JP4095544B2 - Development device - Google Patents

Description

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

  2. Description of the Related Art In conventional image forming apparatuses, in particular, electrophotographic image forming apparatuses that form chromatic images, a two-component developing system that uses a mixture of nonmagnetic toner and magnetic carrier as a developer is widely used. .

  The two-component development method has advantages such as image quality stability and device durability compared to other currently proposed development methods, while developer deterioration, especially carrier deterioration, due to long-term durability. Since this is unavoidable, it is necessary to perform an operation of changing the developer along with the long-term use of the image forming apparatus.

  On the other hand, in recent full-color copiers / printers, in order to reduce running costs, the following techniques have been introduced as methods for maintaining high image quality without performing developer replacement work.

  For example, according to Patent Document 1, “in the developing device for an electrophotographic copying machine including a stirring unit that stirs the carrier and the toner, and a developing roll that supplies the developer stirred by the stirring unit to the photosensitive member. Since the carrier replenishing device and the toner replenishing device are provided separately or integrally above the means, and the developer overflow portion is provided on the side wall of the developing device housing, new developer is gradually replenished by the replenishing device and the developing The developer can be discharged from the overflowing portion of the developer, and the characteristics of the developer in the developing device housing can be maintained constant. As a result, the image quality of the copy can be maintained constant. " "Old developer in the developing device housing is automatically and sequentially discharged from the developer overflow portion. Remove the old developer in the housing of the unit, refill it with new developer, and then re-install the developer unit, so that the troublesome work of replacing the developer becomes unnecessary and the developer scattering is prevented. 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 developer as a whole are stabilized. This eliminates the need for developer replacement and improves maintainability.

  However, in recent full-color copiers / printers, the toner and carrier in the developer have been reduced in particle size in order to achieve high image quality. The developer tribo changes with respect to the amount. Accordingly, the change in the bulk density of the developer in the developing device also increases. Specifically, when the amount of water decreases, the tribo increases and the bulk density decreases. Conversely, when the amount of water increases, the tribo is lowered and the bulk density is increased.

  If the developer amount is made constant in this state, the bulk density is lowered and the developer surface is raised, or the bulk density is raised and the developer surface is lowered.

  In the conventional technique, 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 the developer surface constant.

  However, if the developer surface is not stabilized due to the change in the bulk density of the developer as described above, the developer is not suitably discharged, and the balance between the amount of developer to be replenished and the amount of developer to be discharged is poor. Thus, the amount of developer in the developing device gradually increases and the developer surface 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 developer may be agitated due to poor stirring of the replenishment toner or the developer bulk density change described above. If the amount increases too much, torque may be exceeded, which may cause a problem that high image quality cannot be maintained.
Japanese Patent Publication No. 2-21591

  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 excess developer while improving the maintainability by gradually and automatically replacing the developer.

  Another object of the present invention is to provide a developing device capable of increasing the amount of developer accommodated in the developing container while adopting a configuration in which the developer is gradually and automatically replaced.

The above object is achieved by the developing device according to the present invention. In summary, the present invention provides a developer container containing a developer containing toner and carrier;
A replenishment port provided in the developing container and replenished with replenishment developer including toner and carrier;
A developing chamber provided in the developing container and provided with a developer carrying member that carries and conveys the developer to develop an electrostatic latent image;
A stirring chamber provided in the developing container and constituting a circulation path of the developer with the developing chamber;
A conveying member that is provided in the stirring chamber and rotates to convey the developer in the rotation axis direction ;
Wherein provided on a portion in the rotation axis direction of the rotation axis direction along the wall of the conveying member in the stirring chamber, wherein the developer container developer Thus the developer surface to the supply exceeds the predetermined height of the replenishment developer A discharge port for overflowing outside ,
In a developing device having
Wherein the rotation axis direction of the developer conveying capacity of the conveying member, from said discharge opening than in the region of the developer conveyance direction downstream side and the upstream side, a developing device, characterized in that the larger the discharge opening neighborhood region I will provide a.

The developing device of the present invention is provided with a developing container for containing a developer containing toner and a carrier, a replenishing port provided in the developing container and replenished with a replenishing developer containing toner and a carrier, and a developing container. A developer chamber provided with a developer carrier for carrying and transporting the developer to develop the electrostatic latent image, an agitator chamber provided in the developer container and constituting a developer circulation path between the developer chamber, and an agitator provided within the chamber, a conveying member for conveying the developer in the rotation axis direction by rotating, is provided in a portion in the rotation axis direction of the rotation axis direction along the wall of the conveying member in the stirring chamber, supply developer in the developing device having a discharge port for replenishing the result developer surface of the agent causes to overflow the developer exceeds a predetermined height to the outside of the developing container, the developer conveying capacity of the rotary shaft direction in the conveying member, developer conveying direction downstream side from the discharge port Than fine upstream region, so is larger configuration towards the region of the discharge opening neighborhood, and monochrome image forming apparatus, in a full-color image forming apparatus of various configurations, including rotary type, the developer is gradually It can be automatically replaced and discharged with an increased sensitivity to the excess developer, improving maintainability, and avoiding poor stirring and torque over even when the developer size is reduced, while adopting a trickle configuration In addition, since the number of developer openings in the developing container can be increased, it is possible to cope with solid continuous jobs and maintain high image quality in various environments.

  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 for explaining a developing device of this embodiment, and FIG. 5 is a diagram for explaining an example of an image forming apparatus using this 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, and in FIG. 5, the surface of the photosensitive drum 128 charged by a charger 121 is first applied by a laser 122. By exposing, an electrostatic latent image is formed 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 peeled off from the transfer belt 124 and is pressed / heated by the fixing device 125. Get a permanent image. 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 nonmagnetic toner and a magnetic carrier, and the mixing ratio is approximately 1: 9 by weight. This ratio should be appropriately adjusted according to the charge amount of the toner, the carrier particle size, the configuration of the image forming apparatus, and the like, and does not necessarily have to follow this value.

  In the developing device 1, a developing region facing the photosensitive drum 128 is opened, and a developing sleeve 3 that is a developer carrying member is rotatably disposed so as to be partially exposed to the opening. The developing sleeve 3 containing the fixed magnet 4 which is a magnetic field generating means is made of a nonmagnetic 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 electrostatic latent image formed on the photosensitive drum 128 is developed by being carried and conveyed to the developing area and supplied to the developing area facing the photosensitive drum 128. The developer after developing the electrostatic latent image is conveyed according to the rotation of the developing sleeve 3 and collected in the developing container 2.

  The developing container 2 is partitioned by a partition wall 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, and the first chamber 2e and the second chamber 2f are respectively The 1st conveyance member and the 1st conveyance screw 2a and the 2nd conveyance screw 2b which are the 2nd conveyance members are arranged. The first conveying screw 2a and the second conveying screw 2b are circulated through the developing container 2 and mixed and stirred. In this embodiment, the developer circulation direction is the direction from the near side to the far side in FIG. 1 on the first transport screw 2a side, and the direction from the far side to the near side in FIG. 1 on the second transport screw 2b side. .

  The mixing ratio of toner and carrier of the replenishment developer is about 9: 1 by weight, but is not particularly limited to this value. That is, the toner amount is overwhelmingly large with respect to 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 replenished when the toner consumed by the image formation is supplemented.

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

  When toner consumption due to image formation and replenishment by the toner replenishment amount control means are repeated, the number of carriers replenished in the developing container 2 at the time of toner replenishment increases. Since the toner concentration of the two-component developer is kept substantially constant by the toner replenishment amount control means, the amount of developer in the developer container 2 increases. The excess two-component developer is recovered in a recovery container 5b integrated with the supply container 5a in an amount exceeding the opening of the developer discharge port 2d.

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

  Here, the replenishment container 5a containing the replenishment toner and the carrier and the recovery container 5b for recovering the excess developer (surplus developer) in the developing container 2 are integrated to form the developer cartridge 5. ing.

  As shown in FIG. 3, the developer cartridge 5 includes a substantially cylindrical replenishment developer accommodating portion 5a that is a replenishing container portion, and a recovered developer accommodating portion 5b that is a recovering container portion, and is an image forming apparatus. It can be easily detached from the main body.

  When the developer cartridge 5 is inserted into the image forming apparatus from the front side, the shutter mechanism 6d slides, the developer recovery port 6b is opened, and the handle 5c on the front side is further twisted to the right side, whereby the recovered developer accommodating portion. The replenishment developer accommodating portion 5a rotates while 5b is fixed to the image forming apparatus main body, and the developer replenishment port 6a communicating with the developer replenishment port 2i on the developer container 2 side is opened.

  When the developer cartridge 5 is detached from the image forming apparatus, the opening 5a, 2i is closed by twisting the handle 5c to the left side, so that the contained powder does not leak outside.

  Further, a stirring member 7 for stirring the supplied developer is built in the supplied developer storage portion 5a. FIG. 3 shows a part of the inside of the developer cartridge 5, and the stirring member 7 is formed by spirally rotating a resin film or the like with a rigid shaft as shown. By appropriately rotating, the developer in the replenishment developer accommodating portion 5a is stirred, 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 container 5a by the rotational force and gravity of the stirring member 7, and develops in the developer container 2 as shown in FIG. The toner is transported to the replenishing screw 8 disposed in the agent replenishing port 2i, and is replenished to the agitating chamber 2f side in the developing container 2 where the developing sleeve 3 is not installed as the replenishing screw 8 rotates.

  In this way, the replenishment developer is replenished from the developer cartridge 5 to the developing device 1.

  Further, the replenishment amount of the toner (and carrier) is roughly determined by the rotational speed of the replenishment screw 8. This rotational speed is determined by a toner replenishment amount control means (not shown). There are various methods for controlling the toner replenishment amount, such as a method for optically or magnetically detecting the toner density of the two-component developer, a method for developing the reference latent image on the photosensitive drum 128 and detecting the density of the toner image. Since any method is known, any method can be selected as appropriate.

  As for the two-component developer that has become excessive due to toner consumption due to image formation and replenishment by the toner replenishment amount control means, the amount exceeding the opening of the developer discharge port 2d provided on the stirring chamber 2f side is the developer recovery port. It is recovered by dropping from 6b to the recovered developer container 5b.

  Here, the developer replenishing port 6a and the developer replenishing port 2i of the developing container 2 are in the developer cartridge 5 insertion direction from the back side in the axial direction of the developing container 2, and the developer collecting port 6b and the developing container 2 are developed. 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 in the developer circulation direction in the developer container 2, and is supplied from the developer supply port 2i. The fresh carrier thus prepared is accommodated in the developing container 2 and mixed and stirred with the two-component developer circulated in the stirring chamber 2f at least for one circulation in the developing container 2, and the developer discharge port 2d. Most of the developer discharged from the developer recovery port 6b and collected in the collected developer container 5b is an old developer that has repeatedly formed an image in the developing device 1. In this way, the two-component developer is gradually replaced.

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

  In this example, the change in the developer surface in the vicinity of the discharge port during the conveyance of the developer with respect to the change in the developer amount and the bulk density of the developer is made larger than the change in the developer surface in other places in the developing device. In this way, the developer surface in the developing device is stabilized (reduction in ripple of excess developer discharge amount), and torque over is avoided.

  Next, development from the developer outlet, which is a characteristic part of this embodiment, such as when the developer amount or bulk density has changed and the developer surface at a place other than the outlet becomes unstable, etc. A change in the developer surface when the developer is discharged will be described.

  In this embodiment, the developer surface is adjusted by devising the structure of the second conveying screw for agitating and conveying the developer in the agitating chamber 2f where the developer is replenished and discharged.

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

  The first conveying screw 2a and the second conveying screw 2b are provided with a plurality of screw blades 22 that are stirring blades having a pitch of 24 mm in the axial direction on a rotating shaft 21 having an outer diameter of 20 μm. In this way, ribs 2c as stirring promoting members are arranged at equal intervals. However, the rib 2c is not disposed only in the vicinity of the developer discharge port 2d of the second conveying screw 2b. That is, the transporting capability in the developer transport direction by the second transport screw 2b is large in the region C (FIG. 2) in the vicinity of the discharge port 2d, and the region D1 on the upstream side in the developer transport direction from the vicinity of the discharge port and the region on the downstream side. It is smaller at D2 (FIG. 2).

  Accordingly, when the developer is transported by rotating the second transport screw 2b, the developer surface becomes a solid surface A when the developer amount is normal. That is, the developer surface is low in the vicinity of the developer discharge port 2d, and the screw blades 22 are exposed. On the other hand, in the region upstream and downstream of the developer discharge direction from the vicinity of the developer discharge port 2d, the developer surface is high, and the screw blades 22 are buried with the developer. Accordingly, it is possible to increase the amount of developer accommodated in the developing container 2 while adopting a configuration in which the developer is gradually replaced. For example, a plurality of solid images (maximum density images) are continuously formed. When an image forming job is performed, it is possible to prevent an image formation failure such that the image density is increased due to a shortage of charge amount of toner due to a developer agitation failure without reducing the image formation throughput.

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

  This is because the developer transport capability in the region C in the vicinity of the discharge port 2d is large, while the developer transport capability in the region D2 downstream from the vicinity of the discharge port 2d in the developer transport direction is small, so that the developer (toner and carrier). This is because when the amount of developer in the developer container 2 increases due to the replenishment of the developer, the developer exhibits such a movement that the excess developer corresponding to the increased amount is discharged from the discharge port 2d.

  Accordingly, the developer surfaces in the areas D1 and D2 upstream and downstream in the developer conveyance direction from the vicinity of the developer discharge port 2d rise abnormally, and the developer agitation is poor and the driving torque for driving the second conveyance screw 2b increases. Before such a problem occurs, an appropriate amount of excess developer is discharged from the developer discharge port 2d, and the developer surface (especially the stirring chamber 2f) in the developing container 2 can always be kept in an appropriate range. .

  In the present embodiment, adjustment is made with or without the rib 2c installed on the second conveying screw 2b so that the developer surface in the vicinity of the developer discharge port 2d and the upstream and downstream areas C, D1, and D2 are different. However, the following modifications may be possible.

  For example, when the ribs 2c are evenly installed in the axial direction except for the portion C facing the discharge port 2d of the first transport screw 2a and the second transport screw 2b, in the portion C facing the discharge port 2d, The rib 2c may be installed so that the mounting interval is different from that of the other portions D1 and D2. With such a configuration, the discharge port 2d of the second conveying screw 2b is provided in the same manner as in the above example. Since the developer conveying capability of the facing portion C can be made larger than the developer conveying capability in the areas D1 and D2 upstream and downstream in the developer conveying direction from the vicinity of the developer discharge port 2d, the same effect as in the above example Can be obtained.

  In addition to the example in which the developer surface is made different with or without the rib 2c, a method of adjusting the diameter of the screw blade 22 of the second conveying screw 2b, the diameter of the rotating shaft 21, or the like may be used. However, the rib 2c is provided to improve the agitation so that the developer stays on the downstream side D1 and D2 in the developer conveying direction from the discharge port 2d, and the developer surface in the vicinity of the discharge port 2d is located at the discharge port 2d. It can be raised more sensitively than the developer surface in the areas D1 and D2 downstream from the vicinity in the developer transport direction.

  Further, the developer may stay in the region D2 downstream from the vicinity of the discharge port 2d so as to come into contact with the ceiling wall of the developer container 2, and by adopting such a configuration, the developer in the vicinity of the discharge port 2d. The developer surface can be raised more sensitively.

  As described above, with the developing device of the present invention, the change in the developer surface in the vicinity of the discharge port during developer conveyance with respect to the change in the developer bulk density due to the amount of developer accompanying the developer replenishment and the atmospheric environment Is larger than the change in the developer surface at other locations in the developing device, so that the inside of the developing device can be maintained at an appropriate developer surface. As a result, the developer is gradually replaced automatically to improve maintainability, and even if the developer is made smaller in size, it does not cause poor stirring of the replenishing toner, torque over, etc., and maintains high image quality in various environments. The object of the present invention of realizing and providing a developing device can be achieved.

  In the above-described embodiment, the object is achieved by installing the developer supply port and the discharge port in the stirring chamber on the side where the developing sleeve is not installed in the developing container, and devising the structure of the conveying screw. However, the present invention is not limited to this, and the present invention can be similarly applied to any developer container that discharges excess developer (that is, automatic replacement).

  For example, the present invention can be applied to a configuration in which the developing container is partitioned into a developing chamber and an agitating chamber and a configuration in which a plurality of agitating chambers are provided. When a plurality of agitation chambers are provided, the agitation / conveyance member in the agitation chamber provided with the developer discharge port is the above-described second conveyance screw.

  The image forming apparatus to which the present invention is applied is not limited to that 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 of the present embodiment is one in which the developing device 1 and the developer cartridge 5 of the first embodiment are integrated and can be easily detached from the image forming apparatus main body.

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

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

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

  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 the direction of the arrow in FIG. It is mounted for rotation.

  In this embodiment, a photosensitive layer made of an organic photosensitive material is formed in an aluminum cylinder shape having an outer diameter of 50 mm, and a surface protective layer is provided to further improve the toner releasability and prevent 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 which is a charging unit. Then, the charged surface is modulated (ON) corresponding to the pixel signal of the image information output from the exposure unit 122 and input from the image signal generator (not shown) such as an image reading device or a personal computer via the print interface. An electrostatic latent image of image information is formed by performing scanning exposure with the laser light 30 subjected to / off conversion.

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

  The developing unit 100 includes a switchable rotating body (rotary, rotating developing unit) that includes 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 means 1a is supported by a rotation support device 1c so as to be rotatable in the direction of the arrow in FIG. 6, and the color developing devices 1Y, 1M, 1C, and 1K described above sequentially face the photosensitive drum 128 and perform development with each color toner. It has come to be.

  When the surface of the photosensitive drum 128 is charged by the charger 121, exposure scanning is performed by the exposure unit 122 that is ON / OFF controlled in accordance with the image data of the first color (for example, yellow). An electrostatic latent image is formed on the photosensitive drum 128. The electrostatic latent image of the first color is developed and visualized by a yellow developing device 1Y containing a yellow agent of the first color. The visualized first toner image is brought into pressure contact with the photosensitive drum 128 with a predetermined pressing force, and is at a speed approximately equal to the peripheral speed of the photosensitive drum 128 (in this embodiment, 100 mm / s), the image is transferred to the surface of the intermediate transfer member 35 at the nip portion with the intermediate transfer member 35 that is driven to rotate in the direction of the arrow.

  At the time of transfer to the intermediate transfer member 35, a preset voltage having a polarity opposite to the charging polarity of the toner is applied to the intermediate transfer member 35. 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. The

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

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

  A transfer material 127 as a recording material is fed from the feeding cassette 11 to the intermediate transfer member 35 one by one by a feeding roller 12a and a conveying roller 12b, and toner and toner are transferred from the back surface of the transfer material 127 to the transfer roller 13. By applying a reverse polarity voltage, a full color toner image on the intermediate transfer member 35 side is transferred and formed on the transfer material 127.

  Then, the transfer material 127 that has received the transfer of the full-color toner image is separated from the intermediate transfer body 35 and introduced into the fixing unit 125, and the toner image is heated and fixed 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 also be applied to a color image forming apparatus. In addition, by devising the opening and closing of the developer replenishment port and the developer discharge port, it is possible to mount the developing cartridge in which the developing container, the collection container and the developing device described in the second embodiment are integrated on the rotating body. It is.

  The present invention can also be applied to an in-line image forming apparatus in which a photosensitive drum as an image carrier is installed for each color, and an image forming unit including the developing device is installed for each photosensitive drum.

It is sectional drawing which shows an example of the image development apparatus, supply container, and collection | recovery container which concern on this invention. It is sectional drawing of the longitudinal direction which shows an example of the stirring chamber which concerns on this invention. It is a perspective view which shows an example of the supply container and collection | recovery container which concern on this invention. FIG. 3 is a cross-sectional view illustrating an example of a developing cartridge according to the present invention. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention. It is a schematic block diagram which shows the other example of the image forming apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developing apparatus 1a Rotary, rotary developing means (rotating body)
2 Developing container 2a First conveying screw (first conveying member)
2b Second conveying screw (second conveying member)
2c rib 2d developer outlet 2h regulating blade (layer thickness regulating member)
3 Development sleeve (developer carrier)
4 Magnet roller (magnetic field generating means)
5 Developer cartridge 5a Supply developer container (supply container)
5b Recovered developer container (collection container)
6a Developer supply port 9 Developer cartridge 21 Rotating shaft 22 Agitation blade 128 Photosensitive drum (image carrier)

Claims (3)

A developer container containing a developer including toner and carrier;
A replenishment port provided in the developing container and replenished with replenishment developer including toner and carrier;
A developing chamber provided in the developing container and provided with a developer carrying member that carries and conveys the developer to develop an electrostatic latent image;
A stirring chamber provided in the developing container and constituting a circulation path of the developer with the developing chamber;
A conveying member that is provided in the stirring chamber and rotates to convey the developer in the rotation axis direction ;
Wherein provided on a portion in the rotation axis direction of the rotation axis direction along the wall of the conveying member in the stirring chamber, wherein the developer container developer Thus the developer surface to the supply exceeds the predetermined height of the replenishment developer A discharge port for overflowing outside ,
In a developing device having
Wherein the rotation axis direction of the developer conveying capacity of the conveying member, from said discharge opening than in the region of the developer conveyance direction downstream side and the upstream side, a developing device, characterized in that the larger the discharge opening neighborhood region . The developer surface in the vicinity of the discharge port is lower than the uppermost portion of the transport member, and the developer surface in the downstream and upstream regions in the developer transport direction from the discharge port is lower than the uppermost portion of the transport member. The developing device according to claim 1, wherein the developer conveying capability of the conveying member is set so as to be higher. The conveying member has a spiral blade provided on a rotation shaft and a stirring rib provided on the rotation shaft, and the developer is provided from the discharge port without providing the stirring rib in a region near the discharge port. 3. The developing device according to claim 1 , wherein the developing device is provided in a region on the downstream side and the upstream side in the transport direction.

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