JP2012168395A - Rotary developing apparatus and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress turbulence of a developer in a developing device caused through rotation of a rotary holder.SOLUTION: Each developing device 3 of a rotary developing apparatus 2 comprises: a developer holder 6 disposed to face a developing opening of a developer container 5 for holding and rotatively conveying a developer G; conveyance paths 7 (such as paths 7a and 7b) provided within the developer container 5 for conveying the developer G so that the developer G may be circulated between a portion facing the developer holder 6 and a portion not facing the developer holder 6; a plurality of stirring conveyance members 8 (such as members 8a and 8b) each of which has a spiral blade member 16 provided around a rotation shaft 15 extending along a rotational axis of the developer holder 6 in a part of the conveyance paths 7 and is rotated so as to stir and convey the developer G along the conveyance paths 7; and a projection part 10 that projects from an inner wall of the developer container 5 opposing at least some of the plural stirring conveyance members 8 and extends to be inclined in an opposite direction to inclination of the blade member 16 of the opposing stirring conveyance member 8.

Description

  The present invention relates to a rotary developing device and an image forming apparatus using the same.

As rotary developing devices used in conventional image forming apparatuses, those described in Patent Documents 1 to 3, for example, are already known.
In Patent Document 1, in order to prevent the toner in the conveyance path connecting between the toner container and the developing device from reversing due to the rotation of the developing rotary, when the toner is replenished during the next image formation, A technique for correcting the replenishment amount of toner according to the rotation pattern of the development rotary at the time of formation is disclosed.
In Patent Document 2, in order to provide a developing device in which the toner layer on the developer carrying member is not interrupted even when rocked, in the developing device having the developer carrying member in the housing, the volume in the housing is changed. There has been disclosed a technique for providing a volume adjusting means for changing the volume in the housing in accordance with the swing of the developing device and keeping the powder surface of the developer constant.
In Patent Document 3, the rotation amount is measured by a rotation amount measuring unit that measures the rotation amount of the rotating holder, a development drive amount measuring unit that measures a drive amount associated with the developing operation of each developing device, and a rotation amount measuring unit. A technology comprising idle drive control means for idling a low-use developer whose drive amount measured by the development drive amount measuring means is equal to or less than a predetermined value for a predetermined period according to the rotation amount of the rotating holder. Is disclosed.

JP 2004-271955 A (Embodiment of the Invention, FIG. 8) JP 2010-60778 A (Best Mode for Carrying Out the Invention, FIG. 2) JP 2008-233718 A (Best Mode for Carrying Out the Invention, FIG. 1)

  A technical problem to be solved by the present invention is to provide a rotary developing device that suppresses the disturbance of the developer in the developing device due to the rotation of the rotating holder, and an image forming apparatus using the same. .

  According to a first aspect of the present invention, there are provided a plurality of developing units for developing an electrostatic latent image having a predetermined color component held on an image holding member with a developer of a corresponding color, and rotating in a predetermined direction. A rotation holding body on which each developing device is mounted so that the plurality of developing devices are arranged in a rotation direction, a development position facing the image holding body, and a standby position other than the development position. The developer unit is set to the stop position, and one or a plurality of used developer units used in a series of image forming processes of single color or composite color are sequentially rotated to the development position, and the developer unit is stopped at the development position. While the developing device is driven to be developable, the rotation holding body and each of the developing devices are set so that the developing device that is finally located at the developing position in the image forming process by single color or composite color is returned to the predetermined initial standby position. Development control means for controlling the device Each of the developing devices has a developing opening facing the image carrier, and is disposed facing the developing opening of the developing container in which a two-component developer containing toner and a carrier is accommodated. And a developer holder that rotates and conveys the developer, and a developer that is provided in the developer container and that faces the developer holder and does not face the developer holder. A spiral blade member is provided and rotated around a transport path for transporting the developer so as to circulate, and a rotation shaft extending along the rotation axis direction of the developer holder in the transport path. A plurality of agitating and conveying members for agitating and conveying the developer along the conveying path, and an agitating and conveying that is provided in a convex shape on the inner wall of the developing container facing at least a part of the agitating and conveying members Opposite to the direction of blade inclination And a convex portion extending obliquely to the direction, a rotary developing apparatus comprising the.

According to a second aspect of the present invention, in the rotary developing device according to the first aspect, the convex portion is not in contact with the developer in the transport path when the developing unit having the convex portion is located at the development position. This is a rotary developing device.
According to a third aspect of the present invention, in the rotary developing device according to the first or second aspect, a plurality of the convex portions are provided at intervals with respect to the rotation axis direction of the stirring and conveying member. Type developing device.
According to a fourth aspect of the present invention, in the rotary developing device according to any one of the first to third aspects, the convex portion forms a concave portion on an inner wall of a member constituting the developing container, and the portion surrounded by the concave portion is a concave portion. The rotary developing device is projected relative to the bottom of the rotary developing device.
According to a fifth aspect of the present invention, in the rotary developing device according to any one of the first to fourth aspects, the convex portion is provided in a portion of the transport path that does not face the developer holder. Is a rotary developing device.
According to a sixth aspect of the present invention, in the rotary developing device according to any one of the first to fifth aspects, the convex portion is provided in a portion of the transport path facing the developer holder. Is a rotary developing device.
According to a seventh aspect of the present invention, in the rotary developing device according to any one of the first to sixth aspects, the convex portion has a rotational axis direction of the stirring and conveying member as compared to one pitch of the blade member of the opposing stirring and conveying member. A dimension of the rotary developing device is set to be long.
According to an eighth aspect of the present invention, in the rotary developing device according to any one of the first to seventh aspects, the part of the transport path corresponding to the upstream end in the transport direction of the developer by the stirring transport member and the stirring Protrusively provided on the inner wall of the developer container facing the conveying member, and has another convex portion that is inclined along the radial direction of the rotation axis of the stirring and conveying member or in the direction opposite to the inclination direction of the convex portion. The rotary developing device is characterized.

According to a ninth aspect of the present invention, in the rotary developing device according to any one of the first to eighth aspects, the developing device is provided in a part of the developing container and can be replenished with a new developer containing at least toner. This is a rotary developing device having a simple developer supply port.
According to a tenth aspect of the present invention, in the rotary developing device according to any one of the first to ninth aspects, the developing device is provided in a part of the developing container and replenished with a new developer containing toner and a carrier. And a developer discharge port provided in a part of the developer container and capable of discharging excess developer.
According to an eleventh aspect of the present invention, in the rotary developing device according to the tenth aspect, the convex portion faces an agitating and conveying member disposed in a conveying path that communicates with the developer discharge port, and at least the developer discharge. The rotary developing device is provided at a portion adjacent to the outlet.
According to a twelfth aspect of the present invention, in the rotary developing device according to any one of the ninth to eleventh aspects, the convex portion is provided to face an agitating / conveying member disposed in a conveying path leading to the developer supply port. The rotary developing device is characterized by that.
According to a thirteenth aspect of the present invention, an image carrier that selectively holds electrostatic latent images of a plurality of predetermined color components, and an image carrier that is provided opposite to the image carrier and is held by the image carrier. An image forming apparatus comprising: a rotary developing device according to any one of claims 1 to 12 that develops an electrostatic latent image of each color component with a developer of a corresponding color.
According to a fourteenth aspect of the present invention, in the image forming apparatus according to the thirteenth aspect, the development control means uses a predetermined use when a single color image forming process is continuously performed for a predetermined threshold value or more. An image forming apparatus comprising: an idle drive control unit that idles a low-use developer less than the number of times for a predetermined time idle drive.

According to the first aspect of the invention, it is possible to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder.
According to the second aspect of the present invention, it is possible to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder without affecting the developer transport behavior during the developing operation.
According to the third aspect of the present invention, it is possible to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder over a wide range.
According to the fourth aspect of the present invention, it is possible to sufficiently secure the developer conveyance space in the conveyance path, and to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder.
According to the fifth aspect of the present invention, it is possible to suppress the disturbance of the developer at a portion that does not face the developer holder in the developing device due to the rotation of the rotary holder.
According to the invention of claim 6, it is possible to suppress the disturbance of the developer at the portion facing the developer holding body in the developing device due to the rotation of the rotating holding body, and supply the developer holding body. The developer distribution can be kept substantially uniform.
According to the seventh aspect of the present invention, it is possible to secure a large amount of developer return by the convex portion during rotation of the rotary holder, and the rotation holder can be rotated as compared with an aspect without this configuration. The resulting disturbance of the developer can be suppressed more favorably.
According to the eighth aspect of the invention, as the behavior of the developer due to the rotation of the rotating holder, the deviation of the developer at the upstream end portion in the transport direction of the developer by the stirring transport member in the transport path is suppressed. be able to.
According to the ninth aspect of the present invention, even if the developing device replenishes the developer, it is possible to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder.
According to the tenth aspect of the present invention, even when the developing device replenishes and discharges the developer, it is possible to suppress the disturbance of the developer in the developing device due to the rotation of the rotating holder.
According to the eleventh aspect of the present invention, even when the developing device includes a transport path that leads to the developer discharge port, excessive discharge of the developer from the developer discharge port due to the rotation of the rotating holder. The phenomenon can be suppressed.
According to the twelfth aspect of the present invention, even when the developing device includes a transport path that leads to the developer supply port, development on the transport path that leads to the developer supply port caused by the rotation of the rotation holding member. Disturbance of the agent can be suppressed.
According to the invention of claim 13, it is possible to easily construct an image forming apparatus including a rotary developing device capable of suppressing the disturbance of the developer in the developing device due to the rotation of the rotary holder. it can.
According to the fourteenth aspect of the present invention, when the monochrome image forming process is continuously performed, it is assumed that the developer is disturbed in the low-use developing device due to a plurality of rotations of the rotating holder. However, it is possible to easily construct an image forming apparatus capable of effectively repairing the disturbance of the developer.

(A) is an explanatory view showing an outline of an embodiment of a rotary developing device to which the present invention is applied and an image forming apparatus using the rotary developing device, and (b) is a development mounted on the rotary developing device of (a). Explanatory drawing which shows the structural example of a container, (c) is the arrow line view seen from C direction in (b). (A) is a schematic diagram showing the developing device of FIG. 1 (b) in a plan view, and (b) is a diagram showing a rotation of a low-use developing device produced by a rotary developing device according to a comparative embodiment having no projections. FIG. 10 is an explanatory diagram showing a biasing operation of the developer at the time. 1 is an explanatory diagram illustrating a main part of an overall configuration of an image forming apparatus according to Embodiment 1. FIG. It is explanatory drawing which shows the detail of the developing device shown in FIG. FIG. 5 is a cross-sectional explanatory view taken along line VV in FIG. 4. (A) is explanatory drawing which shows the detail of the developer discharge port vicinity of Embodiment 1, (b) is the principal part perspective view. FIG. 4 is a perspective view showing an overall configuration of a developing device mounted on the rotary developing device shown in FIG. 3. FIG. 8 is an explanatory diagram illustrating a state where a developer supply container is removed from the developing device illustrated in FIG. 7. It is explanatory drawing which shows the developer supply container used by this Embodiment. It is explanatory drawing which shows a connection part with a developer supply container among the developing devices used by this Embodiment. FIG. 2 is a perspective view in which a developing unit used in Embodiment 1 is partially broken and an upper lid is partially shown by an imaginary line. (A) is explanatory drawing which looked at the upper cover of the developing container shown in FIG. 11 from the inner side, (b) is a sectional view taken along the line BB in (a). 11A is an explanatory plan view of the developing device shown in FIG. 11, and is an explanatory diagram partially showing the upper lid in phantom lines, and FIG. 11B is an explanatory diagram schematically showing the relationship between the agitation transport member and the guide convex portion. is there. FIG. 3 is an explanatory diagram showing a control system (drive control system, density control system) used in the first embodiment. FIG. 5 is an explanatory diagram showing the behavior of the developer in the developing device when the rotation holding body of the rotary developing device according to the first embodiment is rotated once. FIG. 16 is an explanatory diagram showing the behavior of the developer in the developing device shown in FIG. 15 in relation to the agitation transport member. FIG. 16 is an explanatory diagram schematically showing the behavior of the developer in the developing device shown in FIG. 15 in relation to the stirring and conveying member and the guide convex portion. FIG. 10 is a partially broken explanatory view showing a main part of a developing device mounted on a rotary developing device according to a second embodiment. It is explanatory drawing which looked at the upper cover of the developing container shown in FIG. 18 from the inside. FIG. 10 is a partially broken explanatory view showing a main part of a developing device mounted on a rotary developing device according to a third embodiment. It is explanatory drawing which looked at the upper cover of the developing container shown in FIG. 20 from the inside. (A) is explanatory drawing which shows the principal part of the developing device mounted in the rotary developing device which concerns on Embodiment 4, (b) is explanatory drawing which shows the relationship between a stirring conveyance member and a guide protrusion, (c). These are explanatory drawings which show the structural example of the guidance protrusion used in this Embodiment. FIG. 10 is an explanatory diagram illustrating an image quality defect inspection process associated with developer bias, which is an example of a control process employed in a rotary developing device according to a fifth embodiment. (A) is explanatory drawing which shows the bias state of the developer before idling of a low use developing device, (b) is explanatory drawing which shows the uniform state of the developer after idling of a low use developing device.

Outline of Embodiment First, an outline of an embodiment of an image forming apparatus to which the present invention is applied will be described.
FIG. 1A shows an outline of an embodiment of an image forming apparatus.
In FIG. 1, an image forming apparatus includes an image holding body 1 that selectively holds an electrostatic latent image of a plurality of predetermined color components, and an image holding body that is provided opposite to the image holding body 1. And a rotary developing device 2 that develops the electrostatic latent image of each color component held in 1 with a developer of a corresponding color.
The rotary developing device 2 includes a plurality of developing units 3 (3a to 3d) that develop an electrostatic latent image of a predetermined color component held on the image carrier 1 with a developer of a corresponding color, A rotation holder 4 that is provided so as to be rotatable in a predetermined direction and that mounts the developing devices 3 so that the plurality of developing devices 3 are arranged along the rotation direction, and faces the image carrier 1. The standby positions P _{2 to} P ₄ other than the development position P ₁ and the development position P ₁ are set as the stop positions of the respective development devices 3, and one or a plurality of used development devices 3 that are used in a series of image forming processes using single colors or composite colors. was rotated sequentially moved to the developing position P _1, while the developing device 3 is driven to be developed in a state where the developing unit 3 stops at the developing position P _1, the developing position imaging processing by the monochrome or composite color predetermined initial standby position the developing device 3 which is located in the end P ₁ Back to _0, and a developing control unit 20 for controlling the rotary holder 4 and the developing units 3.
In this type of rotary developing device 2, when no image forming job is performed, the developing devices 3 are initially placed on standby at an initial standby position P ₀ so that all the developing devices 3 do not face the development position P _1. Therefore, in many cases, care is taken to prevent the toner and the carrier from flowing out to the image carrier 1 and to prevent the developer from being accumulated, and to maintain the developing performance of each developing device 3 in good condition.

  In the present embodiment, the developing devices 3 (3a to 3d) of the rotary developing device 2 are opposed to the image carrier 1 as shown in FIGS. 1B, 1C, and 2A. A developing container 5 that has a developing opening and contains a two-component developer G containing toner and carrier, and is disposed facing the developing opening of the developing container 5 and holds and conveys the developer G. The developer G is circulated between the developer holding body 6 and the portion provided in the developer container 5 and facing the developer holding body 6 and the portion not facing the developer holding body 6. And a conveying path 7 (for example, 7a, 7b) for conveying the developer G, and a spiral blade member around a rotation shaft 15 extending along the rotation axis direction of the developer holder 6 in the conveyance path 7. 16 is provided and rotated to agitate and convey developer G along the conveyance path 7. A plurality of agitating and conveying members 8 (for example, 8a and 8b), and a blade member of the agitating and conveying member 8 provided in a convex shape on the inner wall of the developing container 5 facing at least a part of the agitating and conveying members 8 The convex part 10 inclines in the reverse direction with respect to 16 inclination directions, and is provided. In such a developing device 3, a developer replenishing mechanism and a developer discharging mechanism may be added as will be described later.

Here, in the rotary developing device 2 according to the comparative embodiment that does not have the convex portion 10 described above, as shown in FIG. 2B, a specific single color job (for example, a single color black job) is continuously performed. assuming cracking as, for each end of the single specific monochromatic job, the developing device 3 (e.g., the developing device 3a) is moved by rotating approximately 1 to an initial standby position P ₀ from the developing position P _1, the following When the specific monochrome job is designated, the specific monochrome job is performed again by moving from the initial standby position P ₀ to the development position P ₁ .
At this time, the developing device 3a to be used for the development has the developing position P ₁ → the standby position P ₂ → the standby position P ₃ → the standby position P ₄ → the initial stage in accordance with the rotation operation of the rotary holder 4 after the image forming job is completed. It moves from the standby position P _{0 to the} development position P ₁ . During one revolution before returning again to the developing position P _1, the developing unit agitation transport member 8 (8a, 8b) in 3a is located in the drive stopped state, agitation transport in accordance with the rotation of the rotary holder 4 member 8 The developer G in a portion corresponding to (for example, 8b) moves along the conveyance direction of the agitation conveyance member 8. However, in the developing device 3a used for the development, the developer G moved by the driving of the stirring and conveying member 8 (for example, 8b) accompanying the developing operation by the next image forming job is immediately leveled.
However, in the low-use developing device 3 (for example, 3b to 3d) that is not used for development for a long time and has a low number of times of use, as shown in FIG. 2B, the rotation of the rotating holder 4 is repeated a plurality of times. The agitating / conveying member 8 (8a, 8b) in the low-use developing device 3 (for example, 3b to 3d) is in a drive stop state, and the agitating / conveying member 8 (for example, 8b) is moved along with the multiple rotation operation of the rotating holder 4. The developer G in the corresponding part sequentially moves along the conveyance direction of the agitation conveyance member 8 (see arrow A in FIG. 2B). As described above, in the low-use developing device 3 (for example, 3b to 3d), the amount of movement of the developer G increases as the number of rotations of the rotating holder 4 increases, and the deviation of the developer G increases. Density will occur in the agent distribution. When the low-use developer 3 (for example, 3b to 3d) is subjected to development in a state where the deviation of the developer G exceeds a certain limit, the layer thickness of the developer G is regulated by the layer thickness regulating member. However, the layer thickness difference cannot be eliminated, and image quality defects such as density unevenness tend to occur.
In FIG. 2 (b), the return phenomenon of the developer G has been described by taking the stirring / transporting member 8b as an example. However, the phenomenon is not limited to this, and other stirring / transporting members 8a are not limited thereto. A similar return phenomenon of the developer G may occur.
Further, the bias phenomenon of the developer G described above may occur even when a specific single color job (for example, a single color black job) is continuously performed. For example, when a developer G is discharged to a specific developing device, when an operation of writing various types of operation information on a communicable recording medium is performed, or when an image forming position or image forming density is controlled. When image process control is performed, as the specific developing device is moved to the developing position, the other developing devices are also forcibly rotated. Therefore, the bias of the developer G in the low-use developing device Will be accelerated.
In this embodiment, in order to suppress such a return phenomenon of the developer G, the convex portion 10 is added as a constituent requirement of the developing device 3.

In such technical means, it is sufficient that the rotary holder 4 rotates in a predetermined direction, and the arrangement direction of the developing devices 3 mounted on the rotary holder 4 may be appropriately selected.
Further, as the development control means 20, at least a single color or composite color development operation is performed in accordance with an image formation instruction, and when the image formation process is completed, the rotation holder 4 is rotated, and each developing device 3 is moved to the initial standby position P. _Return to ₀ .
At this time, the initial standby position P ₀ of each developing device 3 may be appropriately selected. However, from the viewpoint of shortening the movement time of the developing device 3 to the developing position P ₁ , the developing device P ₁ is the most. It is preferable to arrange a high-use developing device 3 (for example, 3a) having a high use frequency in a nearby portion.
Further, the transport path 7 only needs to include at least a circulation transport path 7a through which the developer circulates. A branch transport path 7b branched from the circulation transport path 7a, for example, developer replenishment for transporting the replenishment developer. Of course, a route or the like may be provided.
Further, when the rotation holding body 4 is rotated once, there is a concern that the developer moves in the reverse flow direction along the blade member 16 of the stirring and conveying member 8, but the convex portion 10 is along the blade member 16 due to the inclination thereof. It works to return the moved developer to the original position. At this time, the amount of returning the developer to the original position is determined by the length and depth along the inclination direction of the convex portion 10, so that the amount of developer moving by one pitch of the blade member 16 can be restored. It is preferable to select.
Further, the convex portion 10 may be formed integrally with a member (for example, the upper lid 5a) constituting the inner wall of the developing container 5, or another member having the convex portion 10 may be provided. Here, it is sufficient that the convex portion 10 is provided on the inner wall of the developing container 5 in a convex shape. Of course, the convex portion 10 projects from the inner wall surface, but a concave portion is formed on the inner wall to relatively secure the convex portion. Thus, a mode that does not protrude from the inner wall surface is also included. Further, when the developing unit 3 is positioned at the developing position P _1, to the convex portion 10 of the developing device 3 can be a developer and a non-contact, may be in contact.
Furthermore, the convex portion 10 does not have to be provided to face all of the agitating / conveying members 8 (8a to 8c), and the developer in the conveying path 7 is likely to be disturbed as the rotating holder 4 rotates. In contrast, it may be provided mainly. Moreover, what is necessary is just to provide at least one convex part 10, and what is necessary is just to provide with two or more as needed.

Next, a typical aspect or a preferable aspect of the rotary developing device 2 according to the present embodiment will be described.
First, a preferred embodiment of the convex portion 10, when the developing device 3 with the projecting portion 10 is positioned at the developing position P _1, embodiment a non-contact and the like from the developer in the conveying path 7. In this embodiment, when the developing device 3 positioned at the developing position P _1, Upon convex portion 10 from being a developer and a non-contact in the transport path 7, to agitating and conveying the developer to the developing operation, the convex portion 10 Is preferable in that it does not become a resistance when the developer is conveyed.
Moreover, as another preferable aspect of the convex part 10, the aspect provided with two or more intervals with respect to the rotating shaft direction of the stirring conveyance member 8 is mentioned. Since each of the plurality of convex portions 10 returns the developer, if the plurality of convex portions 10 are provided, it is possible to widen the working area for returning the developer.
Furthermore, as a typical aspect of the convex portion 10, there may be mentioned one in which a concave portion is formed on the inner wall of the member constituting the developing container 5 and a portion surrounded by the concave portion is protruded relatively to the bottom of the concave portion. . In this embodiment, since the convex portion 10 does not protrude from the inner wall surface of the developing container 5, it is possible to secure a wide cross-sectional space for transporting the developer without contacting the convex portion 10 in the transport path 7.
Furthermore, as a typical arrangement example of the convex portion 10, there is an embodiment in which the convex portion 10 is provided in a portion of the conveyance path 7 that does not face the developer holder 6. In the part of the transport path 7 facing the developer holder 6, the developer is normally held by the developer holder 6 with a magnetic force or the like. Therefore, even if the rotary holder 4 rotates, the developer is not biased. Few. On the other hand, since the developer holding force does not work in a portion of the transport path 7 that does not face the developer holding body 6, the developer tends to be biased as the rotating holding body 4 rotates. In the embodiment, this can be suppressed.

Further, as another typical arrangement example of the convex portion 10, as shown by a two-dot chain line in FIG. 1B, an aspect provided in a portion 7 a facing the developer holding body 6 in the conveyance path 7 can be given. It is done. In the conveyance path 7, at the portion 7 a facing the developer holding body 6, when the developer flows back along the blade member 16 of the agitating and conveying member 8 (8 a) as the rotating holding body 4 rotates, the developer holding body. However, in this embodiment, the convex portion 10 suppresses such deviation of the developer.
Furthermore, as a preferable aspect of the convex part 10, the aspect along which the dimension along the rotating shaft 15 direction of the said stirring conveyance member 8 is set long compared with 1 pitch of the blade member 16 of the stirring conveyance member 8 which opposes is mentioned. . Regarding the configuration of the convex portion 10, it is necessary to select parameters such as length and depth so as to obtain a necessary developer return amount. However, in this embodiment, the length and depth of the convex portion 10 are sufficiently set. This is effective in securing a large amount of developer return under conditions that are difficult to ensure.
Furthermore, as a more preferable aspect of the aspect in which the convex part 10 is added, the part corresponding to the upstream end in the transport direction of the developer by the stirring transport member 8 in the transport path 7 and facing the stirring transport member 8. Other convex portions (not shown) that are provided on the inner wall of the developing container 5 in a convex shape and are inclined along the radial direction of the rotation shaft 15 of the stirring and conveying member 8 or in the direction opposite to the inclination direction of the convex portion 10. ). In this aspect, since the other convex portions do not perform the developer returning action like the convex portion 10 described above, even if the rotation holding body 4 rotates, the developer by the stirring and conveying member 8 in the conveying path 7 is rotated. The developer is not pushed back against the upstream end in the transport direction.

-Developer supply mechanism, developer discharge mechanism-
In the present embodiment, the developing device 3 mounted on the rotary developing device 2 includes a developer replenishing mechanism and a developer discharging mechanism.
As shown in FIG. 2A, the developer supply mechanism includes a developer supply port 11 provided in a part of the developing container 5 and capable of supplying a new developer containing at least toner. It is done. This type of developer replenishing mechanism is normally incorporated in the rotary developing device 2, but includes a mode provided outside, and at least has a developer replenishing port 11.
Here, in a mode in which only the developer supply mechanism is added, toner may be supplied as the supplied developer.
Further, in a mode in which a developer discharging mechanism is further added to this type of developer replenishing mechanism, the developing device 3 is provided in a part of the developing container 5 and has a new developer containing toner and carrier. Examples include a developer replenishing port 11 that can be replenished and a developer discharge port 12 that is provided in a part of the developing container 5 and that can discharge excess developer. In this embodiment, since the developing device 3 replenishes the developer and discharges the excess developer, the developer accommodated in the developing device 3 can be kept in a new state.
Further, as a preferable aspect of the aspect in which the developer discharge mechanism is added, the convex portion 10 is provided with the stirring and conveying member 8 (for example, 8b) disposed in the conveyance path 7 (circulation conveyance path 7a) leading to the developer discharge port 12. And at least a portion that is adjacent to the developer discharge port 12. In this aspect, the convex portion 10 suppresses the movement of the excess developer toward the developer discharge port 12 as the rotation holder 4 rotates.
Further, as a preferable aspect of the aspect in which the developer replenishing mechanism is added, for example, the convex portion 10 in FIG. 2B is disposed in the transport path 7 (in this example, the branch transport path 7b) leading to the developer replenishment port 11. In addition, a mode in which the agitating / conveying member 8 (for example, 8c) is provided. In this embodiment, the convex portion 10 suppresses the reverse flow phenomenon of the developer in the conveyance path 7 (in this example, the branch conveyance path 7b) that leads to the developer supply port 11 as the rotation holder 4 rotates, and the branch conveyance path In the middle of 7b, the developer is hardly biased.

As described above, in the present embodiment, the developing device 3 has a configuration in which the convex portion 10 is added to the developing container 5. However, for example, a sufficient amount of developer return by the convex portion 10 cannot be ensured. In the situation, the low-use developing device 3 with a very small number of uses may gradually develop a developer bias phenomenon as the rotating holder 4 rotates a plurality of times.
In such a situation, as the development control means 20, when a single color image forming process is continuously performed for a predetermined threshold value or more, the low-use developing device 3 having a predetermined use number or less is used. On the other hand, it is preferable to have an idle drive control unit that performs idle drive for a predetermined time.
In this manner, by adding the idle drive control unit to the development control unit 20, even if the developer is disturbed in the low-use developer 3 due to the multiple rotations of the rotation holder 4, the low It is possible to level the developer in the low usage developer 3 by driving the usage developer 3 idle.

Hereinafter, the present invention will be described in more detail based on embodiments shown in the accompanying drawings.
Embodiment 1
-Overall configuration of image forming apparatus-
FIG. 3 shows Embodiment 1 of an image forming apparatus to which the present invention is applied.
In the figure, an image forming apparatus includes an image carrier 30 such as a photoconductor, and a rotary developing device 40 that can visualize an electrostatic latent image formed on the image carrier 30 in a single color or a full color. It is equipped with.
Here, for example, an electrophotographic method is adopted as an image forming method on the image carrier 30, and after charging the image carrier 30 with a charger (not shown), an electrostatic latent image is written by the exposure device. It is a thing. The image carrier 30 may be any one that holds an electrostatic latent image and visualizes it with the rotary developing device 40. A dielectric is used as the dielectric, and a charger, ions, etc. are used as the dielectric. The electrostatic latent image may be written by a writing device.
Further, the rotary developing device 40 has a rotatable rotation holding body 41, and a plurality of developing devices 50 (specifically, 50a to 50d) are mounted on the rotation holding body 41. Each of the developing devices 50 uses, for example, a two-component developer of four colors of black (K), yellow (Y), magenta (M), and cyan (C).
In particular, in the present embodiment, the rotary developing device 40 has a development position P ₁ as a setting position of each developing device 50 and a position facing the image holding body 30, and is approximately in the rotational direction of the rotary holding body 41. The standby positions P _{2 to} P ₄ are set every 90 degrees, and the initial standby position P ₀ where none of the developing devices 50 faces the development position P ₁ is set.

-Overall configuration of the developer-
In this embodiment, the developing unit 50, as shown in FIGS. 4 to 6, the two-component developer accommodating comprising facing the developing position P ₁ open and the respective color component toner and the carrier shown in FIG. 3 And a roll-shaped developer holder 52 is rotatably disposed at a portion facing the opening of the developer container 51, and on the back side of the developer holder 52 of the developer container 51. Is configured such that a pair of agitating and conveying members 53 and 54 are rotatably arranged along the rotation axis direction of the developer holding member 52, and a partition plate 55 is provided in the developing container 51 positioned between the agitating and conveying members 53 and 54. The developer passing ports 56 and 57 are opened near both ends of the partition plate 55, and a circulating transport path 58 through which the developer transported by the stirring transport members 53 and 54 circulates through the passing ports 56 and 57 is secured. It is what you do.
Here, the developing container 51 is formed of a synthetic resin such as ABS resin, for example, and is a substantially box-shaped container that secures a developer accommodating space and is open on the side and the upper side facing the image carrier 30. A main body 51a and an upper lid 51b for closing the upper opening of the container main body 51a are provided.
The developer holder 52 is a fixed non-magnetic cylinder 52a having a magnetic pole member 52b in which an appropriate number of magnetic poles are arranged. The developer holder 52 includes a developing area. Usually, a layer thickness regulating member 59 for regulating the layer thickness of the developer conveyed to is provided.
Further, for example, a pair of stirring and conveying members 53 and 54 in which spiral blade members 61 and 62 are provided around the rotation shaft 60 is used, and the spiral blade members 61 and 62 of the stirring and conveying members 53 and 54 are used. 62 is formed so that the developer transport direction is reversed when rotated in the same direction.
Note that reverse spiral blades 63 and 64 are provided at both ends of the agitating and conveying members 53 and 54 so that the developer can be circulated and conveyed through the passage ports 56 and 57.

-Developer supply mechanism-
Further, in the present embodiment, the developing device 50 includes a developer supply mechanism 70. In this embodiment, since a developer discharge mechanism to be described later is added, toner containing a carrier is used as the replenishment developer.
The developer replenishing mechanism 70 is provided with a branch conveyance path 71 branched from the circulation conveyance path 58 on the side away from the developer holder 52 along the longitudinal direction of the circulation conveyance path 58 of the developer container 51. A stirring / conveying member 72 is rotatably arranged along the path 71, and a branch port 73 between the branching / conveying path 71 and the circulation / conveying path 58 is provided on the downstream side of the developer conveying direction by the stirring / conveying member 72. It is what I did.
The agitating and conveying member 72 is provided with a spiral blade member 76 around the rotation shaft 75 in the same manner as the agitating and conveying members 53 and 54 in the circulation conveying path 58, and the helical blade member 76 stops driving. When the rotation holder 41 rotates in this state, the developer can be moved in a direction away from the branch port 73 in the branch conveyance path 71.
Furthermore, a developer supply port 74 is provided on the upstream side of the branch conveyance path 71 in the developer conveyance direction, and a supply container 80 is connected to the developer supply port 74.
As shown in FIGS. 7 to 10, the supply container 80 is detachably attached to a receiving portion 65 formed on the upper lid 51 b of the developing container 51.
In this example, the supply container 80 is divided into a storage chamber 81 in which the supply developer is stored and a recovery chamber 82 in which the excess developer in the development container 51 is recovered. A spiral spring-like conveying member (not shown) is provided, and a supply port 83 is opened in a part of the storage chamber 81 so as to face the developer supply port 74, while a recovery port is formed in a part of the recovery chamber 82. 84, and the supply port 83 and the collection port 84 are opened and closed by a shutter 85.

-Developer discharge mechanism-
In the present embodiment, the developing device 50 includes a developer discharge mechanism 90 that can discharge excess developer.
As shown in FIGS. 5, 6 (a), (b), and FIG. 10, the developer discharging mechanism 90 accommodates the stirring and conveying member 54 on the side away from the developer holding body 52 in the circulation conveying path 58. And provided on the side wall of the developing container 51 facing the passage port 56.
The developer discharge mechanism 90 has a developer discharge port 91 opened at an appropriate position on the side wall of the developer container 51, and an open / close lid 92 is rotatably provided in the developer discharge port 91. The opening / closing lid 92 assists the developer discharging operation when the developer in the circulation conveyance path 58 increases and the developer increase amount exceeds a predetermined amount. When the posture is changed, the developer is closed to prevent excessive discharge of the developer. Reference numeral 93 is a temporary collection receptacle provided in a part of the developer container 51 for temporarily collecting excess developer discharged from the developer discharge port 91, and 94 a developer collection port ( FIG. 10).
In this example, a developer supply port 74 and a developer discharge port 91 are provided in the receiving portion 65 of the developer container 51, and these are engaged with the shutter 85 on the supply container 80 side to open and close the developer container 51 side. When the supply container 80 is attached to the receiving portion 65 of the developing container 51, the shutters 85 and 95 are engaged and opened, and the supply port 83 and the recovery port 84 of the supply container 80 are opened. 51 is connected to a developer supply port 74 and a developer recovery port 94, respectively.

-Developer guide mechanism-
Furthermore, in the present embodiment, the developing device 50 includes a developer guide mechanism 100 that guides the behavior of the developer in the developer container 51 as the rotation holder 41 rotates.
<Guide convex part>
As shown in FIGS. 11 to 13, the developer guide mechanism 100 has a guide protrusion 101 formed on the inner wall of the upper lid 51 b of the developing container 51.
In this example, the guide convex portion 101 is opposed to the stirring / conveying member 54 disposed in a portion of the inner wall of the upper lid 51b of the developing container 51 that does not face the developer holding body 52 in the circulation / conveying path 58. It is provided in a convex shape and extends while being inclined in a direction opposite to the inclination direction of the blade member 62 of the stirring and conveying member 54.
Here, as shown in FIGS. 12A and 12B and FIGS. 13A and 13B, the guide convex portion 101 is formed with a concave portion 102 on the inner wall of the upper lid 51b by, for example, cutting. The part to be surrounded is projected relative to the bottom of the recess 102 by a dimension h, and does not protrude from the inner wall surface of the upper lid 51b.
When the developing device 50 is located at the development position P ₁ , the guide convex portion 101 is arranged in non-contact with the developer in the circulation conveyance path 58 and is determined in advance with respect to the rotation axis direction of the stirring conveyance member 54. It provided with a plurality at intervals p _k that is. This distance p _k is no problem with properly selected, in this example, are substantially equivalent or selected it from to be longer in the pitch p _m of the blade member 62 of the agitation conveying member 54.
Further, the guide convex portion 101 is disposed so as to be inclined at an inclination angle θ _{k with} respect to the direction of the rotation axis 60 of the stirring and conveying member 54 facing the guide convex portion 101. The inclination angle θ _k is substantially the same as the inclination angle θ _m of the blade member 62 with respect to the direction of the rotation axis 60 of the agitating and conveying member 54 at a portion facing the guide convex portion 101, and the inclination direction is opposite. Is.
Further, the guide convex portion 101 is provided over substantially the entire region of the stirring / conveying member 54 in the direction of the rotation axis 60 and extends to the vicinity of the developer discharge port 91.
<Suppression convex part>
In particular, in the present embodiment, a suppression convex portion 103 different from the guide convex portion 101 is provided at a portion corresponding to the upstream end portion in the developer transport direction by the stirring transport member 54. The restraining convex portion 103 is provided in a convex shape on the inner wall of the upper lid 51 b facing the agitating and conveying member 54, and is configured to incline in a direction opposite to the inclination direction of the guide convex portion 101. This restraining convex portion 103 is inclined by an inclination angle θ _{n with} respect to the direction of the rotation axis 60 of the stirring and conveying member 54 and is provided substantially along the inclination direction of the blade member 62 of the stirring and conveying member 54. The restraining convex portion 103 is not necessarily inclined at the inclination angle θ _n and may be formed substantially along the radial direction of the rotating shaft 60 of the stirring and conveying member 54.

-Control system-
FIG. 14 shows a control system for the rotary developing device according to this embodiment.
In the figure, reference numeral 110 denotes a control device composed of a microcomputer or the like, which performs drive control and density control of the rotary developing device 40.
Target drive control of the rotary developing device 40, developer carrier 52 of the developing device 50 to the rotary holder 41 driving motor 112 that drives through a drive transmission mechanism 111 such as a gear at the developing position P _1, stirring drive for driving the conveying members 53 and 54 driving motor 114 that drives through a drive transmission mechanism 113 such as a gear, through a drive transmission mechanism 115 such as a gear to a stirred conveying member 72 of the developing device 50 at the developing position P ₁ From a rotation detector 130 that is a motor 116 and detects an instruction signal from the operation unit 120 such as an image forming mode (monochrome black mode (BW mode), full color mode (FC mode)) or the rotation holding body 41 is rotated. Is received by the control device 110, and a predetermined drive control signal is sent to each of the drive motors 112, 114, and 116. As the rotation detector 130, an encoder for detecting the rotation operation of the rotation holder 41 is used.
Further, the density control of the rotary developing device 40 is performed by, for example, a toner in the developer from a density detector 140 (for example, using a detector that detects magnetic permeability) that can detect the toner density of the developer in the developer 50. The density is grasped, and the developer supply operation is controlled based on the density.
The density detection method is not limited to the method of directly detecting from the developer in the developing device 50. For example, an image density detection pattern is formed on the image carrier 30 as shown by a two-dot chain line in FIG. May be detected by an optical density detector 141.

-Operation of image forming device-
Next, the operation of the image forming apparatus according to the present embodiment will be described focusing on the rotary developing device.
Now, when a specific single-color job (e.g. monochromatic black job) is assumed as carried out continuously, each end of the single specific monochromatic job, the developing device 50 (e.g., the developing device 50a) from the developing position P ₁ When the next specific single-color job is moved to the initial standby position P ₀ by approximately one rotation, it moves again from the initial standby position P ₀ to the development position P ₁ to perform the specific single-color job.
Here, when the developing device 50 (for example, the developing device 50a) rotates approximately _once from the developing position P1, the developer G in the developing container 51 of the developing device 50 is rotated by the developing device 50 as shown in FIG. The behavior of moving around the agitating and conveying members 53 and 54 by the accompanying posture change is shown.
In this behavior of the developer G, for example, when attention is paid to the agitating / conveying member 54, as shown in FIG. 16, the developing device 50a has a developing position P ₁ → standby position P ₂ → standby position P ₃ → standby position P ₄ → During the period from the initial standby position P _{0 to the} development position P ₁ , the developer G tends to move in the direction opposite to the original conveyance direction along the blade member 62 of the agitation conveyance member 54. And in particular with the developing device 50 makes one rotation as shown in FIG. 17, the developer amount G _m which corresponds to one pitch p _m fraction of the blade member 62 is going to flow back.
At this time, when attention is focused on the developer guide mechanism 100, the developing device 50 (e.g., the developing device 50a) while the continue to rotate successively in the standby position _P 2 to P ₄ from the developing position _{P 1,} the guide protrusion 101 of the developing container 51 developer G continue to move to the site of the developer G is pushed back only the amount of developer G _k corresponding to the interval p _k between the guide protrusions 101 along the inclination direction of the guide protrusion 101.
In this case, _{(corresponding} to the developer back-flow amount) of one pitch p developer amount corresponding to _m minutes G _m of the blade member 62 and the developer amount G _k corresponding to the interval p _k between the guide protrusions 101 _(developing If the developer G is selected so as to be substantially the same, the developer G follows the blade member 62 of the stirring and conveying member 54 as the developing device 50 (for example, the developing device 50a) rotates. However, the developer guide mechanism 100 is pushed back in the opposite direction to the reverse flow direction. As a result, the phenomenon that the developer G in the developing device 50 flows backward along the blade member 62 of the stirring and conveying member 54 with the rotation of the developing device 50 (for example, the developing device 50a) is suppressed.

In particular, in the present embodiment, the developer guide mechanism 100 is provided corresponding to a portion of the circulation transport path 58 that does not face the developer holder 52, and therefore, as the developing device 50 rotates. Further, the backflow of the developer G at the site along the stirring and conveying member 54 is difficult to occur. For this reason, in a portion of the circulation conveyance path 58 that does not face the developer holder 52, the path area of the circulation conveyance path 58 is relatively large, and the holding force of the developer G due to the magnetic force of the developer holder 52 is high. Since it does not act, it is an area where the developer G easily moves with the rotation of the developing device 50, but the reverse flow phenomenon of the developer G hardly occurs and the bias of the developer G hardly occurs.
Therefore, even if the high-use developing device 50 (for example, the developing device 50a) used frequently for development is used in the low-use developing device 50 (for example, 50b to 50d) that has not been used for development for a long time, it is used. Even in this case, the reverse flow phenomenon of the developer G accompanying the rotation of the developing device 50 can be effectively suppressed.
In this embodiment, since the developer guide mechanism 100 is provided in the circulation conveyance path 58 connected to the developer discharge port 91, the developer G near the developer discharge port 91 is rotated with the rotation of the developing device 50. Backflow is less likely to occur. For this reason, as the developer 50 rotates, the developer G in the developer 50 flows backward, so that the situation where the excess developer G is discharged from the developer discharge port 91 is effectively suppressed.
Furthermore, in this embodiment, since the developer guide mechanism 100 includes the restraining convex portion 103 in addition to the guide convex portion 101, the guide convex portion 101 becomes the developer as the developing device 50 rotates. G acts to push back G, but at the upstream end of the circulating transport path 58 in the transport direction of the developer G by the stirring transport member 54, the developer G is placed at the end of the circulating transport path 58 due to the presence of the restraining convex portion 103. Unnecessary pressure is suppressed. For this reason, due to the presence of the developer guide mechanism 100, a situation (so-called packing) in which the developer G is densely clogged at the upstream end portion in the conveyance direction of the developer G by the stirring conveyance member 54 in the circulation conveyance path 58 is less likely to occur. .

Furthermore, in the present embodiment, the developer G holding force by the magnetic force of the developer holding body 52 acts on the portion of the circulation conveyance path 58 facing the developer holding body 52, so Even if the developer G rotates, the developer G hardly flows back along the blade member 61 of the agitating and conveying member 53. Therefore, the developer guide mechanism 100 is not provided for this portion.
Further, the branch conveyance path 71 of the developer supply mechanism 70 has a smaller path area than the circulation conveyance path 58 and is filled with the developer G for replenishment. Since the degree of backflow of the developer G accompanying the rotation of the developing device 50 is less than the part not facing the body 52, the developer guide mechanism 100 is not provided for this part in this example.
In the present embodiment, the developer guide mechanism 100 is provided in all the developing devices 50 of the rotary developing device 40. However, the present invention is not limited to this, and the developer is applied only to the low-use developing device 50. A guide mechanism 100 may be provided.
That is, the high-use developing device 50 (for example, the developing device 50a) is not subjected to development for a long time. Therefore, if the developer guide mechanism 100 is not provided, the developing device 50 is rotated. For example, the developer G flows backward along the blade member 62 of the agitating / conveying member 54. However, since the degree of backflow of the developer G is small, the agitating / conveying member 54 accompanying the developing operation by the next image forming job is performed. The developer G that has flowed back by driving is immediately leveled.

As for the operation of the developer discharging mechanism 90, as shown in FIG. 15, when the developing unit 50 is positioned at the developing position P _1, the excess developer is increased, the opening-closing lid 92 (see FIG. 6) is opened The toner is temporarily collected in the temporary collection receptacle 93 through the developer discharge port 91.
In this state, when the developing device 50 rotates approximately once, the excess developer temporarily collected in the temporary collection receptacle 93 is collected in the collection chamber 82 of the replenishing container 80 via the developer collection port 94 and temporarily collected. The receptacle 93 returns to an empty state.

Embodiment 2
FIG. 18 is an explanatory diagram showing a main part of a developing device mounted on the rotary developing device used in the second embodiment.
In the figure, a developing device 50 has a configuration substantially similar to that of the first embodiment, but a developer guide mechanism 100 is different from that of the first embodiment. Components similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted here.
In the present embodiment, the developer guide mechanism 100 is provided with the guide convex portion 101 and the suppression convex portion 103 so as to face the agitating / conveying member 54 in a portion of the circulation transport path 58 that does not face the developer holding body 52. In addition, a guide convex portion 101 and a suppression convex portion 103 are provided so as to face the agitation transport member 72 of the branch transport path 71 of the developer supply mechanism 70.
Here, the guide convex portion 101 and the restraining convex portion 103 provided in the developer supply mechanism 70 take into consideration the pitch and diameter of the agitating and conveying member 72, and as shown in FIG. It may be provided on the inner wall of the upper lid 51b of the developing container 51.
According to the present embodiment, in addition to the same effects as in the first embodiment, the backflow phenomenon of the developer in the branch conveyance path 71 of the developer supply mechanism 70 can be suppressed as the developing device 50 rotates. Is possible.
In the present embodiment, the developer that mainly wants to suppress the reverse flow phenomenon of the developer in the developer replenishing mechanism 70 with the rotation of the developing device 50 is applied only to the portion corresponding to the developer replenishing mechanism 70. A guide mechanism 100 may be provided.

Embodiment 3
FIG. 20 is an explanatory diagram showing the main part of the developing device mounted on the rotary developing device used in the third embodiment.
In the figure, the developing device 50 has a configuration substantially similar to that of the first and second embodiments, but the developer guide mechanism 100 is different from those of the first and second embodiments. Components similar to those in the first and second embodiments are denoted by the same reference numerals as those in the first and second embodiments, and detailed description thereof is omitted here.
In the present embodiment, the developer guide mechanism 100 is substantially similar to the second embodiment in that the guide convexity faces the agitating and conveying member 54 in a portion of the circulating and conveying path 58 that does not face the developer holder 52. In addition to providing the guide convex portion 101 and the suppression convex portion 103 so as to face the agitation transport member 72 of the branch transport path 71 of the developer supply mechanism 70, Among them, a guide convex portion 101 and a suppression convex portion 103 are provided so as to face the agitating and conveying member 53 at a portion facing the developer holding body 52.
Here, the guide convex portion 101 and the restraining convex portion 103 provided in the portion of the circulation conveyance path 58 facing the developer holding member 52 take into consideration the pitch and diameter of the agitation conveyance member 53 and the second embodiment. In substantially the same manner, as shown in FIG. 21, it may be provided on the inner wall of the upper lid 51b of the developing container 51. In this example, the upper lid 51b has a shape inclined obliquely upward with respect to the horizontal direction so as to cover the developer holding body 52, and the developer guide mechanism 100 is provided at the inclined portion. do it.
According to this embodiment, in addition to the same effects as those of the second embodiment, as the developing device 50 rotates, the developer reversely flows in the portion of the circulation conveyance path 58 facing the developer holding body 52. It is possible to suppress the phenomenon. For this reason, the developer located at the portion facing the developer holding body 52 is not biased, and the distribution of the developer supplied to the developer holding body 52 in the axial direction of the developer holding body 52 is substantially uniform. It is possible to keep on.
In the present embodiment, as the developing device 50 rotates, a request to mainly suppress the reverse flow phenomenon of the developer in the portion of the circulation conveyance path 58 facing the developer holding body 52 is described in the above-mentioned development. The developer guide mechanism 100 may be provided corresponding to the portion facing the developer holding body 52. Furthermore, in response to a request to suppress the backflow phenomenon of the developer at a portion corresponding to the developer supply mechanism 70, the developer guide mechanism 100 may be added to the corresponding portion.

Embodiment 4
FIG. 22A is an explanatory diagram showing a main part of the developing device mounted on the rotary developing device used in the fourth embodiment.
In the figure, a developing device 50 has a configuration substantially similar to that of the first embodiment, but a developer guide mechanism 100 is different from that of the first embodiment. Components similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof is omitted here.
In the present embodiment, the developer guide mechanism 100 has a plurality of guide protrusions 105 arranged at predetermined intervals (agitating and conveying member 54) along the rotation axis direction of the agitating and conveying member 54 facing the inner wall of the upper lid 51 b of the developing container 51. Corresponding to the pitch of the blade member 62). The guide protrusion 105 is made of a flexible film material bent in a substantially L shape, and the upper bent piece 106 is fixed to the inner wall of the upper lid 51b, and the protruding piece 107 is hung down on the lower side. Then, as shown in FIGS. 22B and 22C, the protruding piece 107 has a notch 108 corresponding to the blade member 62 of the stirring and conveying member 54, for example, in a direction opposite to the inclination direction of the blade member 62. The blade is inclined and arranged in elastic contact with the blade member 62 of the stirring and conveying member 54. In addition, a suppression protrusion that extends along a direction different from the guide protrusion 105 or the radial direction of the rotation shaft 60 of the stirring / conveying member 54 at a portion corresponding to the upstream end of the developer conveying direction by the stirring / conveying member 54. (Not shown) may be provided.
According to this aspect, when the developing device 50 rotates, the developer in the developing device 50 tends to flow backward along the agitating and conveying member 54, but the guide protrusion 105 of the developer guiding mechanism 100 is moved. It works to push back the developer that is going to flow backward. If the suppression protrusion is used, clogging of the developer at the upstream end portion in the developer conveyance direction by the agitation conveyance member 54 can be effectively suppressed.
In the present embodiment, the developer guide mechanism 100 is provided in a portion of the circulation conveyance path 58 that does not face the developer holding member 52. However, as shown in the second and third embodiments, other developer guide mechanisms 100 are provided. Of course, the developer guide mechanism 100 may be provided at the site.

Embodiment 5
In this embodiment, an image quality defect inspection process associated with developer bias by the control device is added.
In the present embodiment, for example, the basic configuration of the rotary developing device 40 is substantially the same as that of the first embodiment. However, unlike the first embodiment, an image quality defect inspection process (FIG. 23).
As shown in FIG. 23, the control device 110 determines whether or not the image forming job has ended. If the image forming job has ended, whether the image forming job is in the monochrome black mode (BW mode) or not. If it is a monochrome black mode, it is checked whether the count value of the rotation speed counter is equal to or greater than a specified value m.
Here, the rotation speed counter is for counting the rotation speed of the rotary developing device 40, and the specified value m is rotated a plurality of times by the low-use developing device 50 as the rotation holder 41 rotates. After that, it is set on the assumption of a situation in which an image quality defect occurs due to the bias of the developer when it is used.
If the count value of the rotation number counter is equal to or greater than the specified value m, for example, the presence / absence of the low use developer 50 having a development drive amount of 0 is checked. In this example, it is understood that the yellow, magenta, and cyan developing devices are the low-use developing devices 50 unless the full-color mode is specified. Therefore, when the single-color black mode continues for a predetermined number of times, the low-use developing device 50 Judge that it exists.
Then, the low use developing unit 50 a predetermined time during idle driving in a state of moving the low use developing device 50 to the developing position P ₁ by controls the driving motor 112 and the drive motor 114 if an empty drive is completed At this point, the developing drive amount of the developing device 50 is cleared to zero, and then the rotation number counter is cleared to zero.
On the other hand, when the image forming job is in the full color mode, the low-use developing device 50 is used for development. Therefore, the idle driving control for the low-use developing device 50 is not necessary at the stage of the development. Use to clear the rotation counter to zero.
According to this aspect, since the developer guide mechanism (not shown) is provided, the reverse flow phenomenon of the developer in the developing device 50 accompanying the rotation of the developing device 50 can be suppressed as in the first embodiment. In a situation where the amount of developer flowing back by the agitating / conveying member 54 is larger than the amount of developer returning by the developer guide mechanism, when a specific single color job (monochromatic black job) is continuously executed, FIG. As shown in a), the developer in the circulation conveyance path 58 of the low-use developing device 50 is biased. However, since predetermined idle drive control is performed on this, as shown in FIG. Deviation of the developer in the circulation conveyance path 58 is leveled.
In this embodiment, the rotary developing device 40 is the mode shown in the first embodiment. However, the present invention is not limited to this. For example, the rotary developing device 40 is not limited to the rotary developing device 40 shown in the second to fourth embodiments. Of course, the embodiments may be combined.

DESCRIPTION OF SYMBOLS 1 ... Image holding body, 2 ... Rotary developing device, 3 (3a-3d) ... Developer, 4 ... Rotating holding body, 5 ... Developing container, 5a ... Upper cover, 6 ... Developer holding body, 7 ... Conveyance path, 7a ... circulation conveyance path, 7b ... branch conveyance path, 8 (8a to 8c) ... stirring conveyance member, 10 ... convex part, 11 ... developer supply port, 12 ... developer discharge port, 15 ... rotary shaft, 16 ... blade Member, 20 ... development control means, G ... developer, P ₀ ... initial standby position, P ₁ ... development position, P _{2 to} P ₄ ... standby position

Claims (14)

A plurality of developing units for developing an electrostatic latent image of a predetermined color component held on the image carrier with a developer of a corresponding color;
A rotation holding body that is rotatably provided in a predetermined direction and mounts each developing device so that the plurality of developing devices are arranged along the rotation direction;
The development position facing the image carrier and a standby position other than the development position are set as the stop positions of the development units, and one or a plurality of development units used in a series of image forming processes using a single color or a composite color are the development position. The developing device is driven to be developable while the developing device is stopped at the developing position, and the last developing device located at the developing position is determined in advance by image forming processing with a single color or a composite color. Development control means for controlling the rotating holder and the developing devices so as to return to the initial standby position,
Each of the developing units has a developing opening facing the image carrier, and a developing container for storing a two-component developer containing toner and carrier;
A developer holder that faces the development opening of the developer container and holds the developer to rotate and convey it;
A transport path that is provided in the developer container and transports the developer so that the developer circulates between a portion facing the developer holder and a portion not facing the developer holder;
A spiral blade member is provided around the rotation axis extending along the rotation axis direction of the developer holding member in the conveyance path, and the developer is stirred and conveyed along the conveyance path by rotating. A plurality of stirring and conveying members;
A convex portion provided in a convex shape on the inner wall of the developing container facing at least a part of the plurality of stirring and conveying members and extending in a direction opposite to the inclination direction of the blade member of the opposed stirring and conveying member. A rotary developing device characterized by that. The rotary developing device according to claim 1,
The rotary developing device, wherein the convex portion is not in contact with the developer in the transport path when the developing unit having the convex portion is located at the development position. The rotary developing device according to claim 1 or 2,
A plurality of the convex portions are provided at intervals with respect to the rotation axis direction of the stirring and conveying member. The rotary developing device according to any one of claims 1 to 3,
The above-mentioned convex part forms a concave part in the inner wall of the member which constitutes a development container, and makes the portion surrounded by the concave part project relatively with respect to the bottom of the concave part. . The rotary developing device according to any one of claims 1 to 4,
The rotary developing device, wherein the convex portion is provided in a portion of the transport path that does not face the developer holding member. The rotary developing device according to any one of claims 1 to 5,
The rotary developing device, wherein the convex portion is provided in a portion of the transport path facing the developer holder. The rotary developing device according to any one of claims 1 to 6,
The rotary developing device, wherein the convex portion is set to have a longer dimension along the rotation axis direction of the stirring and conveying member than one pitch of the blade member of the opposing stirring and conveying member. The rotary developing device according to any one of claims 1 to 7,
A portion of the transport path corresponding to the upstream end of the developer transport direction by the stirring transport member and provided in a convex shape on the inner wall of the developer container facing the stirring transport member, and the rotation shaft of the stirring transport member A rotary developing device having another convex portion that is inclined along a radial direction of the convex portion or in a direction opposite to the inclination direction of the convex portion. The rotary developing device according to any one of claims 1 to 8,
The developing device is a rotary developing device provided in a part of the developing container and having a developer replenishing port capable of replenishing a new developer containing at least toner. The rotary developing device according to any one of claims 1 to 9,
The developer is provided in a part of the developer container, and a developer replenishing port capable of replenishing a new developer containing toner and carrier,
And a developer discharge port provided in a part of the developing container and capable of discharging excess developer. The rotary developing device according to claim 10, wherein
The rotary developing device is characterized in that the convex portion is provided at a part facing the agitating / conveying member disposed in the conveying path leading to the developer discharging port and at least adjacent to the developer discharging port. . The rotary developing device according to any one of claims 9 to 11,
The rotary developing device, wherein the convex portion is provided to face an agitating / conveying member disposed in a conveying path leading to the developer supply port. An image carrier that selectively holds electrostatic latent images of a plurality of predetermined color components;
The rotary developing device according to any one of claims 1 to 12, wherein an electrostatic latent image of each color component provided opposite to the image carrier and held by the image carrier is developed with a developer of a corresponding color. When,
An image forming apparatus comprising: The image forming apparatus according to claim 13.
The development control means causes the low-use developer having a predetermined number of times of use or less to be idled for a predetermined time when image formation processing by a single color is continuously performed for a predetermined threshold or more. An image forming apparatus having an idle drive control unit.

Images