JP2000305350A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device where the generation of an unevenness in image density can be suppressed even when an unevenness is generated in a developer pool. SOLUTION: In the device, a projecting part 13 facing a developing sleeve 4 is provided in a supporting case 11 as a developer quantity deviation decreasing member that decreases the deviation in the quantity of developer on a developing sleeve 4 in an axial direction of the developing sleeve more downstream in a carrying direction of the developer 3 on the developing sleeve 4 than a developing range between the developing sleeve 4 and a photoreceptor drum 1 and in a range that is on the upstream side in a carrying direction from a toner feeding part where toner feeding from a toner hopper 8 is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for performing development using a two-component developer among developing devices used for an image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, in a developing device which performs development using a two-component developer using a toner and a carrier, a toner concentration detecting means is not required, and the toner is incorporated into the developer by the movement of the developer. Devices are known. However, in this developing device, the amount of toner taken in is different between a portion where the movement of the developer is active and a portion where the movement of the developer is not so, or a portion where the amount of the developer is large and a portion where the amount of the developer is small. As a result, image density unevenness was likely to occur.

[0003] Japanese Patent Application Laid-Open No. Hei 9-197 previously proposed by the present applicant.
The developing device disclosed in Japanese Unexamined Patent Publication No. 833 is useful as a device capable of solving the above-mentioned problem while reducing the size and cost. The developing device disclosed in Japanese Patent Application Laid-Open No. Hei 9-197833 has a magnetic field generating means therein, and carries and transports a two-component developer containing a toner and a magnetic carrier. A first regulating member that regulates the amount of the developer carried and conveyed by the first regulating member; a developer accommodating portion that accommodates the developer scraped off by the first regulating member; A toner accommodating section for supplying toner to the developer carrier; and changing a contact state between the developer and the toner by changing a toner concentration of the developer on the developer carrier. A developing device for changing a toner take-in state of a developer on a developer carrying member, wherein the developer accommodating portion is located upstream of the first regulating member in a conveying direction of the developer on the developer carrying member. A second regulating member disposed therein, wherein the second regulating member is provided. The member is provided in contact with the developer carrier to regulate the passage of the increased amount of the developer when the toner concentration of the developer on the developer carrier increases and the layer thickness of the developer increases. It is characterized by a gap, and is configured to eliminate the occurrence of abnormal images such as uneven image density and fogging while reducing the size and cost by reducing the number of components.

[0004]

However, even with the developing device having the above-mentioned structure, it was difficult to satisfactorily prevent the image density unevenness.

The inventors of the present invention have conducted intensive studies on the causes of the occurrence of the image density unevenness, and have found the following. In the image density unevenness, when a part where the amount of the developer is partially formed, the toner is taken in as if the toner density is lowered at the toner intake port, and the density of the part locally increases. It is thought to occur. The reason that the amount of the developer can be partially small is that the gap between the developer regulating member and the developer carrier is locally varied,
The accumulation of the developer in the developing area between the developer carrier and the image carrier (hereinafter, referred to as an agent pool) may vary locally. In particular, the dispersion of the agent pool greatly affects the density unevenness.

[0006] Once the dispersion of the agent pool occurs, in a portion where the agent pool is large, the amount of the developer conveyed downstream decreases and toner is supplied more than necessary, so that the toner concentration locally increases. When the toner concentration increases, the fluidity of the developer increases, and the magnetic properties also decrease, so that the conveying force received from the developer carrier is weakened, and the agent pool in the development area further increases, that is, the agent pool grows. . As a result, a portion where toner supply is continuously performed is locally generated, and the toner density is locally increased in this portion, causing local unevenness of the background called image unevenness or band-shaped background stain. It will be.

[0007] Such image density unevenness occurs even in a developing device having a configuration other than the developing device disclosed in JP-A-9-197833, which has a magnetic field generating means therein and contains toner and a magnetic carrier. A developer carrying member that carries and conveys the two-component developer, a first regulating member that regulates the amount of developer carried and carried by the developer carrying member,
A developer accommodating section for accommodating the developer scraped off by the regulating member; and a toner accommodating section adjacent to the developer accommodating section and supplying toner to the developer accommodating section. This can occur in a developing device that changes the state of contact between the developer and the toner by changing the toner concentration of the developer above, thereby changing the state of toner taken in by the developer on the developer carrier. Things.

The present invention has been made in view of the above background, and an object of the present invention is to provide a developing apparatus capable of suppressing the occurrence of image density unevenness even when unevenness occurs in the agent pool.

[0009]

According to a first aspect of the present invention, there is provided a magnetic recording medium having a magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier. A developer carrying member, a first regulating member that regulates an amount of the developer carried and conveyed by the developer carrying member, and a developer accommodating the developer scraped off by the first regulating member. An accommodating portion, and a toner accommodating portion that is adjacent to the developer accommodating portion and supplies toner to the developer carrying member. The toner concentration of the developer on the developer carrying member varies with the developer accommodating portion. In the developing device, which changes the state of contact with the toner to change the state of taking in the toner of the developer on the developer carrier, the direction of transport of the developer on the developer carrier relative to the developing area where the developing operation is performed. On the downstream side, the toner from the toner storage section A developer amount deviation reducing member for reducing the deviation of the amount of developer on the developer carrier in the axial direction of the developer carrier is provided at at least one position on the upstream side in the transport direction from the toner supply unit where the toner is supplied. It is characterized by having been provided.

In this developing device, the deviation of the developer amount on the developer carrier in the axial direction of the developer carrier is reduced by the developer amount deviation reducing member in the axial direction of the developer carrier. This allows the developer on the developer carrier to enter the toner supply unit in a state where the deviation of the amount in the axial direction of the developer carrier is reduced.

According to a second aspect of the present invention, in the developing device according to the first aspect, the magnetic field generating means includes a plurality of magnetic poles, and at least one of the inflection points of the plurality of magnetic poles performs a developing operation. Located in a region downstream of the region in the transport direction of the developer on the developer carrying member and upstream of the toner supply unit in which the toner is supplied from the toner storage unit in the transport direction, and The developer amount deviation reducing member is disposed at the inflection point.

In this developing device, since the developer amount deviation reducing member is located at the inflection point, the developing agent on the developer carrying member follows the surface of the developer carrying member in a state where the developer follows the surface of the developer carrying member. Reduce the deviation in the amount of the agent. Therefore, the amount of the developer is more effectively reduced in a state where the developer on the developer carrier does not follow the surface of the developer carrier, particularly when the deviation of the amount of the developer is reduced in a state where the developer is raised. be able to.

According to a third aspect of the present invention, in the developing device of the first or second aspect, a convex member provided in a case of the developing device is used as the developer amount deviation reducing member. It is.

In this developing device, the deviation of the amount of developer on the developer carrier in the axial direction of the developer carrier is reduced by a convex member provided in the case of the developing device. Specifically, the deviation is reduced by regulating the amount of the developer by the convex member.

According to a fourth aspect of the present invention, in the developing device of the first aspect, an elastic plate-shaped member is used as the developer amount deviation reducing member, and a part of the toner supplied from the toner supply portion is used. Further, the plate-shaped member is provided so as to shut off at a relatively upstream portion in the transport direction in the toner supply section.

In this developing device, the elastic plate provided so as to block a part of the toner supplied from the toner supply unit at a relatively upstream portion in the transport direction in the toner supply unit. The deviation of the amount of the developer on the developer carrier in the axial direction of the developer carrier is reduced by the shape member. Specifically, the deviation is reduced by regulating the developer amount by the plate-like member. Also, once the toner supplied from the toner supply unit is supplied from the entire toner supply unit, once the toner is started to be taken in, the toner take-up becomes unstable because the toner take-up is continued even if the target toner concentration is reached. Cheap. However, in this developing device, a part of the toner supplied from the toner supply unit is blocked by the plate-like member at a relatively upstream portion of the toner supply unit in the transport direction. Therefore, it is possible to prevent the toner intake from becoming unstable.

According to a fifth aspect of the present invention, in the developing device of the fourth aspect, a metal blade is used as the developer amount deviation reducing member.

In this developing device, the metal blade, which is more durable than a member made of a material other than metal, such as a resin material, is provided with the developer carrier in the axial direction of the developer carrier. Reduces deviations in the amount of developer on the body. Specifically, the deviation is reduced by regulating the amount of developer on the developer carrying member by the metal blade.

According to a sixth aspect of the present invention, in the developing device of the fourth or fifth aspect, a magnetic blade is used as the developer amount deviation reducing member.

In this developing device, the deviation of the amount of developer on the developer carrier in the axial direction of the developer carrier is reduced by the magnetic blade. Specifically, the blade reduces the deviation by controlling not only the amount of the developer mechanically but also magnetically.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a developing device of an image forming apparatus such as a copying machine, a facsimile, a printer, etc., more specifically, a developing device having a magnetic field generating means therein and containing a toner and a magnetic carrier. A developer carrying member that carries and transports the component developer, a first regulating member that regulates the amount of the developer that is carried and transported by the developer carrying member, and scraping off by the first regulating member. A developer accommodating section for accommodating the obtained developer;
A toner storage unit that is adjacent to the developer storage unit and supplies toner to the developer carrier, wherein a change in toner concentration of the developer on the developer carrier causes the developer and the toner to be in contact with each other. A developing device for changing a contact state to change a toner take-in state of a developer on the developer carrier, wherein the developer accommodating portion is more on the developer carrier than the first regulating member. A second regulating member disposed on an upstream side in a developer conveying direction, wherein the second regulating member increases a toner concentration of the developer on the developer carrier and increases a layer of the developer; An embodiment will be described in which the present invention is applied to a developing device in which a gap with the developer carrier is set to restrict the passage of the increased amount of the developer when the thickness increases. FIG. 1 is a schematic configuration diagram of a developing device according to the present embodiment. In FIG. 1, a developing device 2 disposed on a side of a cylindrical photosensitive drum 1 serving as an image carrier has a support case 10 as a case in which an opening is formed toward the photosensitive drum 1. A developing sleeve 4 made of a non-magnetic material, which is partly exposed from the opening, and is fixedly disposed inside the developing sleeve 4 as a developer carrying member that carries a developer 3 made of toner and magnetic particles (carrier) on the surface. Magnet roller 5 as the generated magnetic field generating means,
Developer 3 carried and transported on developing sleeve 4
It is mainly composed of a doctor 6 and the like as a first regulating member for regulating the amount of.

The support case 10 contains the toner 3b inside.
The toner hopper 8 is formed as a toner storage unit for storing the toner. A developer accommodating member 11 forming a developer accommodating portion A for accommodating the developer 3 including the toner 3b and the carrier 3a which is a magnetic particle is provided near the photosensitive drum 1 side of the toner hopper 8 integrally with the support case 10. Is provided. The support case 10 located below the developer accommodating member 11 is formed with a protruding portion 10a having an opposing surface 10b opposing the lower portion of the developer accommodating member 11,
A space between the lower part of the developer accommodating member 11 and the facing surface 10b forms a toner supply opening 20 as a toner supply unit for supplying the toner 3b.

Inside the toner hopper 8, there is provided a toner agitator 9 as toner supply means which is rotated by a driving means (not shown). Toner agitator 9
Sends the toner 3b in the toner hopper 8 toward the toner supply opening 20 while stirring. Further, on the side of the toner hopper 8 facing the photosensitive drum 1, there is provided a toner end detecting means 10c for detecting when the amount of the toner 3b in the toner hopper 8 becomes small.

A second doctor 7 as a second regulating member is provided at a portion of the developer accommodating member 11 located near the toner supply opening 20. The second doctor 7 has a free end in a direction in which the flow of the layer of the developer 3 formed on the surface of the developing sleeve 4 is prevented, that is, the free end, in order to maintain a constant gap with respect to the outer peripheral surface of the developing sleeve 4. The base end is integrally attached to the developer accommodating member 7 with the end facing the center of the developing sleeve 4.

The developing sleeve 4 is driven to rotate in a direction indicated by an arrow in FIG.

The magnet roller 5 has four magnetic poles. The magnetic force distributions of these four magnetic poles are shown by broken lines in the figure.

The developer accommodating portion A is configured so as to have a sufficient space for circulating the developer 3 within a range where the magnetic force of the magnet roller 5 in the developing sleeve 4 can reach.

With the above configuration, the toner 3 b sent out by the toner agitator 9 from inside the toner hopper 8
Is supplied to the developer 3 carried on the developing sleeve 4 through the toner supply opening 20 and conveyed to the developer accommodating section A. Then, the developer 3 in the developer accommodating portion A is carried by the developing sleeve 4 and transported to a position facing the outer peripheral surface of the photosensitive drum 1, and the toner 3 b is formed on the photosensitive drum 1. By electrostatically coupling with the latent image,
A toner image is formed on the photosensitive drum 1.

Here, the behavior of the developer 3 during the formation of the toner image will be described with reference to FIGS.
When a starting agent consisting of only the magnetic carrier 3a is set in the developing device 2, the magnetic carrier 3a is magnetically attached to the surface of the developing sleeve 4 and housed in the developer accommodating portion A as shown in FIG. Divided into things to be done. The magnetic carrier 3a accommodated in the developer accommodating section A is moved by the magnet roller 5 with the rotation of the developing sleeve 4 in the direction of arrow a.
Circulates in the direction of arrow b at a moving speed of 1 mm / s or more by the magnetic force of. Then, an interface X is formed at a boundary between the surface of the magnetic carrier 3a magnetically attached to the surface of the developing sleeve 4 and the surface of the magnetic carrier 3a moving in the developer accommodating portion A.

Next, when the toner 3 b is set in the toner hopper 8, the developing sleeve 4 is opened through the toner supply opening 20.
The toner 3b is supplied to the magnetic carrier 3a carried by the. Therefore, the developing sleeve 4 carries the developer 3 which is a mixture of the toner 3b and the magnetic carrier 3a.

In the developer accommodating portion A, a force acting to stop the conveyance of the developer 3 conveyed by the developing sleeve 4 acts due to the presence of the developer 3 contained therein. Then, when the toner 3b present on the surface of the developer 3 carried on the developing sleeve 4 is conveyed to the interface X, the frictional force between the developers 3 near the interface X decreases, and the developer 3 near the interface X decreases. The transport force of the developer 3 decreases, whereby the transport amount of the developer 3 in the vicinity of the interface X decreases.

On the other hand, the developer 3 on the upstream side in the rotation direction of the developing sleeve 4 from the junction Y has the same structure as the developer 3 conveyed by the developing sleeve 4 such as in the developer accommodating section A described above. Since the force for stopping the conveyance does not act, the balance between the amount of the developer 3 conveyed to the junction Y and the amount of the developer 3 conveyed on the interface X is lost, and the developer 3
2B, and as shown in FIG.
Is raised, and the layer thickness of the developer 3 including the interface X increases. Further, the layer thickness of the developer 3 passing through the first doctor 6 also gradually increases, and the increased developer 3 is scraped off by the second doctor 7 at the second doctor restriction position G2.

The developer 3 that has passed through the first doctor 6
When the toner concentration reaches a predetermined toner concentration, as shown in FIG. 2C, the increased amount of the developer 3 scraped off by the second doctor 7 and layered closes the toner supply opening 20, and in this state, The loading of the toner 3b ends. At this time, since the toner concentration in the developer accommodating portion A increases, the developer 3
And the space inside the developer accommodating portion A becomes narrower, so that the moving speed of the developer 3 circulating in the direction of arrow b in the drawing also decreases.

In the layer of the developer 3 formed so as to close the toner supply opening 20, the developer 3 scraped off by the second doctor 7, as shown by an arrow c in FIG. Moves at a moving speed of 1 mm / s or more and faces the opposite surface 1
0b, the opposed surface 10b is inclined downward at an angle α toward the developing sleeve 4 side and has a predetermined length l, so that the toner hopper 8 is moved by the movement of the layer of the developer 3. Can be prevented, and the amount of the developer 3 can be always kept constant. Therefore, the toner supply can be constantly controlled to be constant.

In such a developing device, if the size of a developer pool (hereinafter referred to as a “agent pool”) 12 formed in a developing area between the developing sleeve 4 and the photosensitive drum 1 varies locally, Image density unevenness occurs.
Specifically, the amount of the developer conveyed downstream is reduced in the portion where the agent pool is large, and the toner is taken in at the toner supply opening 20 as if the toner concentration had dropped, that is, the toner was Since the toner is supplied more than necessary, the toner concentration locally increases. When the toner concentration increases, the fluidity of the developer increases, and the magnetic properties also decrease, so that the conveying force received from the developer carrier is weakened, and the agent pool in the development area further increases, that is, the agent pool grows. . As a result, a portion where toner supply is continuously performed is locally generated, and the toner density is locally increased in this portion, causing local unevenness of the background called image unevenness or band-shaped background stain. It will be.

Therefore, in the developing device 2 according to the present embodiment, even if the unevenness of the agent pool occurs, the occurrence of the image density unevenness can be suppressed by suppressing the local increase of the toner concentration of the developer. Is adopted. Hereinafter, this configuration and operation will be described in detail. In the present developing device 2,
At least one location in a region downstream of the developing region in the transport direction of the developer 3 on the developing sleeve 4 and upstream of the toner supply unit in which toner is supplied from the toner hopper 8 in the transport direction. Further, a configuration is provided in which a developer amount deviation reducing member for reducing the deviation of the developer amount in the axial direction of the developing sleeve 4 is provided. In the developing device shown in FIG. 1, a convex portion 13 facing the developing sleeve 4 is provided in the support case 11 as the developer amount deviation reducing member in the region. The convex portion 13 and the developing sleeve 4
Is set to such an extent that the deviation of the amount of the developer carried on the developing sleeve 4 can be reduced. If the gap is too small, the height of the developer becomes uniform over the entire area in the axial direction of the developing sleeve irrespective of the level of the toner concentration, that is, the volume of the developer becomes the same, When the density changes, the toner is not supplied to the place where the toner should be supplied. For this reason, the setting is made to such an extent that the toner can be satisfactorily supplied.

Since the amount of the developer on the developing sleeve 4 conveyed from the developing area is regulated by the convex portion 13, even if the amount of the developer pool becomes locally large, the portion and the surrounding area are not restricted. The difference in the amount of developer from the portion becomes smaller. This suppresses the growth of the above-described agent pool, thereby suppressing a local increase in toner density and suppressing the occurrence of image density unevenness.

Further, in the developing device shown in FIG. 1, the convex portion 13 is provided integrally with the support case 10. Therefore, when designing the shape of the support case 10,
The support case 1
Since 0 may be formed, it is possible to suppress an increase in cost as compared with the case where the developer amount deviation reducing member is provided independently.

In the developing device 2, the convex portion 13 is located at the position of 0 gauss point located in the area among the inflection points (hereinafter referred to as 0 gauss points) of the four magnetic poles of the magnet roller. It is arranged. Developing sleeve 4
Since the upper developer attempts to follow the vector direction of the magnetic field, the developer follows the circumferential direction of the developing sleeve 4 near the 0 Gauss point. For this reason, when the convex portion 13 is disposed at the 0 Gauss point, the convex portion 13 is disposed at a position other than the 0 Gauss point, particularly at the position of the magnetic pole where the developer is in a spike state. In comparison, the effect of regulating the amount of the developer 3 increases. Therefore, the deviation in the amount of the developer can be reduced more favorably.

FIG. 2 is a view showing a modification of the developing device 2 according to the present embodiment. The basic configuration and operation of the developing device 2 are the same as those of the developing device 2 of FIG. In the developing device 2 according to the present modification, a mylar 14 that is a plate member having elasticity is used as the developer amount deviation reducing member, and a part of the toner supplied from the toner supply opening 20 is used. The configuration in which the mylar 14 is disposed so as to block at a relatively upstream portion of the toner supply opening 20 in the developer conveying direction by the developing sleeve 4 is employed. Specifically, the mylar 14 is disposed on the upstream side of the toner supply opening 20 as the toner supply unit so as to be adjacent to the toner supply opening 20. More specifically, the mylar 14 is provided with a deviation of the developer on the surface of the developing sleeve 4 in the axial direction of the developing sleeve 4 at the end of the facing surface 10b on the side of the developing sleeve 4 where the toner supply opening 20 is formed. Are arranged to reduce the By arranging the mylar 14 in this manner, the toner from the toner hopper 8 flows from the gap between the mylar 14 and the second doctor 7 below the developer accommodating member 11 through the toner supply opening 20. The developer is supplied to the developer.

In the developing device according to this modified example, the developer on the developing sleeve 4 is pressed down and regulated by the elasticity of the mylar 14. As a result, even if the agent pool becomes locally large, the difference in the amount of developer between the portion and the surrounding portion becomes small, and the above-mentioned agent pool growth is suppressed. It is possible to suppress the occurrence of image density unevenness. The mylar 14
If the elasticity is too low, the effect of regulation will be reduced,
Conversely, if the elasticity is too high, the regulation will be too strong and toner will not be supplied even when the toner density actually changes. Therefore, it is preferable to set the mylar elasticity to an appropriate value.

Further, in the present developing device, FIG.
As shown in (1), when the toner density is high and bulky, the mylar 14 is pushed toward the toner hopper 8 and at the same time, the developer 3 interferes with the second doctor 7 to stop the toner supply, and the toner density is maintained. It is. Conversely, when the toner density is low, the mylar 14 moves to the developing sleeve 4 side, so that the mylar 1
4 and the second doctor 7 supply the toner 3b.
When the mylar 14 is not at a position upstream of the toner supply opening 20 and adjacent to the toner supply opening 20, the toner is compared with the toner supply opening 20 in the developer conveying direction of the developing sleeve 4. The toner is also supplied from a portion on the upstream side, and the toner is supplied or not supplied due to a minute variation in the amount of the developer. Then, once the toner is started to be taken in, the taking-in of the toner may be continued even if the target toner concentration is attained. Therefore, the taking-in of the toner tends to be unstable. However, by providing the mylar 14 at the above position, the supply of toner from the portion of the toner supply opening 20 relatively upstream of the developing sleeve 4 in the developer conveying direction is shut off. Accordingly, it is possible to prevent the toner taking-up from becoming unstable, and to suppress the occurrence of unevenness on the image.

The material of the plate-like member is not limited to Mylar, and a resin material such as PET may be used. In addition, as the plate member having elasticity, a metal blade may be used. When a metal blade is used, durability is improved as compared with a resin blade, so that a stable image can be obtained for a long period of time.

Further, as the plate member having elasticity,
Using a magnetic metal blade 15, the amount of developer can be regulated by the magnetic force from the developing sleeve 4 to reduce the deviation of the amount of developer. If the amount of the developer is locally fluctuated by the magnetic force, the magnetic force is transmitted via the developer 3 which is a magnetic material. A large portion has a strong magnetic force for regulating the amount of the developer, and a portion having a small amount of the developer has a weak magnetic force for regulating the amount of the developer because a gap is formed between the developer and the blade. Therefore, the effect of reducing the developer amount deviation is enhanced, and a more stable image in which the occurrence of image density unevenness is suppressed can be obtained.

The present invention is not limited to the developing device having the structure described in the above embodiment, but also includes a developing device which has a magnetic field generating means inside and carries and transports a two-component developer containing a toner and a magnetic carrier. Developer carrier, a first regulating member for regulating the amount of developer carried and carried by the developer carrier, and a developer accommodating container for accommodating the developer scraped off by the first regulating member And a toner container that is adjacent to the developer container and supplies toner to the developer carrier.
By the change of the toner concentration of the developer on the developer carrier,
The present invention is applicable to any developing device that changes the state of contact between the developer and the toner to change the state of the developer on the developer carrier in which the toner is taken in.

[0046]

According to the first to sixth aspects of the present invention, even if the unevenness occurs in the developer pool, the deviation of the amount of the developer on the developer carrier can be reduced, so that the image density unevenness occurs. There is an excellent effect that can be suppressed.

Further, according to the developing device of the second aspect, there is an excellent effect that the occurrence of image density unevenness can be suppressed more favorably.

In particular, according to the developing device of the third aspect, there is an excellent effect that it is possible to suppress the increase in cost by forming the convex member integrally with the case of the developing device.

Further, according to the developing device of the fourth aspect, there is an excellent effect that the occurrence of image density unevenness can be suppressed more favorably.

According to the developing device of the fifth aspect, there is an excellent effect that the occurrence of image density unevenness can be suppressed for a long period of time.

According to the developing device of the sixth aspect, there is an excellent effect that the occurrence of image density unevenness can be suppressed more favorably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a developing device according to an embodiment.

FIGS. 2A to 2C are diagrams illustrating behavior of a developer when forming a toner image.

FIG. 3 is a schematic configuration diagram of a modified example of the developing device according to the embodiment.

FIGS. 4A and 4B are explanatory diagrams for explaining a state of toner supply in the developing device. FIGS.

FIG. 5 is an explanatory diagram of a magnetic force generated when a magnetic metal blade is used as a plate member of the developing device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 developing device 3 developer 3b toner 4 developing sleeve 5 magnet roller 6 first doctor 7 second doctor 8 toner hopper 11 developer accommodating member 20 toner supply opening A developer accommodating portion 13 convex portion 14 mylar 15 magnetism Metal blade

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hideo Yoshizawa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Shinji Tamaki 1-3-6 Nakamagome, Ota-ku, Tokyo Stock In Ricoh Company (72) Inventor Junichi Terai 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company (72) Inventor Kiyonori Tsuda 1-3-6 Nakamagome, Ota-ku, Tokyo Stock Company Ricoh Company ( 72) Inventor Masayuki Yamane 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 2H031 AC08 AC19 AC30 AC31 AD11 AD13 AE02 BA04 DA01 2H077 AA11 AC16 AD11 AD13 AD23 AD32 CA02 EA03 FA19 FA26

Claims (6)

[Claims] 1. A developer carrier having a magnetic field generating means therein for carrying and transporting a two-component developer containing a toner and a magnetic carrier, and a developing device carried and transported by the developer carrier. A first regulating member for regulating the amount of the developer, a developer accommodating portion for accommodating the developer scraped off by the first regulating member, and a developer adjoining the developer accommodating portion, A toner container for supplying toner, and the toner concentration of the developer on the developer carrier
In a developing device that changes the state of contact between the developer and the toner to change the state of toner taken in by the developer on the developer carrier, the development on the developer carrier is performed more than the development area where the developing operation is performed. A developer carrying member in the axial direction of the developer carrying member at at least one position downstream of the toner supply portion where the toner is supplied from the toner storage portion and downstream of the toner supply portion where the toner is supplied from the toner storage portion; A developing device comprising a developer amount deviation reducing member for reducing the deviation of the amount of developer. 2. The developing device according to claim 1, wherein the magnetic field generating means has a plurality of magnetic poles, and at least one of the inflection points of the plurality of magnetic poles is larger than the developing area where the developing operation is performed. The developer is located on the downstream side in the transport direction of the developer on the carrier, and is located in an area on the upstream side in the transport direction with respect to the toner supply unit where the toner is supplied from the toner storage unit, and the developer amount A developing device, wherein a deviation reducing member is disposed at the inflection point. 3. The developing device according to claim 1, wherein a convex member provided in a case of the developing device is used as the developer amount deviation reducing member. 4. The developing device according to claim 1, wherein an elastic plate-shaped member is used as said developer amount deviation reducing member, and a part of the toner supplied from said toner supply portion is supplied to said toner supply portion. 3. The developing device according to claim 1, wherein the plate-shaped member is disposed so as to block at a relatively upstream portion in the transport direction. 5. The developing device according to claim 4, wherein a metal blade is used as said developer amount deviation reducing member. 6. The developing device according to claim 4, wherein a magnetic blade is used as said developer amount deviation reducing member.