JP2010078669A - Developing device, process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that improves dispersibility of supplied toner, suppresses toner agglomeration in a toner supply spiral area, and prevents occurrence of abnormal image due to toner agglomeration during the continuous or long use of it. <P>SOLUTION: The developing device 5Y includes: developing containers 75Y and 76Y storing carrier and toner; a toner supply port 58Y formed in one end of each of the developing containers 75Y and 76Y; and an agitating conveyance spiral vane 55Y projecting spirally along a rotating shaft extending lengthwise in each of the developing containers 75Y and 76Y, and used for conveying developer while agitating it. A toner supply spiral vane is provided on the toner supply port side and on a line extended from the rotating shaft with the agitating conveyance spiral vane projecting. After a developing operation or at a predetermined time interval, developer is transported to a toner supply area where the toner supply spiral vane is located, the developer containing the carrier with capacity required for the developer to reach at least the inside of the diameter of the periphery of the toner supply spiral vane is transported to the toner supply area where the toner supply spiral vane is located. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a developing device of an image forming apparatus using electrophotographic technology such as a copying machine, a facsimile machine, a printer, a process cartridge, and an image forming apparatus using the same.

One of the developers for developing the electrostatic latent image is a two-component developer. The two-component developer contains a toner and a carrier, which are used while being stirred in a developing container.
Conventionally, various configurations in which two agitating / conveying spiral shafts for agitating and conveying a developer in a predetermined direction are provided in a developing container (see, for example, Patent Documents 1 to 5).
In Patent Documents 1 to 3, two agitating / conveying spiral shafts for agitating and conveying a developer in a predetermined direction are provided in a developing container, and toner is supplied from a toner replenishing port according to toner consumption. An apparatus in which a developer (toner and carrier) is stirred and mixed is disclosed.
By the way, when toner is supplied from above the developer in the developer container, the toner having a low specific gravity is difficult to be taken into the developer, and the toner flows over the developer, and the developer and the toner cannot be sufficiently mixed. (Fig. 9).
FIG. 9 is a schematic diagram illustrating toner supply from above the developer. In the developing device 5Y, the toner is supplied from the toner replenishing port 58Y onto the developer filling the stirring and conveying spiral 55Yb. In this case, if the developer and the supplied toner cannot be mixed sufficiently, uneven density of the image due to insufficient mixing of the developer toner and the carrier, or background staining of the image due to insufficient charging of the toner may occur. There is a risk.
In Patent Documents 4 and 5, a toner supply spiral shaft for supplying toner supplied into the developing container is provided on the same axis as the stirring and transporting spiral shaft, and the stirring and transporting shaft is disposed on the stirring and transporting path. An apparatus for supplying supply toner from an axial direction to a spiral is disclosed.
FIG. 10 is a schematic diagram for explaining the supply of toner from the axial direction to the stirring and conveying spiral. In the developing device 5Y, the toner is supplied not to the developer filling the stirring and conveying spiral 55Yb but to the toner supplying spiral shaft provided below the toner supply port 58Y.
JP-A-2005-24665 JP 2007-271863 A JP 2004-77554 A JP 2002-148915 A JP 2007-94161 A

However, in the developing devices having the configurations of Patent Documents 4 and 5, an immobile toner layer is generated between the spiral outer periphery and the lower case. FIG. 11 is a schematic diagram for explaining the immobile toner layer generated in the toner supply spiral shaft. As shown in FIG. 11, the toner supplied from the toner supply port 58Y directly adheres to the surface of the spiral (screw) 55Yb or does not move between the outer periphery of the spiral and the lower case. The toner layer is generated.
When the temperature in the image forming apparatus and the developing apparatus rises due to continuous printing or the like, the toner directly attached to the spiral surface or the toner in the immobile toner layer between the outer periphery of the spiral and the lower case may form an aggregate. is there.
The agglomerate is taken into the developer due to the operation of the developing device, the detaching operation of the developing device for maintenance, etc., but if the aggregate is not sufficiently decomposed and supplied to the developing roller, black spots An abnormal image such as a white spot due to a poor adhesion with a transfer body due to an aggregate occurs. In addition, when the aggregate is sandwiched between the doctor blade and the developing roller, the developer is prevented from passing therethrough, and an image such as a white stripe may be generated.
In view of the above, the object of the present invention is to improve the dispersibility of the supplied toner and suppress the generation of toner agglomerates at the toner replenishing spiral portion, during continuous use and for a long period of time. Another object of the present invention is to provide a developing device, a process cartridge, and an image forming apparatus using the process cartridge, which prevent the occurrence of abnormal images due to toner aggregates.

In order to solve the above-mentioned problems, the invention according to claim 1 is a developer container in which a developer containing at least a carrier and a toner is accommodated and a developer conveyance path for conveying the developer is formed in a longitudinal direction. A toner replenishing port formed on one end side of the developing container and supplying toner into the developing container, a rotating shaft extending in the longitudinal direction in the developing container, and a spiral projecting along the rotating shaft, In the developing device in which the agitating / conveying spiral blade that conveys the developer while agitating is disposed, the toner is supplied to the toner replenishing port side on the extension of the rotating shaft over which the agitating / conveying spiral blade is overhanging A spiral blade for the toner supply is provided, and at the end of the developing operation or at a predetermined interval, at least the toner supply is provided at the toner supply site where the spiral blade for toner supply exists. And wherein the developing device for advection a developer containing the carrier of the capacity to reach the outer peripheral diameter of the use spiral blade.
According to a third aspect of the present invention, the rotation of the toner supply spiral blade opposite to that during the developing operation is performed immediately before the standby mode such as the energy saving or low power mode of the image forming apparatus main body. 2. A developing device according to item 2.
According to a fourth aspect of the present invention, there is provided the developing device according to the first aspect, wherein the toner supply spiral blade is provided with a communication portion that communicates in the thickness direction of the blade.

According to a fifth aspect of the present invention, there is provided the developing device according to the first aspect, wherein the toner supply spiral blade is provided with a plurality of notches along an outer peripheral portion.
According to a sixth aspect of the present invention, the outer periphery of the toner supply spiral blade is in contact with a lower case in which the toner supply spiral blade is disposed, and is rotated softly and integrally with the toner supply spiral blade. The developing device according to claim 1, wherein an elastic member is provided.
According to a seventh aspect of the invention, the developing device according to any one of the first to third aspects and an image carrier on which a toner image is formed by the developing device are at least integrally incorporated. A process cartridge is detachably attached to the image forming apparatus main body.
According to an eighth aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier that carries an electrostatic latent image; and a developing device that develops the electrostatic latent image on the image carrier with a developer. An image forming apparatus comprising the developing device according to any one of Items 1 to 3.

  According to the present invention, it is possible to suppress the generation of toner aggregates at the toner replenishment spiral portion, and to prevent the occurrence of abnormal images due to toner aggregates during continuous use and for a long period of time.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, an electrophotographic printer (hereinafter simply referred to as a printer) will be described as an example of an embodiment of an image forming apparatus to which the present invention is applied. The image forming unit will be described as a process cartridge.
FIG. 1 is a schematic diagram showing the configuration of an electrophotographic printer. FIG. 2 is a schematic view showing a process cartridge for generating a Y toner image. First, the basic configuration of the printer will be described.
1 and 2, the printer 100 includes four process cartridges 6Y, 6M, 6C, for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). It has 6K. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached.
Taking a process cartridge 6Y for generating a Y toner image as an example, as shown in FIG. 2, the process cartridge 6Y includes a drum-shaped photosensitive member 1Y, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device. A device 4Y, a developing device 5Y, and the like are provided. The process cartridge 6Y can be attached to and detached from the main body of the printer 100 so that consumable parts can be replaced at a time.

The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that is rotated clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry an electrostatic latent image for Y. The Y electrostatic latent image is developed into a Y toner image by the developing device 5Y using Y toner.
This Y toner image is intermediately transferred onto the intermediate transfer belt 8. The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process. Further, the static eliminator neutralizes residual charges on the photoreceptor 1Y after cleaning. By this charge removal, the surface of the photoreceptor 1Y is initialized and prepared for the next image formation.
In the other process cartridges 6M, 6C, and 6K, M, C, and K toner images are similarly formed on the photoreceptors 1M, 1C, and 1K, and are intermediately transferred onto the intermediate transfer belt 8.
In FIG. 1, the exposure device 7 is disposed below the process cartridges 6Y, 6M, 6C, and 6K. The exposure device 7 serving as a latent image forming unit irradiates the respective photosensitive members in the process cartridges 6Y, 6M, 6C, and 6K with a laser beam L emitted based on the image information to perform exposure.
By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photoconductor with a laser beam (L) emitted from a light source through a plurality of optical lenses and mirrors while scanning with a polygon mirror rotated by a motor.

On the lower side of the exposure apparatus 7 in the figure, a sheet feeding means having a transfer sheet accommodating cassette 26, a sheet feeding roller 27 incorporated therein, a pair of registration rollers 28, and the like are disposed.
The transfer paper storage cassette 26 stores a plurality of transfer papers P, which are recording media, and a paper feed roller 27 is in contact with the uppermost transfer paper P.
When the paper feeding roller 27 is rotated counterclockwise in the drawing by a driving means (not shown), the uppermost transfer paper P is fed toward the rollers of the registration roller pair 28. The registration roller pair 28 rotationally drives both rollers to sandwich the transfer paper P, but temporarily stops rotating immediately after the sandwiching. Then, the transfer paper P is sent out toward a later-described secondary transfer nip at an appropriate timing.
In the sheet feeding unit having such a configuration, a conveying unit is configured by a combination of the sheet feeding roller 27 and the registration roller pair 28 which is a timing roller pair. This conveying means conveys a transfer sheet P from a paper storage cassette 26 which is a storage means to a secondary transfer nip described later.
Above the process cartridges 6Y, 6M, 6C, and 6K in the figure, an intermediate transfer unit 15 that moves the intermediate transfer belt 8 that is an intermediate transfer member endlessly while stretching is disposed. In addition to the intermediate transfer belt 8, the intermediate transfer unit 15 includes four primary transfer bias rollers 9Y, 9M, 9C, and 9K, a cleaning device 10, and the like.

A secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14 and the like are also provided. The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched around these three rollers.
The primary transfer bias rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 that is moved endlessly in this manner from the photoreceptors 1Y, 1M, 1C, and 1K to form primary transfer nips, respectively. Yes.
These primary transfer bias rollers 9Y, 9M, 9C, and 9K are of a system that applies a transfer bias having a polarity opposite to that of toner (for example, plus) to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All the rollers except the primary transfer bias rollers 9Y, 9M, 9C, and 9K are electrically grounded.
The intermediate transfer belt 8 passes through the primary transfer nips for Y, M, C, and K sequentially along with the endless movement thereof, and the Y, M, and Y on the photoreceptors 1Y, 1M, 1C, and 1K are sequentially transferred. The C and K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

The secondary transfer backup roller 12 described above forms a secondary transfer nip with the intermediate transfer belt 8 sandwiched between the secondary transfer backup roller 19 and the secondary transfer roller 19. The four-color toner image formed on the intermediate transfer belt 8 is transferred to the transfer paper P at the secondary transfer nip.
Untransferred toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the cleaning device 10.
In the secondary transfer nip, the transfer paper P is sandwiched between the intermediate transfer belt 8 whose surface moves in the forward direction and the secondary transfer roller 19 and conveyed in the opposite direction to the registration roller pair 28 side. The On the transfer paper P sent out from the secondary transfer nip, the four-color toner image transferred to the surface is fixed by heat and pressure when passing between the rollers of the fixing device 20.
Thereafter, the transfer paper P is discharged out of the apparatus through a pair of paper discharge rollers 29. A stack unit 30 is formed on the upper surface of the printer main body, and the transfer sheets P discharged to the outside by the discharge roller pair 29 are sequentially stacked on the stack unit 30. A bottle container 31 is provided on the lower side of the stack unit 30 to store toner bottles 32Y, 32M, 32C, and 32K for each color.

Next, the configuration of the developing device 5Y in the process cartridge 6Y will be described mainly with reference to FIG. The developing device 5Y includes a developing unit 51Y as a developer carrying member having a magnetic field generating means therein and carrying a two-component developer containing magnetic particles and toner on the surface thereof, and is carried on the developing roller 51Y. And a doctor blade 52Y as a developer regulating member that regulates the layer thickness of the developer conveyed.
Here, the place where the developing roller 51Y is accommodated is a first chamber 53Y. Further, a place for storing the developer is a second chamber 54Y, and in this second chamber 54Y, a toner conveying screw (conveying body) 55Y (first conveying screw 55Ya, second conveying material) for agitating and conveying the toner is provided. A screw 55Yb), a toner supply port 58Y for taking the toner into the second chamber 54Y, a partition wall 59Y between the first chamber 53Y and the second chamber 54Y, and the first chamber 53Y and the second chamber. And a communication port 60Y with 54Y.
Above the toner supply port 58Y, a shutter 71Y for closing the toner supply port 58Y and a toner supply port case 72Y provided to hold the shutter 71Y and cover the toner supply port 58Y are provided.
Here, reference numeral 56Y denotes a density detection sensor for detecting the toner density of the developer. When the density detection sensor 56Y detects that the toner density is insufficient in the second chamber 54Y, a replenishment signal from the control unit 57Y. The drive motor 41Y rotates and the toner bottle 32Y (FIG. 1) rotates to replenish the toner.
Further, the entire developing device 5Y is formed of a first member 75Y (upper case) including the inner wall of the first chamber 53Y and a second member 76Y (lower case) including the inner wall of the second chamber 54Y. .

FIG. 3 is a partial schematic view showing the first embodiment of the second transport screw according to the present invention. FIG. 4 is a partial schematic view showing a modification of the second conveying screw of the first embodiment of FIG.
Next, the main part of the present invention will be described with reference to FIGS. In order to make the positional relationship between FIG. 2 and the first and second transport screws the same, FIGS. 3 and 4 consider that these views must be viewed from the back and from the opposite end. Here, description will be made based on FIGS. 3 and 4.
As shown in FIG. 2, development including an upper case 75Y and a lower case 76Y in which a developer containing at least a carrier and toner is accommodated and a developer conveyance path through which the developer is conveyed is formed in the longitudinal direction. In the container, a toner replenishing port 58Y formed on one end side of the developing container and supplying toner into the developing container, a rotating shaft 55Y2 extending in the longitudinal direction in the developing container, and a spiral along the rotating shaft 55Y2 And a second conveying screw (agitating and conveying spiral blade) 55Yb that conveys the developer while stirring.

As shown in FIG. 3A, the rotary shaft 55Y2 provided with the second transport screw (agitating and transporting spiral blade) 55Yb has a first communication port 62Y having no partition wall 59Y with respect to the first transport screw 55Ya. A toner supply screw part (toner supply spiral blade) 55Yc extending to the end side is formed.
A toner replenishing port 58Y that supplies toner to the developing device 5Y by a toner replenishing mechanism (for example, a mechanism described in Patent Document 1) is installed above the toner supply spiral blade (screw part) 55Yc (FIG. 3B). ).
As a result, as shown in FIG. 10, the toner supplied from the toner replenishing port 58Y is taken into the developer from the side (lower part) of the developer in the developer container and is transported through the developer transport path 55T. As a result, the supplied toner and the developer in the developing device 5Y are quickly mixed and agitated to prevent unevenness in image density due to insufficient mixing, and background contamination of the image due to insufficient charging of the toner.
However, also in the developing device of this configuration, the toner supplied from the toner supply port 58Y is applied to the surface of the spiral blade (screw portion) as shown in FIG. There is a possibility that an immovable toner layer is generated between the directly adhering toner and the outer periphery of the spiral blade and the lower case.

When the second conveying screw 55Yb stops due to the end of the developing operation, the developer in the developing device 5Y flows into the toner supply spiral blade 55Yc side by reverse rotation due to the height difference and the fluidity of the developer. The developer that has flowed in depends on the stop position of the spiral blade, but is divided by the spiral blade, so that the developer stops in the range of about 1.5 pitches of the screw.
4A, the toner supply spiral blade (screw part) 55Yc is longer in the axial direction than the first embodiment of FIG. Therefore, the toner supplied from the toner replenishing port 58Y can be smoothly taken into the region where the developer is present and stirred with the developer.
By configuring in this way, generation of toner aggregates at the toner supply spiral blade 55Yc (toner replenishment spiral portion) is suppressed, and abnormal images due to toner aggregates are generated during continuous use and for a long period of time. Can be prevented.
Due to the rotation of the second conveying screw 55Yb in the next developing operation, the developer that has flowed into the toner supply spiral blade 55Yc side moves in the direction of arrow D in FIG. 4B. At this time, in the area where the developer exists, the toner adhering to the surface of the toner supply spiral blade 55Yc is taken into the developer, and the surface of the toner supply spiral blade 55Yc is cleaned.

FIG. 5 is a partial cross-sectional view of the spiral blade for explaining the force that the developer acts on the outside of the spiral blade. Further, as shown in FIG. 5, in the region where the developer is present, due to the rotation of the second conveying screw 55Yb and, for example, the gradient of the spiral blade by resin molding, the developer is as indicated by the arrow G in the figure. Receives external force.
Therefore, the developer can be exchanged between the toner supply spiral blade 55Yc and the lower case. The toner has a low specific gravity, and the toner cannot be sufficiently replaced outside the outer periphery of the spiral blade (screw) diameter by screw rotation.
However, when the toner supply spiral blade 55Yc is formed long (about 2 pitches or more), the developer flows into the toner supply spiral blade 55Yc due to the natural flow of the developer when the developing operation is stopped. It will be insufficient to do.

The developer advancing to the toner replenishment site where the toner supply spiral blade (screw part) 55Yc is present is opposite to the development operation of the toner supply spiral blade 55Yc performed at the end of the development operation or at a predetermined interval. It is done by rotation. Thus, the occurrence of abnormal images due to toner aggregates can be prevented without having a special configuration / mechanism.
In the developing device having such a configuration, for example, when the process control such as density adjustment is performed, the screw is reliably rotated by performing the reverse rotation of the screw for the number of pitches of the toner supply spiral blade 55Yc at a predetermined interval. The developer can be supplied to the toner supply spiral blade 55Yc, the above-described action can be obtained, and toner aggregation can be prevented.
Note that the reverse operation of the toner supply spiral blade (screw part) 55Yc is performed, for example, when the image forming apparatus does not operate for a long time and before the mode shift to the energy saving, low power mode, etc. Only the toner can be prevented from being present in the supply spiral blade 55Yc. In this way, it is possible to prevent the occurrence of aggregates due to the presence of only toner at the toner replenishment position in a state where the image forming apparatus does not operate for a long time.

FIG. 6 is a partial schematic view showing a second embodiment of the second conveying screw according to the present invention. FIG. 6A partially shows the second transport screw 55Yb of the developing device 5Y, and shows a toner supply spiral blade (screw part) 55Yc, a toner supply port 58Y, and a first communication port 62Y.
As shown in FIGS. 6B, 6C, and 6D, the toner supply spiral blade 55Yc is provided with a communication port 55Yc1 that communicates the thickness direction of the spiral blade. 6B, 6C, and 6D show a toner supply spiral blade 55Yc having a communication port 55Yc1 having a different shape and a toner supply spiral blade 55Yc having a notch 55Yc2 as a communication port. . By providing the communication port 55Yc1 or the notch 55Yc2, when the second conveying screw 55Yb is stopped due to the end of the developing operation described above, the developer in the developing device 5Y is affected by the height difference and the flowability of the developer. The amount of the developer flowing into the toner supply spiral blade 55Yc can be increased, and the distance that the developer reaches the terminal side of the toner supply spiral blade 55Yc can be increased.
As shown in FIG. 6D described above, the same effect as that of the communication port 55Yc1 can be obtained by making the cutouts 55Yc2 at several locations on the outer periphery of the toner supply spiral blade 55Yc. The toner supply spiral blade 55Yc can set a small conveying force with respect to the conveying screws 55Ya and 55Yb in the developing device 5Y. The communication port 55Yc1 and the notch 55Yc2 improve the dispersion and agitation effects of the supplied toner. An effect is also obtained.
Thus, by providing the communication port 55Yc1 or the notch 55Yc2 in the toner supply spiral blade 55Yc, the developer fluidity is utilized, and the developer is supplied to the toner replenishment position at the end of the developing operation without a special configuration / operation. Advection.

FIG. 7 is a partial schematic view showing a third embodiment of the second conveying screw according to the present invention. In the third embodiment of the second transport screw of FIG. 7A, the shaft diameter of the central shaft 55Yc3 of the toner supply spiral blade (screw portion) 55Yc formed below the toner supply port 58Y is set to the second transport screw. The diameter is smaller than the shaft diameter of the central shaft 55Yb1 of the screw 55Yb.
7B, the central axis of the toner supply spiral blade 55Yc is removed, and only the screw 55Yd having a coil shape is formed. Thereby, when the screw is stopped, the amount of the developer flowing into the toner supply spiral blade 55Yd side can be increased, and the distance that the developer reaches the end of the toner supply screw 55Yd can be increased.

FIG. 8 is a partial schematic view showing a fourth embodiment of the second transport screw according to the present invention. In FIG. 8, the soft elastic body 55Ye is placed along the outer periphery of the case at 1.5 pitches from the end side of the toner supply spiral blade (screw part) 55Yc formed below the toner supply port 58Y of the developing device 5Y. It arrange | positions so that it may contact.
As a result, the soft elastic body 55Ye disposed on the outer peripheral portion of the toner supply spiral blade comes into contact with the lower case in which the toner supply spiral blade (screw portion) 55Yc is disposed, and rotates and moves integrally with the toner supply spiral 55Yc. Therefore, the movement or replacement of the toner and developer that are immovable between the toner supply spiral blade 55Yc and the lower case is reliably performed.
In the process cartridge, the developing device 5Y according to the present invention described above and an image carrier (FIG. 2, 1Y) on which a toner image is formed by the developing device 5Y are integrally incorporated, and can be attached to and detached from the image forming apparatus main body. Installed.
As a result, it is possible to provide a process cartridge capable of obtaining a stable image having good toner stirring / conveying performance and facilitating maintenance and replacement of the image forming means. If this process cartridge is used as an image forming apparatus, an image forming apparatus that is stable over a long period of time can be provided.

1 is a schematic diagram illustrating a configuration of an electrophotographic printer. FIG. FIG. 3 is a schematic diagram illustrating a process cartridge for generating a Y toner image. It is a partial schematic diagram showing a 1st embodiment of the 2nd conveyance screw by the present invention. It is a partial schematic diagram showing a modification of the second conveying screw of the first embodiment of FIG. It is a fragmentary sectional view of a spiral blade explaining the force which a developer acts on the outside of a spiral blade. It is a partial schematic diagram showing a 2nd embodiment of the 2nd conveyance screw by the present invention. It is a partial schematic diagram showing a 3rd embodiment of the 2nd conveyance screw by the present invention. It is a partial schematic diagram showing a 4th embodiment of the 2nd conveyance screw by the present invention. FIG. 3 is a schematic diagram illustrating toner supply from above a developer. It is the schematic explaining supply of the supply toner from an axial direction with respect to the spiral for stirring conveyance. FIG. 6 is a schematic diagram illustrating a stationary toner layer generated in a toner supply spiral shaft.

Explanation of symbols

  1Y image carrier (photosensitive member), 5Y developing device, 6Y process cartridge, 55T developer conveying path, 55Y2 rotation shaft, 55Ya first stirring and conveying spiral blade (screw part), 55Yb second stirring and conveying spiral blade (screw) Part), 55Yc Toner supply spiral blade, 55Yb1 Second agitating / conveying spiral blade rotation shaft, 55Yc1 communicating portion (communication port), 55Yc2 cutout, 55Yc3 Spiral shaft (rotating shaft) of toner supply spiral blade, 55Yd coil Screw, 55Ye soft elastic body, 58Y toner supply port, 59Y partition wall, 62Y first communication port, 75Y developer container (upper case), 76Y developer container (lower case), 100 image forming apparatus (printer)

Claims (8)

A developer container in which a developer containing at least a carrier and toner is accommodated and a developer conveyance path for conveying the developer is formed in a longitudinal direction; and a developer container formed on one end side of the developer container and containing toner in the developer container A toner replenishing port to be supplied to the developer container, a rotating shaft extending in the longitudinal direction in the developing container, and a spiral blade for agitating and conveying that projects spirally along the rotating shaft and conveys the developer while stirring. In the developing device,
A toner supply spiral blade is provided on the toner supply port side on the extension of the rotating shaft over which the stirring and conveying spiral blade extends, and the toner supply spiral blade is present at the end of the developing operation or at a predetermined interval. A developing device characterized in that a developer containing the carrier having a capacity reaching at least the outer diameter of the toner supply spiral blade is transferred to a toner replenishing portion.   The developing device according to claim 1, wherein the advancing of the developer is caused by a reverse rotation with respect to the end of the developing operation or the developing operation of the toner supply spiral blade performed at a predetermined interval.   3. The developing device according to claim 2, wherein the rotation of the spiral blade for supplying toner opposite to that during the developing operation is performed immediately before shifting to a standby mode such as energy saving or low power mode of the image forming apparatus main body.   The developing device according to claim 1, wherein the toner supply spiral blade is provided with a communication portion that communicates in a thickness direction of the blade.   2. The developing device according to claim 1, wherein the toner supply spiral blade is provided with a plurality of notches along an outer peripheral portion.   A soft elastic member that contacts with a lower case in which the toner supply spiral blade is disposed and rotates integrally with the toner supply spiral blade is provided on an outer peripheral portion of the toner supply spiral blade. Item 2. The developing device according to Item 1.   The developing device according to any one of claims 1 to 3 and an image carrier on which a toner image is formed by the developing device are at least integrally incorporated and detachably attached to the image forming apparatus main body. A process cartridge characterized by that.   4. The image forming apparatus according to claim 1, comprising: an image carrier that carries an electrostatic latent image; and a developing device that develops the electrostatic latent image on the image carrier with a developer. 5. An image forming apparatus comprising a developing device.

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