JP2004206088A - Development device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development device that discharges developer in adequate response to an increase in excessive developer while gradually and automatically replacing developer, thereby improving maintainability, and increases an amount of developer that can be stored in a developer container despite of the structure in which the developer is gradually and automatically replaced. <P>SOLUTION: The development device includes: a development container 2 for storing developer containing toner and carrier; a conveying member 2b that conveys the developer in the development container 2; a discharge port 2d which is made in the development container 2 and through which excessive developer involved in the developer supply is discharged. In the development device, the ability of the conveying member 2b to convey the developer is greater in an area of the vicinity C of the discharging opening 2d than in an area of the downstream side D2 from the opening 2D in the direction in which the developer is conveyed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a developing device that develops an electrostatic image formed by using an electrophotographic method or an electrostatic recording method, and particularly relates to a developing device used for a copying machine, a printer, a facsimile, and the like.

  In a conventional image forming apparatus, in particular, in an electrophotographic image forming apparatus for forming a chromatic image, a two-component developing method in which a non-magnetic toner and a magnetic carrier are mixed and used as a developer is widely used. .

  The two-component development method has advantages over other currently proposed development methods, such as stability of image quality and durability of the apparatus, but also deterioration of the developer due to long-term durability, especially deterioration of the carrier. Therefore, it is necessary to perform an operation of replacing the developer with the long-term use of the image forming apparatus.

  On the other hand, in the recent full-color copying machines / printers, the following techniques have been introduced as a method for maintaining high image quality without replacing the developer in order to reduce running costs.

  For example, according to Japanese Patent Application Laid-Open Publication No. H11-163, "In a developing apparatus for an electrophotographic copying machine, comprising: a stirring unit for stirring a carrier and a toner; and a developing roll for supplying a developer stirred by the stirring unit to a photoconductor. A carrier replenishing device and a toner replenishing device are separately or integrally provided above the means, and a developer overflow portion is provided on a side wall of the developing device housing. The developer can be discharged from the overflowing portion, and the characteristics of the developer in the developing device housing can be kept constant. As a result, the image quality of the copy can be kept constant. " "Aged developer in the developing device housing is automatically discharged sequentially from the developer overflowing portion. Remove the old developer from the housing of the device, refill it with new developer, and then re-attach the developing device, eliminating the need for troublesome developer replacement work, and also prevent the developer from scattering. It is hygienic. "

  That is, by gradually replacing the deteriorated developer (carrier) with a new one, the apparent progress of deterioration of the carrier is stopped, and the characteristics of the entire developer are stabilized. As a result, the operation of replacing the developer is not required, and the maintainability is improved.

  However, in recent full-color copiers / printers, the particle size of the toner and carrier in the developer has been reduced in order to achieve high image quality. The change in the tribo of the developer with respect to the change in the amount becomes large. Accordingly, the change in the bulk density of the developer in the developing device also increases. Specifically, as the amount of water decreases, the tribo increases, and the bulk density decreases. Conversely, when the water content increases, the tribo becomes lower and the bulk density becomes higher.

  If the developer amount is kept constant in this state, the bulk density decreases and the developer surface rises, or the bulk density increases and the developer surface lowers.

  In the prior art, as described above, a developer overflow portion, that is, a developer discharge port is provided on the side wall of the developing device, and the developer is discharged by overflow to maintain a constant developer surface.

  However, if the developer surface is not stabilized due to the change in the bulk density of the developer as described above, the discharge of the developer is not properly performed, and the balance between the amount of the supplied developer and the amount of the discharged developer is poor. That is, the developer amount in the developing device gradually increases, and the developer level rises.

Therefore, when the developer is discharged from the developer discharge port, if the developer surface in a place other than the discharge port becomes too high, the stirring of the replenishment toner or the change in the bulk density of the developer described above may cause the developer to fail. If the amount is excessively increased, the torque is over, and there may be a problem that high image quality cannot be maintained.
Japanese Patent Publication No. 2-15991

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developing device capable of discharging a developer with high sensitivity to an increase in surplus developer while improving maintainability by gradually and automatically changing a developer.

  It is another object of the present invention to provide a developing device capable of increasing the amount of developer contained in a developing container while adopting a configuration in which developer is automatically changed gradually.

The above object is achieved by a developing device according to the present invention. In summary, the present invention provides a developing container containing a developer including a toner and a carrier,
A conveying member for conveying the developer in the developing container,
An outlet provided in the developing container for discharging surplus developer accompanying replenishment of the developer,
In the developing device having
The developing device is characterized in that the developer carrying capacity of the carrying member is larger in a region near the outlet than in a region downstream of the outlet in the developer carrying direction.

  The developing device of the present invention includes a developing container that stores a developer containing a toner and a carrier, a conveying member that conveys the developer in the developing container, and a surplus developer that is provided in the developing container and discharges the surplus developer accompanying the replenishment of the developer. And a developing device having a discharge port, the developer carrying capacity of the conveying member is larger in the area near the discharge port than in the area downstream of the discharge port in the developer conveyance direction. In the full-color image forming apparatus of various configurations including the system, the developer can be gradually and automatically replaced, and the developer can be discharged with a high sensitivity to the increase of the surplus developer, so that the maintainability is improved, and the developer is discharged. Even if the particle size is reduced, it is possible to avoid poor stirring and torque over, and to increase the amount of the developer in the developer container while adopting the trickle structure, so that it can be used for continuous solid jobs. It is possible to maintain a high image quality in an environment.

  Hereinafter, the developing device according to the present invention will be described in more detail with reference to the drawings.

Example 1
FIG. 1 is a diagram illustrating a developing device of the present embodiment, and FIG. 5 is a diagram illustrating an example of an image forming apparatus using the developing device.

  First, the operation of the entire image forming apparatus will be described. The image forming apparatus of this embodiment has a drum-shaped electrophotographic photosensitive member (photosensitive drum) 128 as an image carrier. In FIG. 5, first, the surface of the photosensitive drum 128 charged by the charger 121 is irradiated with a laser 122. The exposure forms an electrostatic latent image on the photosensitive drum 128, and the latent image is developed by the developing device 1 to form a developer image (toner image) on the photosensitive drum 128.

  After the toner image is transferred to the recording paper 127 conveyed by the transfer belt 124 by the transfer bias by the transfer charger 123, the recording paper 127 is separated from the transfer belt 124, and is pressed / heated by the fixing device 125. Obtain a permanent image. Further, the residual toner remaining on the photosensitive drum 128 after the transfer is removed by the cleaner 126 to prepare for the next image formation.

  Next, the developing device 1 will be described in detail with reference to FIG.

  The developing device 1 contains a two-component developer containing a non-magnetic toner and a magnetic carrier, and the mixing ratio thereof is about 1: 9 by weight. This ratio should be properly adjusted in accordance with the charge amount of the toner, the particle size of the carrier, the configuration of the image forming apparatus, and the like, and does not necessarily have to follow this numerical value.

  The developing device 1 has an opening in a developing region facing the photosensitive drum 128, and a developing sleeve 3 as a developer carrier is rotatably arranged so as to be partially exposed at the opening. The developing sleeve 3 containing a fixed magnet 4 as a magnetic field generating means is made of a non-magnetic material, and rotates in the direction of the arrow in FIG. 1 during the developing operation to hold the two-component developer in the developing container 2 in layers. The sheet is transported to the developing area and supplied to the developing area facing the photosensitive drum 128 to develop the electrostatic latent image formed on the photosensitive drum 128. The developer after developing the electrostatic latent image is transported according to the rotation of the developing sleeve 3 and is collected in the developing container 2.

  The developing container 2 is partitioned by a partition 2g into a first chamber 2e, which is a developing chamber on the side closer to the developing sleeve 3, and a second chamber 2f, which is a stirring chamber. The first chamber 2e and the second chamber 2f are respectively provided. A first transport member, a first transport screw 2a and a second transport screw 2b, which are second transport members, are arranged. The developer is circulated in the developing container 2 by the first transport screw 2a and the second transport screw 2b, and is mixed and stirred. In the present embodiment, the direction of the developer circulation is a direction from the near side to the back side in FIG. 1 on the first conveying screw 2a side, and a direction from the back side to the near side in FIG. 1 on the second conveying screw 2b side. .

  The mixing ratio of the toner and the carrier of the replenishment developer is about 9: 1 by weight, but is not particularly limited to this value. That is, the amount of toner is overwhelmingly larger than the ratio of the two-component developer in the developing container 2, and considering the volume ratio, it can be considered that a small amount of carrier is mixed in the toner. That is, a small amount of carrier is gradually supplied when supplementing the toner consumed by image formation.

  When the ratio of the carrier of the developer to be replenished increases, the replacement amount of the carrier increases with the same amount of toner replenishment, and the two-component developer in the developing device 1 approaches a fresh state. Increase. For this reason, it is preferable to determine an appropriate mixing ratio separately for each device.

  When the toner consumption by the image formation and the replenishment by the toner replenishment amount control means are repeated, the amount of the carrier replenished together with the toner replenishment in the developing container 2 increases. Since the toner concentration of the two-component developer is kept substantially constant by the toner supply amount control means, the amount of the developer in the developing container 2 increases. The excess two-component developer is collected in a collection container 5b integrated with the replenishing container 5a, beyond the opening of the developer discharge port 2d.

  Next, replenishment of the developer and collection of the developer will be described in detail.

  Here, the supply container 5a containing the supply toner and the carrier and the collection container 5b for collecting the excess developer (excess developer) in the development container 2 are integrated to constitute the developer cartridge 5. ing.

  As shown in FIG. 3, the developer cartridge 5 includes a substantially cylindrical replenishment developer container 5a that is a replenishment container, and a collected developer container 5b that is a collection container. It can be easily detached from the main body.

  When the developer cartridge 5 is inserted into the image forming apparatus from the near side, the shutter mechanism 6d slides, the developer collecting port 6b is opened, and the handle 5c on the near side is twisted to the right, so that the collected developer accommodating portion is formed. The supply developer container 5a rotates while the reference numeral 5b is fixed to the image forming apparatus main body, and the developer supply port 6a communicating with the developer supply port 2i of the developing container 2 opens.

  When the developer cartridge 5 is detached from the image forming apparatus, the handle 5c is twisted to the left to close both openings 6a and 2i, so that the contained powder does not leak to the outside.

  In addition, a stirring member 7 for stirring the replenished developer is built in the replenishment developer container 5a. FIG. 3 shows a part of the inside of the developer cartridge 5. The stirring member 7 is formed by spirally rotating a resin film or the like as shown in FIG. By appropriately rotating, the developer in the replenishment developer accommodating portion 5a is agitated, and the replenishment of the developer is assisted.

  The toner consumed by the image formation passes through the developer supply port 6a from the supply developer storage section 5a due to the rotational force and gravity of the stirring member 7, and is developed into the developing container 2 as shown in FIG. The developer is conveyed to a replenishing screw 8 provided in the agent replenishing port 2i, and replenished to the stirring chamber 2f side where the developing sleeve 3 is not installed in the developing container 2 according to the rotation of the replenishing screw 8.

  In this way, the supply developer is supplied from the developer cartridge 5 to the developing device 1.

  The toner (and carrier) replenishment amount is roughly determined by the number of rotations of the replenishment screw 8, and the number of rotations is determined by a toner replenishment amount control unit (not shown). There are various methods of controlling the toner supply amount, such as a method of optically or magnetically detecting the toner density of the two-component developer, a method of developing a reference latent image on the photosensitive drum 128 and detecting the density of the toner image, and the like. Since such methods are known, any one of the methods can be appropriately selected.

  The excess amount of the two-component developer due to the toner consumption due to the image formation and the replenishment by the toner replenishment amount control means exceeds the opening of the developer discharge port 2d provided on the stirring chamber 2f side by a developer collection port. The toner is collected by dropping from the collection developer container 6b into the collection developer container 5b.

  Here, the developer supply port 6a and the developer supply port 2i of the developer container 2 are located in the axial direction of the developer container 2 in the direction in which the developer cartridge 5 is inserted. The developer discharge port 2d is located slightly further behind the developer supply port 6a.

  That is, the developer discharge port 2d provided on the side of the stirring chamber 2f is located upstream of the developer supply port 2i with respect to the direction of circulation of the developer in the developer container 2, and is supplied from the developer supply port 2i. The fresh carrier thus obtained is accommodated in the developing container 2 and mixed and stirred with the two-component developer circulated in the stirring chamber 2f for at least one circulation in the developing container 2, and the developer outlet 2d Most of the developer discharged from the developer collecting port 6b and collected in the collected developer accommodating portion 5b is an old developer that has repeatedly formed an image in the developing device 1. In this way, the replacement of the two-component developer is performed gradually.

  In such a developing device, as described in the conventional example, the amount of the developer is excessively increased when the amount of the developer or the bulk density changes and the developer surface in a place other than the outlet becomes unstable. In some cases, a problem arises in that torque is over and high image quality cannot be maintained.

  In the present embodiment, the change in the developer surface near the discharge port during the transfer of the developer with respect to the change in the amount of the developer or the bulk density of the developer is made larger than the change in the developer surface in other places in the developing device. This stabilizes the developer surface in the developing device (reduces the ripple of the discharge amount of the excess developer) and avoids torque over.

  Next, when the amount of the developer or the bulk density, which is a characteristic part of the present embodiment, is changed, and the surface of the developer becomes unstable at a place other than the outlet, the developer is discharged from the developer outlet. The change of the developer surface when the developer is discharged will be described.

  In the present embodiment, the developer surface is adjusted by devising the structure of the second transport screw that agitates and transports the developer in the stirring chamber 2f where the developer is supplied and discharged.

  FIG. 2 shows the vicinity of the developer outlet 2d of the developing device 1 as viewed from the stirring chamber 2f side.

  The first transport screw 2a and the second transport screw 2b are provided with a plurality of screw blades 22, which are agitating blades having a pitch of 24 mm, are uniformly provided on a rotating shaft 21 having an outer diameter of 20 μm in the axial direction. As described above, ribs 2c as agitation promoting members are arranged at equal intervals. However, the rib 2c is not disposed only in the vicinity of the developer outlet 2d of the second transport screw 2b. That is, the carrying capacity of the second carrying screw 2b in the developer carrying direction in the developer carrying direction is large in the region C (FIG. 2) near the outlet 2d, and the region D1 on the upstream side in the developer carrying direction from the vicinity of the outlet and the region on the downstream side. D2 (FIG. 2) is smaller.

  Accordingly, when the developer is transported by rotating the second transport screw 2b, the developer surface becomes as indicated by the solid line A when the amount of the developer is normal. That is, the developer surface is low near the developer outlet 2d, and the screw blades 22 are exposed. On the other hand, the developer surface is high in a region upstream and downstream from the vicinity of the developer discharge port 2d in the developer transport direction, and the screw blades 22 are buried by the developer. Therefore, it is possible to increase the amount of the developer contained in the developing container 2 while adopting a configuration in which the developer is gradually replaced, and for example, to continuously form a plurality of solid images (maximum density images). When performing an image forming job to be performed, it is possible to prevent an image forming defect such as an increase in image density due to a shortage of a charge amount of toner caused by a poor stirring of a developer without lowering an image forming throughput.

  From this state, when the amount of the developer in the developing container 2 increases with the replenishment of the developer, or when the bulk density of the developer in the developing container decreases due to the atmospheric environment, the developer surface changes as indicated by a broken line B. I do. That is, the developer surface in the region C near the developer discharge port 2d rises more sensitively than the developer surfaces in the regions D1 and D2 in the developer transport direction in the downstream direction from the vicinity of the developer discharge port 2d.

  This is because while the developer carrying capacity in the region C near the outlet 2d is large, the developer carrying ability in the region D2 on the downstream side in the developer carrying direction from the vicinity of the outlet 2d is small, so that the developer (toner and carrier) It is considered that when the amount of the developer in the developing container 2 is increased by the replenishment of the developer, the developer shows a movement such that the surplus developer corresponding to the increased amount is discharged from the discharge port 2d.

  Therefore, the developer surface in the areas D1 and D2 in the developer transport direction from the vicinity of the developer discharge port 2d to the downstream in the developer transport direction abnormally rises, and the stirring torque of the developer and the driving torque for driving the second transport screw 2b increase. Before a problem such as the occurrence of a problem occurs, an appropriate amount of excess developer is discharged from the developer discharge port 2d, and the developer surface (particularly, the stirring chamber 2f) in the developing container 2 can always be kept in an appropriate range. .

  In the present embodiment, the developer is adjusted in the vicinity of the developer discharge port 2d and in the areas C, D1, and D2 upstream and downstream thereof with or without the rib 2c installed on the second transport screw 2b. However, the following modified example may be used.

  For example, when the ribs 2c are installed uniformly in the axial direction except for the portion C facing the outlet 2d of the first transport screw 2a and the second transport screw 2b, in the portion C facing the outlet 2d, The ribs 2c may be provided so that the mounting intervals are different from those of the other portions D1 and D2. In such a configuration, the ribs 2c are provided at the outlet 2d of the second transport screw 2b in the same manner as in the above example. Since the developer carrying capacity of the opposing portion C can be made larger than the developer carrying capacity in the areas D1 and D2 on the downstream side in the developer carrying direction from the vicinity of the developer outlet 2d, the same effect as in the above example can be obtained. Can be obtained.

  In addition to the example in which the developer surface is changed depending on the presence or absence of the rib 2c, a method of adjusting the diameter of the screw blade 22 of the second transport screw 2b, the diameter of the rotating shaft 21, or the like may be used. However, by providing the rib 2c to improve the stirring property, the developer tends to stay at the downstream side D1, D2 in the developer transport direction from the discharge port 2d, and the developer surface near the discharge port 2d is discharged to the discharge port 2d. The developer can be raised more sensitively than the developer surfaces in the areas D1 and D2 on the downstream side in the developer transport direction from the vicinity.

  Further, in a region D2 on the downstream side in the developer conveyance direction from the vicinity of the discharge port 2d, the developer may be retained so that the developer contacts the ceiling wall of the developer container 2. The developer surface can be raised more sensitively.

  As described above, according to the developing device of the present invention, a change in the developer surface near the discharge port during the transport of the developer with respect to a change in the developer density due to the amount of the developer accompanying the replenishment of the developer or an atmospheric environment. Is larger than the change in the developer surface at other places in the developing device, so that the inside of the developing device can be maintained at an appropriate developer surface. As a result, the maintenance property is improved by gradually and automatically changing the developer, and even if the developer is reduced in particle size, poor agitation of the replenishment toner, torque over, and the like do not occur, and high image quality is maintained in various environments. The object of the present invention of realizing and providing a developing device can be achieved.

  In the above embodiment, the purpose was achieved by devising the structure of the transport screw by installing a developer supply port and a discharge port in the stirring chamber of the developing container on the side where the developing sleeve was not installed. However, the present invention is not limited to this, and the present invention can be similarly applied to a developer accommodating section in which surplus developer is discharged (that is, automatically replaced).

  For example, the present invention can be applied to a configuration in which a developing container is vertically divided into a developing chamber and a stirring chamber, or a configuration in which a plurality of stirring chambers are provided. When a plurality of agitating chambers are provided, the agitating / transporting member in the agitating chamber provided with the developer outlet serves as the above-described second transport screw.

  Further, the image forming apparatus to which the present invention is applied is not limited to the one shown in FIG.

Example 2
Next, a developing cartridge according to a second embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 4, the developing cartridge 9 according to the present embodiment is such that the developing device 1 and the developer cartridge 5 according to the first embodiment are integrated and can be easily detached from the main body of the image forming apparatus.

  The replenishment developer container 5a is fixed without rotating as in the first embodiment. Before being mounted on the image forming apparatus, the developer supply port 6a and the developer recovery port 6b are sealed by a seal member 6c. The end of the seal member 6c partially protrudes from the front of the developing cartridge 9, and after the developing cartridge 9 is inserted into the main body of the image forming apparatus, the protruding portion of the seal member 6c is pulled out toward the front to supply the developer. The opening 6a and the developer collecting opening 6b are opened.

  Other configurations and a method of collecting the developer are the same as those described in the first embodiment.

Example 3
Next, with reference to FIG. 6, a description will be given of a rotation switching development type image forming apparatus, which is a third embodiment of the present invention, in which a plurality of developing devices 1 in the first embodiment are arranged inside a rotating body (developing rotary). .

  In the electrophotographic image forming apparatus according to this embodiment, the photosensitive drum 128, which is an electrophotographic photosensitive member in which a photosensitive layer made of an organic photosensitive member is formed on a cylindrical substrate, has a predetermined peripheral speed in a direction indicated by an arrow in FIG. It is rotatably mounted.

  In this embodiment, a photosensitive layer made of an organic photosensitive material is formed in an aluminum cylinder having an outer diameter of 50 mm, and a surface protective layer is provided for improving the releasability of the toner and preventing the photosensitive layer from being scraped. .

  The peripheral surface of the photosensitive drum 128 is charged to a predetermined polarity and potential by a charger 121 as charging means. Then, the charged surface is modulated (turned on) in accordance with the pixel signal of the image information output from the exposure unit 122 and input from a not-shown image reading device or an image signal generating device such as a personal computer via a print interface. An electrostatic latent image of image information is formed by performing scanning exposure with the laser light 30 that has been subjected to (/ off conversion).

  The laser light reflecting mirror 31 deflects the output laser light 30 from the exposure unit 122 with respect to the photosensitive drum 128.

  The developing unit 100 includes a switching type rotating body (rotary, rotary developing unit) including a yellow developing device 1Y, a magenta developing device 1M, a cyan developing device 1C, and a black developing device 1K having the same configuration as the developing device 1 in the first embodiment. ) 1a.

  The rotary developing device 1a is rotatably supported in the direction of the arrow in FIG. 6 by a rotary support device 1c, and the above-described color developing devices 1Y, 1M, 1C, and 1K are sequentially opposed to the photosensitive drum 128 to perform development with toner of each color. It has become to be.

  When the surface of the photosensitive drum 128 is charged by the charger 121, next, exposure scanning is performed by the exposure unit 122 that is ON / OFF controlled according to the image data of the first color (for example, yellow), and the first color is scanned. An electrostatic latent image is formed on the photosensitive drum 128. The first-color electrostatic latent image is developed and visualized by a yellow developing device 1Y containing the first-color yellow agent. Then, the visualized first toner image is pressed against the photosensitive drum 128 with a predetermined pressing force, and a speed substantially equal to the peripheral speed of the photosensitive drum 128 (in the present embodiment, In the nip portion with the intermediate transfer body 35 driven to rotate at 100 mm / s) in the direction of the arrow, the image is transferred onto the surface of the intermediate transfer body 35.

  At the time of transfer to the intermediate transfer member 35, a preset voltage is applied to the intermediate transfer member 35 with a polarity opposite to the polarity of the charged toner. The toner remaining on the photosensitive drum 128 without being transferred to the intermediate transfer body 35 at the time of this transfer is scraped off by a cleaning blade 26 a which is a cleaning means pressed against the photosensitive drum 128, and collected in a waste toner container 126. You.

  Then, the above-described transfer process is repeated for the other toners (magenta, cyan, and black) in the same manner, and each time the toner images of different colors included in the respective developing devices 1 are sequentially transferred to the intermediate transfer body 35 and laminated. By doing so, a color image is synthesized and formed.

  In FIG. 6, a cleaner 129 is provided for removing toner remaining from the intermediate transfer member 35 without being transferred from the intermediate transfer member 35 to the transfer material 127.

  The transfer material 127 as a recording material is fed one by one from the feed cassette 11 to the intermediate transfer body 35 by the feed roller 12a and the transport roller 12b, and the toner is transferred to the transfer roller 13 from the back surface of the transfer material 127 with toner. By applying a voltage of the opposite polarity, a full-color toner image on the intermediate transfer body 35 side is transferred and formed on the transfer material 127.

  Then, the transfer material 127 to which the full-color toner image has been transferred is separated from the intermediate transfer body 35, introduced into the fixing unit 125, and is heated and fixed to the toner image and discharged to the discharge tray 15. .

  By mounting the developing device and the developer cartridge on such a rotating body, the present invention can be applied to a color image forming apparatus. By devising the opening and closing of the developer supply port and the developer discharge port, it is possible to mount the developing cartridge described in the second embodiment, in which the developing container and the collecting container are integrated with the developing device, on the rotating body. It is.

  The present invention is also applicable to an inline type image forming apparatus in which a photosensitive drum as an image carrier is provided for each color, and an image forming unit including the developing device is provided for each photosensitive drum.

FIG. 3 is a cross-sectional view illustrating an example of a developing device, a supply container, and a collection container according to the present invention. It is a longitudinal section showing an example of a stirring room concerning the present invention. It is a perspective view showing an example of a supply container and a recovery container concerning the present invention. FIG. 3 is a cross-sectional view illustrating an example of a developing cartridge according to the present invention. FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. FIG. 9 is a schematic configuration diagram illustrating another example of the image forming apparatus according to the present invention.

Explanation of reference numerals

1 Developing device 1a Rotary, rotary developing means (rotary body)
2 Developing container 2a First transport screw (first transport member)
2b Second transport screw (second transport member)
2c rib 2d developer outlet 2h regulating blade (layer thickness regulating member)
3 Developing sleeve (developer carrier)
4 Magnet roller (magnetic field generating means)
5 Developer cartridge 5a Supply developer storage unit (supply container)
5b Collected developer container (collection container)
6a Developer Supply Port 9 Developing Cartridge 21 Rotary Shaft 22 Stirring Blade 128 Photosensitive Drum (Image Carrier)

Claims (8)

A developing container containing a developer containing a toner and a carrier,
A conveying member for conveying the developer in the developing container,
An outlet provided in the developing container for discharging surplus developer accompanying replenishment of the developer,
In the developing device having
The developing device is characterized in that the developer carrying capacity of the carrying member is larger in a region near the outlet than in a region downstream of the outlet in the developer carrying direction.   The developer surface in a region near the outlet is lower than the uppermost portion of the transport member, and the developer surface in a region downstream from the outlet in the developer transport direction is higher than the uppermost portion of the transport member. 2. The developing device according to claim 1, wherein the developer conveying capability of said conveying member is set.   The conveying member has a spiral blade portion provided on a rotating shaft and a stirring rib provided on the rotating shaft, and the developer is supplied from the discharge port without providing the stirring rib in a region near the discharge port. 3. The developing device according to claim 2, wherein the developing device is provided in a region on the downstream side in the transport direction.   2. The developing device according to claim 1, wherein the developer conveying capacity of the conveying member is larger in a region near the outlet than in a region upstream of the outlet in the developer conveying direction. 3.   The developer surface in the area near the outlet is lower than the uppermost part of the transport member, and the developer surface in the upstream and downstream areas in the developer transport direction from the outlet is higher than the uppermost part of the transport member. 5. The developing device according to claim 4, wherein the developer carrying capacity of the carrying member is set so as to be higher.   6. The transporting member according to claim 5, wherein the transporting member has a spiral blade portion for transporting the developer on a rotating shaft, and a stirring rib is provided on the rotating shaft except for a region near the discharge port. Developing device.   The developing container, a developing chamber for developing an electrostatic image on the image carrier, and a stirring chamber provided with the transport member and the discharge port and forming a circulation path of a developer between the developing chamber, The developing device according to claim 1, further comprising: A developing container containing a developer containing a toner and a carrier,
A conveying member for conveying the developer in the developing container,
An outlet provided in the developing container for discharging surplus developer accompanying replenishment of the developer,
Having a developing device for developing an electrostatic image formed on the image carrier,
The transporting member has a spiral blade portion provided on a rotating shaft and a stirring rib provided on the rotating shaft, and the developer flows from the discharge port without providing the stirring rib in a region near the discharge port. A developing device provided in a region on the upstream and downstream sides in the transport direction.

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