has a size larger than the region extending from the opening O shown in FIG. 3 to the developer supply port E, while the notch U4 also has a size larger than this region. The notch U4 is a configuration of the shutter 437 considered in the same manner as in the embodiment, and is a region where the protruding portion T4 is not provided when viewed from the ring portion T3.

  FIG. 13 is a diagram illustrating a state when the shutter 437 is moved to the first position P1. At this time, since the protruding portion T4 of the shutter 437 is moved to a position covering the developer supply port E and the opening O, the developer supply port E is closed toward the outside of the developing device 40, and The opening O is closed toward the developer storage chamber 42. As a result, the developer and other foreign matters do not enter the developer storage chamber 43 from the developer supply port E, and the developer and the other foreign matter enter the developer storage chamber 42 from the developer storage chamber 43 through the opening O. No foreign matter enters. On the other hand, FIG. 14 is a diagram illustrating a state when the shutter 437 is moved to the second position P2. At this time, the notch U4 of the shutter 437 is disposed at a position overlapping the developer supply port E and the opening O, so that the developer supply port E is open toward the outside of the developing device 40. At the same time, the opening O is opened toward the developer storage chamber 42. As a result, the developer supplied to the developer supply port E is moved into the developer accommodating chamber 43 and this developer is moved to the developer accommodating chamber 42 through the opening O.

  Next, the operation when the shutter 437 is moved to the second position P2 shown in FIG. 14 will be described with reference to FIG. FIG. 15 is a cross-sectional view of the developer containing chamber 43 taken along the broken line J shown in FIG. 14 when viewed from the direction of the arrow X. When the shutter 437 is moved to the second position P2, the protrusion T4 is Similarly to the protrusion T2 of the shutter 435 described above, the developer retention area I1 is disposed. Therefore, in the developer retention region I1, the gap Y1 between the shutter 437 that forms the inner wall surface of the developer storage chamber 43 and the transport member 430 is compared with the case where the shutter 437 is not provided at such a position. Becomes narrower. As a result, there is no space in which the developer supplied to the developer supply port E stays, and the amount of the stay can be reduced. As a result, the developer can be quickly moved to the opening O side. .

(Modification 3)
In the above-described embodiment, the developer retention region I1 is set between the 6 o'clock direction and the 9 o'clock direction in FIG. 6, but is not limited thereto. For example, when the conveying member 430 rotates counterclockwise in FIG. 6, the developer retention region I1 is between the 3 o'clock direction and the 6 o'clock direction in the drawing. This is because the conveyance member is located downstream in the rotation direction of the conveyance member when viewed from the lowermost position of the storage space of the developer accommodation chamber 43 and in the lower side in the gravity direction with respect to the rotation center of the conveyance member. This is because the force of the conveying member scooping up the developer and the force of dropping the developer due to the action of gravity antagonize with each other, and the developer tends to accumulate. In short, the developer retention area I1 is a downstream area in the rotation direction of the conveying member 430 and a lower area in the gravity direction from the center of the conveying member 430 when viewed from the lowermost position in the developer accommodating chamber 43. . The shutter 435 is provided so as to cover the developer retention region I1 with the discharge port D opened.

(Modification 4)
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 accommodating chamber 42 and the developer accommodating chamber 43 communicate with each other through only two openings P and Q, the shutter is provided so as to open and close the opening P. It may be done.

(Modification 5)
In the above-described embodiment, the developer supply port E, the discharge port D, and the shutter 435 are 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. This need not be the case, and the developer supply port E, the discharge port D, and the shutter 435 may be provided in the developer storage chamber 42. That is, the developing roll 41 is supplied from the developer storage chamber (that is, the second developer storage chamber) in which the developer supply port E, the discharge port D, and the shutter 435 are provided as in the above-described embodiment. The developer may be developed using a developer, or a developer storage chamber (that is, the first developer storage) in which the developer supply port E, the discharge port D, and the shutter 435 are not provided as in this modification. Development may be performed using a developer supplied from the chamber.

(Modification 6)
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 may be any member that rotates around the rotation center and transports the developer.

1 is a diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. FIG. 6 is a plan view of the developing device with the cover covering the top removed, as viewed from above. It is sectional drawing of the discharge area | region of a developer storage chamber. It is a top view thru | or an elevation when a shutter is seen from 4 directions. It is a figure which shows a mode when a shutter is moved to another position. It is a figure explaining the effect | action which moves a developing agent to the opening part side. It is a figure explaining the effect | action which moves the excess developer to the discharge port side. It is a perspective view which shows an example of the shutter which concerns on a modification. It is a figure which shows a mode when the shutter is moved to the 1st position. It is a figure which shows a mode when the shutter is moved to the 2nd position. It is a figure explaining an effect | action when the shutter is moved to the 2nd position. It is a perspective view which shows another example of the shutter which concerns on a modification. It is a figure which shows a mode when the shutter is moved to the 1st position. It is a figure which shows a mode when the shutter is moved to the 2nd position. It is a figure explaining an effect | action when the shutter is moved to the 2nd position.

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, 42,43 ... Developer storage chamber, O, P, Q ... Opening, 420,430 ... Conveying member, E ... Toner supply port, D ... Discharge port, 435-437 …shutter

Claims (4)

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;
The first opening is provided inside the first developer accommodating chamber and rotates around the rotation center to convey the developer accommodated in the first developer accommodating chamber. A first conveying member that is moved through to the second developer accommodating chamber,
The second opening is provided inside the second developer storage chamber and rotates around the rotation center to convey the developer stored in the second developer storage chamber. A second conveying member that is moved to the first developer accommodating chamber through
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;
A first position provided so as to fit between an inner wall surface of the second developer storage chamber and an outer edge of the second conveying member, and covering the second opening; and the second opening The second transport member when viewed from the lowermost position in the second developer accommodating chamber when the second transport member is moved to and from the second position that does not cover the second developer storage chamber. And a moving member that covers the inner wall surface on the downstream side in the rotation direction and on the lower side in the direction of gravity with respect to the rotation center of the second conveying member. A discharge port for discharging a part of the developer stored in the second developer storage chamber to the outside of the apparatus;
The developing device according to claim 1, wherein the moving member covers the discharge port together with the second opening when the moving member is moved to the first position. A developer supply port through which a developer is supplied from a developer supply source;
The developing device according to claim 1, wherein the moving member covers the developer supply port together with the second opening when the moving member is moved to the first position. 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
A developing device according to any one of claims 1 to 3,
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