JP2023000241A - developing device - Google Patents

Abstract

To obtain a high stirring property while maintaining a conveying property even if a small amount of developer is stored.SOLUTION: A developing device has a developer container having a developing chamber that supplies developer to a developing sleeve, and a stirring chamber that forms a circulation path of the developer with the developing chamber, and a second conveying screw that is disposed in the stirring chamber and conveys the developer in a front direction F. The second conveying screw has a spiral blade in a spiral shape that has a gap part which is discontinuous and a plurality of stirring plates that are provided on the gap part. The stirring plates each have a wall surface that intersects with the axis of rotation of the second conveying screw and a notch part in a shape in which an outer peripheral part of the wall surface is partially cut off. The stirring plates are arranged in part of an area from an end of a second communication port in an aft direction R to an end of a first communication port in a front direction F. The developing device has a regulation member that faces the gap part and the second conveying screw in the aft direction R and projects from the developer container. The length in the second conveying screw conveyance direction of the regulation member is longer than the length in the second conveying screw conveyance direction of the regulation member provided on the gap part.SELECTED DRAWING: Figure 6

Description

The present invention relates to a developing device for developing an electrostatic image formed on an image carrier.

2. Description of the Related Art Conventionally, electrophotographic and electrostatic recording image forming apparatuses have been widely used as copiers, printers, facsimiles, and multifunctional machines having a plurality of these functions. In general, a developing device provided in an electrophotographic or electrostatic recording image forming apparatus includes a one-component developer containing magnetic toner as a main component, or a two-component developer containing non-magnetic toner and a magnetic carrier as main components. agent is used. In particular, in image forming apparatuses that form full-color or multi-color images by electrophotography, two-component developers are used in most of the developing apparatuses from the viewpoint of image tint.

Conventionally, in such an electrophotographic two-component developing device, various conveying members have been proposed in order to sufficiently agitate the replenished toner and developer (Patent Documents 1 to 3).

For example, Patent Literature 1 discloses a configuration in which stirring ribs are provided on a conveying member as a proposal for improving stirring performance. Japanese Patent Laid-Open No. 2002-200002 discloses a configuration in which a spiral blade of a conveying member is partially cut off as a proposal for improving the stirring performance. Patent Document 3 proposes a configuration in which a retention portion and a regulation portion are provided as a proposal for improving stirring performance.

JP 2003-270947 A JP-A-8-286480 JP 2014-191038 A

In recent years, as image forming apparatuses have become smaller, the amount of developer used has decreased. On the other hand, the speed of the main body of the image forming apparatus has been increased, and along with this, the amount of replenishment toner that is replenished per unit time is also increasing. Therefore, it has become a problem to quickly agitate the supplied toner in a small amount of developer.

In Patent Documents 1 to 3, in order to improve the stirring performance in the developing container, a structure in which a stirring rib is provided in a conveying member, a structure in which a spiral blade is partially missing, and a retention portion and a regulation portion are provided. I have a configuration. In a configuration in which a stirring rib is provided on the conveying member, a configuration in which a spiral blade is partially missing, or a configuration in which a stagnation portion and a regulation portion are provided, there is resistance in the screw conveying direction, and the developer conveying performance is lowered. end up

SUMMARY OF THE INVENTION It is an object of the present invention to provide a developing device capable of obtaining high agitation while maintaining transport performance even if the amount of developer is small.

In order to achieve the above object, a developing device according to one aspect of the present invention has the following configuration. That is, a developer carrier that carries a developer and rotates, a first chamber that supplies the developer to the developer carrier, and a second chamber that forms a developer circulation path with the first chamber. a first conveying screw disposed in the first chamber for conveying the developer in a first direction; and a second conveying screw disposed in the second chamber in a second direction opposite to the first direction. and a first communication port that separates the first chamber and the second chamber inside the developer container and transfers the developer from the second chamber to the first chamber. and a partition wall provided upstream in the second direction from the first communication port and having a second communication port for transferring the developer from the first chamber to the second chamber, wherein , the second conveying screw has a helical blade having a discontinuous gap and a plurality of stirring members provided in the gap; A regulating member protruding from the developing container facing the helical blade, wherein the length of the regulating member in the conveying direction of the second conveying screw is the length of the regulating member facing the gap portion in the conveying direction of the second conveying screw. characterized by being longer than the

According to the present invention, even if the amount of developer is small, it is possible to obtain high stirring performance while maintaining transport performance.

1 is a schematic diagram for explaining the configuration of an image forming apparatus according to a first embodiment; FIG. FIG. 2 is a cross-sectional view for explaining the configuration of a developing device according to the first embodiment; FIG. 2 is a vertical cross-sectional view for explaining the configuration of a developing device according to the first embodiment; It is explanatory drawing of the 2nd conveyance screw stirring part of 1st Embodiment. It is a figure for demonstrating the blade|wing angle of the spiral shape of 1st Embodiment. 4A and 4B are explanatory diagrams of a regulating member protruding from the developer container of the first embodiment; FIG. It is explanatory drawing of the 2nd conveyance screw stirring part of 2nd Embodiment. FIG. 11 is an explanatory diagram of a regulating member protruding from a developer container according to a third embodiment;

<First Embodiment>
A first embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.

§1. {Overall Configuration of Image Forming Apparatus}
[Image forming apparatus]
First, a schematic configuration of an image forming apparatus according to this embodiment will be described with reference to FIG. The image forming apparatus 1 of the present embodiment is an electrophotographic tandem full-color printer including four image forming units PY, PM, PC, and PK each having a photosensitive drum 3 as an image carrier. The image forming apparatus 1 forms a toner image (image) on a recording material according to an image signal from a document reading device 2 connected to the apparatus main body 10 or a host device such as a personal computer communicably connected to the apparatus main body 10 . to form. Examples of recording materials include sheet materials such as paper, plastic films, and cloth (hereinafter abbreviated as sheets). The image forming units PY, PM, PC, and PK form yellow, magenta, cyan, and black toner images, respectively.

It should be noted that the four image forming units PY, PM, PC, and PK provided in the image forming apparatus 1 have substantially the same configuration except that they have different developed colors. Therefore, here, the image forming section PY will be described as a representative, and the description of the other image forming sections will be omitted.

The image forming apparatus 1 includes a control section 12 . The control unit 12 is composed of a computer, and includes, for example, a CPU, a ROM for storing programs for controlling each unit, a RAM for temporarily storing data, and an input/output circuit for inputting/outputting signals from/to the outside. The CPU is a microprocessor that controls the overall control of the image forming apparatus 1 and is the main body of the system controller. The CPU is connected to the sheet feeding section, the image forming sections PY, PM, PC, PK, the sheet conveying section, and the like via an input/output circuit, and exchanges signals with each section and controls their operations.

[Image forming unit]
The image forming station PY has a photosensitive drum 3 , a charging roller 4 , an exposure device 5 , a developing device 6 , a primary transfer roller 7 and a cleaning blade 8 . The photosensitive drum 3 and the charging roller 4 are rotatably supported by the drum container 51 , and the charging roller 4 and the cleaning blade 8 are supported while being pressed against the photosensitive drum 3 . The photosensitive drum 3 , charging roller 4 , cleaning blade 8 , and drum container 51 constitute a drum cartridge 50 that is detachable from the apparatus main body 10 .

The photosensitive drum 3 as a rotatable image bearing member is a cylindrical (drum-type) electrophotographic photosensitive member having a photosensitive layer made of a negatively charged organic photosemiconductor. The photosensitive drum 3 has a diameter of 30 mm and a longitudinal length of 360 mm. It rotates by driving force. Since the charging roller 4 is pressed against the photosensitive drum 3 , the charging roller 4 rotates following the photosensitive drum 3 . As the exposure device 5, a laser beam scanner having a semiconductor laser for irradiating the photosensitive drum 3 charged by the charging roller 4 with a laser beam is applied.

A transfer device 20 is arranged above each of the image forming units PY, PM, PC, and PK. The transfer device 20 is configured such that an endless intermediate transfer belt 21 is stretched around a plurality of rollers and moves (rotates) in the direction of the arrow. The intermediate transfer belt 21 carries and conveys the toner image primarily transferred to the intermediate transfer belt 21 . A secondary transfer outer roller 23 is disposed at a position opposed to the secondary transfer inner roller 22 among the rollers around which the intermediate transfer belt 21 is stretched, with the intermediate transfer belt 21 interposed therebetween. onto the sheet S, forming a secondary transfer portion T2. A fixing device 30 is arranged downstream of the secondary transfer portion T2 in the sheet conveying direction. A storage container 9 for replenishing developer to the developing device 6 is arranged above the transfer device 20 .

A cassette 40 containing sheets S is arranged at the bottom of the image forming apparatus 1 . The sheet S fed from the cassette 40 is conveyed toward the registration rollers 42 by the conveying rollers 41 . Then, the leading edge of the sheet S abuts against the stopped registration roller 42 to form a loop, thereby correcting the skew of the sheet S. After that, the rotation of the registration roller 42 is started in synchronization with the toner image on the intermediate transfer belt 21, and the sheet S is conveyed to the secondary transfer portion T2.

A process of forming, for example, a four-color full-color image using the image forming apparatus 1 configured as described above will be described. First, when the image forming operation starts, the surface of the rotating photosensitive drum 3 is uniformly charged by the charging roller 4 . Next, the photosensitive drum 3 is exposed to laser light corresponding to the image signal emitted from the exposure device 5, and an electrostatic image is formed on the photosensitive drum 3 according to the image signal. The electrostatic image on the photosensitive drum 3 is developed into a visible image by toner as a developer accommodated in the developing device 6 .

The toner image formed on the photosensitive drum 3 is transferred to the intermediate transfer belt 21 at the primary transfer portion T1 (see FIG. 2) configured between the primary transfer roller 7 and the intermediate transfer belt 21. Primary transfer. At this time, a primary transfer bias is applied to the primary transfer roller 7 . Transfer residual toner remaining on the surface of the photosensitive drum 3 after the primary transfer is removed by the cleaning blade 8 .

Such an operation is sequentially performed in each of the yellow, magenta, cyan, and black image forming portions PY, PM, PC, and PK, and four color toner images are superimposed on the intermediate transfer belt 21 . After that, the sheet S housed in the cassette 40 is conveyed to the secondary transfer portion T2 in synchronization with the formation timing of the toner image. By applying a secondary transfer bias to the secondary transfer outer roller 23, the four color toner images on the intermediate transfer belt 21 are secondary transferred onto the sheet S all at once. The intermediate transfer belt cleaner 24 removes the toner remaining on the intermediate transfer belt 21 after being transferred at the secondary transfer portion T2.

The sheet S is then conveyed to the fixing device 30 . The fixing device 30 includes a fixing roller 31 and a pressure roller 32 each having a heat source such as a halogen heater. By passing the sheet S having the toner image transferred through the fixing nip portion of the fixing device 30, the sheet S is heated and pressurized. The toner on the sheet S is then melted and mixed and fixed to the sheet S as a full-color image. After that, the sheet S is discharged onto the discharge tray 11 by the discharge rollers 43 . This completes a series of image forming processes.

Note that the image forming apparatus 1 of the present embodiment can form a single-color or multi-color image, such as a single-color black image, using an image forming unit for a desired single color or some of the four colors. is also possible.

§2. {Basic configuration of developing device}
Next, a detailed configuration of the developing device 6 will be described with reference to FIGS. 2 and 3. FIG. In this embodiment, the developing device 6 is in the form of a cartridge and constitutes a developing cartridge. The developing device 6 includes a developing container 60 containing a developer containing a non-magnetic toner and a magnetic carrier, and a developing sleeve (developing sleeve) which is a cylindrical rotating body that rotates while carrying the developer in the developing container 60 . agent carrier) 70. The developing sleeve 70 is accommodated in the developing container 60 with a gap G with respect to the photosensitive drum 3 , carries the developer contained in the developing container 60 , and conveys the developer to the developing area Ar facing the photosensitive drum 3 . to develop the electrostatic latent image.

As shown in FIG. 3, the developing sleeve 70 has a central shaft 71, is supported by a sleeve bearing 72 that rotatably supports the central shaft 71 with respect to the developing container 60, and is rotationally driven in the direction of the arrow in FIG. be. In this specification, the rotation axis direction of the developing sleeve 70 is indicated as the longitudinal direction (width direction) X, the front side of the apparatus body 10 in the longitudinal direction X is indicated as the front direction F, and the back side thereof is indicated as the rear direction R.

As shown in FIG. 2 , inside the developing sleeve 70 , a magnet roller 73 as a developing magnet having a plurality of magnetic poles arranged in the circumferential direction is arranged non-rotatably with respect to the developing container 60 by a magnet support shaft 74 . ing. The interior of the developing container 60 is horizontally divided into a developing chamber (first chamber) 62 and a stirring chamber (second chamber) 63 by a partition wall 61 extending in the rotational axis direction of the developing sleeve 70 at its substantially central portion. partitioned. As a result, the developer is accommodated in the developing chamber 62 and the stirring chamber 63 separated by the partition wall 61 . The developing chamber 62 and the stirring chamber 63 form a developer circulation path. A first conveying screw 64 is arranged in the developing chamber 62 , and a second conveying screw 65 is arranged in the stirring chamber 63 . The first conveying screw 64 and the second conveying screw 65 as these agitating members are arranged substantially parallel along the rotation axis direction of the developing sleeve 70 and agitate and convey the developer in the developing container 60 while agitating and conveying the developer in the developing container 60 . circulate inside. At both ends (left and right sides in FIG. 3) of the partition wall 61 in the longitudinal direction X, there are provided a first communication port 61a and a second communication port that allow the developer to pass between the developing chamber 62 and the stirring chamber 63. 61b is provided.

Both the first conveying screw 64 and the second conveying screw 65 are screw-shaped members, each of which has a helical blade around a rotation axis. The first conveying screw 64 is arranged along the longitudinal direction X of the developing sleeve 70 at the bottom of the developing chamber 62, and the developer in the developing chamber 62 is moved in the direction of the rotation axis by rotating the rotating shaft by a driving source. The developer is supplied to the developing sleeve 70 while being stirred and conveyed along. The developer that is carried on the developing sleeve 70 and whose toner has been consumed in the developing process is collected in the developing chamber 62 . The first conveying screw 64 conveys the developer in the backward direction R, which is the first direction.

The second conveying screw 65 is arranged along the longitudinal direction X of the developing sleeve 70 at the bottom of the stirring chamber 63 , and rotates the developer in the stirring chamber 63 in the direction of the rotation axis opposite to that of the first conveying screw 64 . The toner density is made uniform by conveying while agitating along the edges. The second conveying screw 65 conveys the developer in the forward direction F, which is the second direction opposite to the backward direction R. As shown in FIG. Further, the partition wall 61 is provided with a first communication port 61a for transferring the developer from the stirring chamber 63 to the developing chamber 62, and on the upstream side in the front direction F from the first communication port 61a. and a second communication port 61b for transferring the developer. The developer is conveyed by the first conveying screw 64 and the second conveying screw 65, passes through the first communication port 61a and the second communication port 61b, and circulates inside the developer container 60. As shown in FIG.

A developer replenishing port 66 for replenishing developer containing toner in the developer container 60 is provided at the upstream end of the second transport screw 65 of the stirring chamber 63 in the developer transport direction. The developer supply port 66 is connected to the storage container 9 (see FIG. 1) via a developer supply device (not shown). Therefore, the developer for replenishment is supplied from the storage container 9 into the stirring chamber 63 through the developer replenishing device and the developer replenishing port 66 . The second conveying screw 65 agitates and conveys the developer supplied from the developer supply port 66 and the developer already in the stirring chamber 63 to uniform the toner density.

Therefore, as shown in FIG. 3, the developer in the developing chamber 62, in which the toner is consumed in the developing process and the toner density is lowered, is moved backward R It moves into the stirring chamber 63 through the first communication port 61a on the side. Then, the developer that has moved into the stirring chamber 63 is transported while being stirred with the replenished developer, and moves to the developing chamber 62 through the second communication port 61b on the forward direction F side.

As shown in FIG. 2, the developing chamber 62 of the developer container 60 has an opening 60a at a position corresponding to the developing area Ar facing the photosensitive drum 3. It is rotatably arranged so that a part of it is exposed in the direction. Such a developing sleeve 70 is rotationally driven by a drive source, can convey the developer to the developing area Ar, and supplies the developer to the photosensitive drum 3 in the developing area Ar. In this embodiment, the developing sleeve 70 is formed of a non-magnetic material such as aluminum or stainless steel in a cylindrical shape, has a diameter of 20 mm, a longitudinal length of 334 mm, and a process speed (peripheral speed) of 250 mm/sec. Rotate during development.

A developing blade 67 that regulates the amount (layer thickness) of the developer carried on the developing sleeve 70 is fixed on the upstream side of the opening 60 a in the rotational direction of the developing sleeve 70 . Developer blade 67 forms a thin layer of developer on the surface of developer sleeve 70 .

The magnet roller 73 is formed in a roller shape having a total of five magnetic poles S1, S2, S3, N1, and N2 in the circumferential direction. Such a magnet roller 73 generates a magnetic field for carrying the developer on the developing sleeve 70 and also generates a magnetic field for peeling the developer from the developing sleeve 70 in the peeling area.

As the developing sleeve 70 rotates, the developer on the developing sleeve 70 rises in the developing area Ar to form magnetic spikes. This magnetic brush contacts the photosensitive drum 3 rotating in the same direction as the developing sleeve 70 in the developing area Ar, and develops the electrostatic image on the photosensitive drum 3 as a toner image with the charged toner. In order to improve the development efficiency, that is, the rate of toner application to the latent image, a development bias voltage obtained by superimposing a DC voltage and an AC voltage is normally applied to the development sleeve 70 from a development bias power supply. The developer on the developing sleeve 70 after the toner has been supplied to the photosensitive drum 3 is collected in the developing chamber 62 as the developing sleeve 70 further rotates.

As shown in FIG. 3, the developer container 60 is provided with an inductance sensor (toner density detection means) 68 for detecting information regarding the toner density of the developer in the developer container 60 . In this embodiment, the inductance sensor 68 is provided downstream of the stirring chamber 63 in the developer transport direction.

§3. {Regarding the configuration of the present invention}
[Second conveying screw]
Next, a detailed configuration of the second conveying screw 65 will be described with reference to FIGS. 3 and 4. FIG. The second conveying screw 65 has a shaft portion 80 , a helical spiral blade (vane) 81 , and a stirring portion 90 . In this embodiment, the second conveying screw 65 is made of plastic, for example, and is formed by injection molding. In this embodiment, the spiral blade 81 is, for example, one, and has an outer diameter of 14 mm and a pitch of 30 mm. Therefore, the angle of the spiral blade 81 calculated from the outer peripheral length (43.98 mm) of the spiral blade 81 and the pitch (screw pitch) is 55.7° (see FIG. 5). Here, the second conveying screw 65 has an outer diameter of 14 mm and a pitch of 30 mm. , outer diameter and pitch are not limited to the above dimensions. Moreover, in the present embodiment, the case where the number of threads of the spiral blade 81 is one has been described, but the number is not limited to this, and the number of threads may be two or more.

The spiral blade 81 has a gap portion 82 that forms a discontinuous gap by missing a length of 30 mm corresponding to one pitch of the spiral blade 81 . In the present embodiment, the length of the gap portion 82 is 30 mm, which is equivalent to one pitch.

The stirring section 90 is provided in the gap section 82 and has a plurality of stirring plates (stirring members) 91 , 92 , 93 and 94 . In the present embodiment, four (four) stirring plates 91 to 94 are provided, but the number is not limited to this, and the number may be two or more, particularly preferably two to four.

Each of the agitating plates 91 to 94 has a plate shape that intersects the rotation axis of the second conveying screw 65 and is arranged in the gap 82 at equal intervals. In this embodiment, each of the stirring plates 91 to 94 is provided orthogonal to the rotation axis of the shaft portion 80. As shown in FIG. However, the angle at which each of the stirring plates 91 to 94 is provided with respect to the direction of the rotation axis of the second conveying screw 65 is not limited to 90°, and may be any number of degrees. It is preferable to set the angle within the following range. In this case, stirring performance can be improved.

Each of the stirring plates 91-94 has an outer diameter equal to that of the second conveying screw 65 and a thickness of 1 mm. However, the outer diameter of each of the stirring plates 91 to 94 is not limited to the outer diameter of the spiral blade 81, and may have an outer diameter equal to or smaller than the outer diameter of the spiral blade 81, for example. This prevents the outer peripheral edges of the stirring plates 91 to 94 from coming into contact with the inner peripheral surface of the stirring chamber 63 . Also, the thickness of each of the stirring plates 91 to 94 is not limited to 1 mm, and may be less than 1 mm or even greater than 1 mm. For example, when it is larger than 1 mm, depending on the ratio to the outer diameter, the shape may not be plate-like but block-like or rod-like, and such shapes can also be included.

Each of the stirring plates 91 to 94 has wall surfaces (wall portions) 91a to 94a facing the rear direction R side, and notch portions 91b to 94b having a shape obtained by cutting out a part of the outer peripheral portion of the wall surfaces 91a to 94a. have. The wall surfaces 91 a to 94 a are orthogonal to the rotational axis of the second conveying screw 65 . The cutouts 91b to 94b are substantially fan-shaped around the rotation axis of the second conveying screw 65. As shown in FIG. In this embodiment, the central angle of the substantially sectoral shape of the cutouts 91b to 94b is 90°. However, the central angle of the substantially fan-shaped notches 91b to 94b is not limited to 90°, and may be any number of degrees, but is preferably set to, for example, 180° or less.

The notches 91b to 94b of the stirring plates 91 to 94 are provided with a phase shift of 90° in the rotation direction R1 of the second conveying screw 65. As shown in FIG. Here, in the present embodiment, the state in which the notches are out of phase means that when the second conveying screw 65 is viewed from the axial direction, each of the adjacent agitating plates is in the circumferential direction about the center of rotation. It means a state in which the positions of the cutouts do not match each other.

In the present embodiment, with respect to the forward direction F, which is the direction of toner transport, the cutout portion 92b on the next downstream side of the cutout portion 91b on the most upstream side is in the direction opposite to the rotational direction R1 of the second conveying screw 65. They are arranged with a 90° phase shift. In addition, with respect to the forward direction F, which is the toner transport direction, the notch portion 93b on the next downstream side of the notch portion 92b is arranged with a 90° phase shift in the direction opposite to the rotation direction R1 of the second conveying screw 65. It is Furthermore, with respect to the forward direction F, which is the toner transport direction, the notch 94b on the next downstream side of the notch 93b is arranged with a 90° phase shift in the direction opposite to the rotation direction R1 of the second conveying screw 65. It is Thus, the notches 91b to 94b of at least one of the stirring plates 91 to 94 are positioned differently in the circumferential direction about the rotation axis of the second conveying screw 65 than the adjacent notches. . In this embodiment, the cutouts 91b to 94b of all the agitating plates 91 to 94 are provided with a phase shift of every 90° in the rotation direction R1 of the second conveying screw 65, but this is not the only option. The angle may be other than 90°, or the phase may be matched. Alternatively, for example, each of the stirring plates 91 to 94 may have a different phase shift angle.

Here, the volume ratio of the stirring plates 91 to 94 in the case of having an annular shape without the notches 91b to 94b is 100%. In this embodiment, each of the agitating plates 91 to 94 has 90° cutouts 91b to 94b, so that the volume ratio is 75% of the annular shape without the cutouts 91b to 94b. have. Further, the space occupied by the cutouts 91b to 94b has a volume ratio of 25% of the annular shape without the cutouts 91b to 94b. In the present embodiment, the case where the stirring plates 91 to 94 have a volume ratio of 75% with respect to the annular shape without the cutouts 91b to 94b has been described. It can be set to about 60 to 90%. In addition, when the volume ratio of each of the stirring plates 91 to 94 to the annular shape without the notches 91b to 94b is set to exceed 90%, or when the notches 91b to 94b are not provided In this case, the stirring performance of the developer is significantly lowered, which is not preferable. If the volume ratio of each of the stirring plates 91 to 94 to the annular shape without the cutouts 91b to 94b is set to less than 60%, the stirring performance of the developer is greatly reduced, which is preferable. No.

The stirring section 90 is arranged substantially in the center of the second conveying screw 65, as shown in FIG. However, the arrangement position of the stirring unit 90 is not limited to this, and the arrangement position of the stirring unit 90 is part of the region from the rearward R side end of the second communication port 61b to the frontward F side end of the first communication port 61a. It is sufficient if the position is opposite to . As a result, since the stirring section 90 is provided in the toner circulation path in the stirring chamber 63, the circulating toner can be effectively stirred.

In this embodiment, since the inductance sensor 68 is arranged on the front direction F side of the stirring chamber 63 , by arranging the stirring part 90 substantially in the center of the second conveying screw 65 , the inductance sensor 68 is arranged on the rearward direction R side of the inductance sensor 68 . placed in As a result, even if the toner stays on the rearward direction R side of the agitating portion 90 more than the forward direction F side, it is possible to suppress the detection accuracy of the inductance sensor 68 from being affected.

[Regulation member]
Next, a detailed configuration of the regulating member 95 will be described with reference to FIGS. 4 and 6. FIG. The regulating member 95 protrudes from the developer container 60 and is provided to face the agitating portion 90 and the spiral blade 81 on the rearward R side, which is upstream of the agitating portion 90 of the second conveying screw 65 in the toner conveying direction. In this embodiment, the length of the regulating member 95 in the longitudinal direction X is 60 mm, the length in the longitudinal direction X of 45 mm facing the spiral blade 81 and 15 mm facing the stirring section 90 . In this embodiment, the length in the longitudinal direction X is set to 45 mm facing the spiral blade 81 and 15 mm facing the stirring section 90, but the length in the longitudinal direction X is not limited to this, and the length of the regulating member 95 The length of X should be longer than the length of the longitudinal direction X provided opposite to the stirring section 90 .

The regulating member 95 has a semi-cylindrical space with a radius of 8 mm centered at 12 mm above the center of the shaft portion 80 of the second conveying screw 65, and is formed so as to surround the outer periphery of the spiral blade 81 of the second conveying screw 65. there is In this embodiment, the restricting member 95 is formed so as to have a semicylindrical space above the second conveying screw 65, but the shape of the restricting member 95 is not limited to this. It is sufficient if it protrudes from the developer container 60 without being in contact with 65 .

[Second conveying screw operation]
Next, the operation of rotating the second conveying screw 65 to convey the toner in the forward direction F will be described in detail with reference to FIGS. 3, 4 and 6. FIG. As shown in FIG. 3, the developer that has flowed into the stirring chamber 63 through the second communication port 61b or the toner that has been supplied from the developer replenishing port 66 moves forward in the stirring chamber 63 as the second conveying screw 65 rotates. Transported to F.

The developer sent to the spiral blade 81 and reaching the agitating portion 90 abuts against the wall surface 91a of the agitating plate 91 closest to the rear direction R and is dammed up, and passes through the notch 91b in the forward direction F. , abuts against the wall surface 92a of the adjacent stirring plate 92 and is dammed up. At the same time, due to the rotation of the second conveying screw 65, the developer passing through the notch 91b is agitated so as to be sheared in the circumferential direction by the notch 91b. As described above, the developer passing through the notch 91b is prevented from being conveyed by the wall surface 92a of the adjacent agitating plate 92 and stays there without being conveyed quickly. agitated so that

Similarly, the developer passing through the notch 92b is blocked by the wall surface 93a of the adjacent agitating plate 93 and agitated so as to be sheared in the circumferential direction. Further, the developer passing through the notch 93b is blocked by the wall surface 94a of the adjacent agitating plate 94 and agitated so as to be sheared in the circumferential direction.

§4. {Effect of embodiment}
The developer sent to the spiral blade 81 and reaching the agitating portion 90 abuts against the wall surfaces 91a to 94a of the conveying plate 91 and is dammed. Although it is attempted to raise the developer surface of the side spiral blade 81 to promote the deterioration of the transport performance, the developer surface is regulated by providing the regulating member 95, thereby preventing the developer surface from rising and improving the transport performance. becomes possible. In addition, although the developer tends to climb over the agitating plates 91 to 94, by providing the regulating member 95 and regulating the surface of the developer, the amount of the developer to climb over the agitating plates 91 to 94 is reduced. , actively passes the developer through the cutouts 91b to 94b, and is stirred so as to be sheared in the circumferential direction. The developer that has passed through the notch 94 b is conveyed in the forward direction F, which is the toner conveying direction, in the stirring chamber 63 by the rotation of the second conveying screw 65 and reaches the inductance sensor 68 . As a result, stirring performance can be significantly improved.

Therefore, in order to solve the problem of maintaining the transport performance of a small amount of developer and efficiently agitating the replenished toner, a regulating member 95 is provided opposite the spiral blade 81 upstream in the toner transport direction from the transport plate 91 in the rear direction R side. By improving the conveying performance of the conveying plate 91, the conveying performance is maintained by preventing the deterioration of the conveying performance of the conveying plate 91, and the notches 91b to 94b provided in the stirring plates 91 to 94 stir the developer. You can solve the problem by doing

<Second embodiment>
A second embodiment of the invention will now be described in detail with reference to FIG. This embodiment differs from the first embodiment in that each of the stirring plates 91 to 94 has a cross shape centered on the rotation axis of the second conveying screw 65 . However, since other configurations are the same as those of the first embodiment, the same reference numerals are used and detailed description thereof is omitted.

In the present embodiment, as shown in FIG. 7, each of the stirring plates 91 to 94 has wall surfaces (wall portions) 91a to 94a facing the rear direction R side and part of the outer peripheral portion of the wall surfaces 91a to 94a. It has shaped notches 91b to 94b. The wall surfaces 91 a to 94 a are orthogonal to the rotational axis of the second conveying screw 65 . Each of the stirring plates 91 to 94 has a substantially cross shape when viewed from the cross-sectional direction, protrudes radially from the rotating shaft, and has four blades provided every 90° in the rotating direction R1. . Notches 91b to 94b are formed between the blades of the stirring plates 91 to 94, respectively.

Each stirring plate 91 to 94 has a height equal to the outer diameter of the second conveying screw 65 and a thickness of 1 mm. The agitating plates 91 to 94 are evenly distributed to four locations in the axial direction of the second conveying screw 65 within the gap 82 having a length of 30 mm in the conveying direction. The agitating plates 91 to 94 are provided so as to match the rotation direction R1 of the second conveying screw 65 without shifting the phases of the notches 91b to 94b. In the present embodiment, the phases of the cutouts 91b to 94b are matched without being shifted in the conveying direction, but the present invention is not limited to this. may

Here, the volume ratio of the stirring plates 91 to 94 in the case of having an annular shape without the notches 91b to 94b is 100%. In this embodiment, each of the stirring plates 91 to 94 has four cutouts 91b to 94b, and the volume is 57.9% of the annular shape without the cutouts 91b to 94b. have a ratio. Also in this embodiment, as in the first embodiment, each of the stirring plates 91 to 94 is set to, for example, about 60 to 90% of the annular shape that does not have the notches 91b to 94b. may Further, the number of blades (that is, the number of notches) in each of the stirring plates 91 to 94 is not limited to 4, and can be set to 2 to 6, for example. Furthermore, the arrangement of the blades on each of the stirring plates 91 to 94 is not limited to equal intervals, and can be set at appropriate intervals.

<Third Embodiment>
A third embodiment of the present invention will now be described in detail with reference to FIG. In this embodiment, the shape of the regulating member 95 projecting from the developer container 60 is referred to. Other configurations are the same as those of the first and second embodiments, so the reference numerals are the same and detailed description thereof is omitted.

In this embodiment, as shown in FIG. 8, a part of the regulating member 95 is located closer to the rear direction R side, which is upstream in the toner transport direction, from the second transport screw 65 than to the front direction F side, which is downstream in the toner transport direction. It is configured in a distant position.

Depending on the internal configuration of the image forming apparatus 1, the developer may come into contact with the rearward R side end portion of the regulating member 95, which is upstream in the toner conveying direction, and may be dammed up, impairing the conveying performance. Therefore, the opening area of the rearward R side end portion of the regulation member 95, which is upstream in the toner conveying direction, should be widened to prevent the developer from coming into contact with the rearward R side end portion of the regulation member 95, which is upstream in the toner conveying direction. , the conveying performance can be improved.

In the present embodiment, the angle formed by the second conveying screw 65 and a portion of the second conveying screw 65 of the regulating member 95 facing the spiral blade 81 on the rearward R side, which is upstream in the toner conveying direction of the stirring portion 90, is 9.5. Although it is set to 55°, it is not limited to this. It's okay if there are some places.

6 developing device 60 developing container 61 partition wall 61a first communication port 61b second communication port 62 developing chamber (first chamber)
63 Stirring Chamber (Second Chamber)
64 first conveying screw 65 second conveying screw 68 inductance sensor (toner density detection means)
70 development sleeve (developer carrier)
81 Spiral Feather (Feather)
82 Gap 91, 92, 93, 94 Stirring plate (stirring member)
91a, 92a, 93a, 94a Wall surface (wall portion)
91b, 92b, 93b, 94b Notch 95 Regulating member F Forward direction (second direction)
R backward direction (first direction)

Claims (16)

a developer carrier rotating while carrying the developer;
a developer container having a first chamber for supplying the developer to the developer carrier and a second chamber for forming a circulation path of the developer together with the first chamber;
a first conveying screw disposed in the first chamber for conveying the developer in a first direction;
a second conveying screw disposed in the second chamber for conveying the developer in a second direction opposite to the first direction;
a first communication port that separates the first chamber and the second chamber inside the developer container and transfers the developer from the second chamber to the first chamber; and a second direction from the first communication port. a partition wall provided on the upstream side of the developing device and having a second communication port for transferring the developer from the first chamber to the second chamber,
The second conveying screw has a helical blade having a discontinuous gap and a plurality of stirring members provided in the gap,
a regulating member protruding from the developer container facing the gap portion and the helical blade upstream in the conveying direction of the second conveying screw;
The developing device, wherein the length of the regulating member in the conveying direction of the second conveying screw is longer than the length of the regulating member facing the gap portion in the conveying direction of the second conveying screw. 2. The stirring member according to claim 1, wherein the stirring member has a wall portion that intersects the rotation axis of the second conveying screw, and a notch portion formed by cutting out a part of the outer peripheral portion of the wall portion. Developing apparatus as described. The plurality of stirring members are arranged in part of a region from an upstream end of the second communication port in the second direction to a downstream end of the first communication port in the second direction. 3. The developing device according to claim 1, wherein: The cutout portion of at least one of the stirring members is positioned differently in the circumferential direction about the rotation axis of the second conveying screw than the cutout portions of adjacent stirring members. 4. The developing device according to any one of claims 1 to 3, characterized by: The second chamber is provided with toner concentration detection means for detecting information about the toner concentration of the developer in the developing container, and the plurality of agitating members are located upstream in the second direction from a position facing the toner concentration detection means. 5. The developing device according to any one of claims 1 to 4, wherein the developing device is arranged in a 2. The stirring member has an outer diameter equal to or smaller than the outer diameter of the blade, and the notch is fan-shaped around the rotation axis of the second conveying screw. 6. The developing device according to any one of items 1 to 5. 7. The developing device according to claim 6, wherein the notch has a central angle of 180[deg.] or less. 6. The developing device according to any one of claims 1 to 5, wherein the stirring member has a cross shape centered on the rotation axis of the second conveying screw. 9. The developing device according to claim 1, wherein the wall portion of the stirring member is perpendicular to the rotation axis of the second conveying screw. 10. The developing device according to claim 1, wherein the gap has a length of one pitch of the blades. 11. The developing device according to any one of claims 1 to 10, wherein the number of said plurality of stirring members is two. 12. The developing device according to any one of claims 1 to 11, wherein the plurality of stirring members is three in number. 13. The developing device according to any one of claims 1 to 12, wherein the plurality of stirring members is four in number. a regulating member protruding from the developer container facing the stirring member and the helical blade upstream in the conveying direction of the second conveying screw;
2. A length of the second conveying screw conveying direction length of the regulating member facing the helical blade is equal to or greater than a length of the second conveying screw conveying direction length of the regulating member facing the stirring member. 14. The developing device according to any one of items 1 to 13. The distance between the upstream regulating member in the conveying direction of the second conveying screw and the second conveying screw is partly shorter than the distance between the regulating member downstream in the conveying direction of the second conveying screw and the second conveying screw. 15. The development device according to any one of claims 1-14. 16. The developing device according to any one of claims 1 to 15, wherein the regulating member is arranged at a plurality of locations.

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