JP2003280381A - Developing device and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize the autonomous control of toner concentration in a developer and electrostatic charging and to obtain a uniform developing performance without any density unevenness. <P>SOLUTION: The developing device is equipped with a developer carrier 1 which is equipped with a magnetic field producing means inside and conveys and carriers a two-component developer G containing a toner T and a magnetic carrier C (Fig. 2 and Fig. 3), a restriction member 2 which limits the amount of a developer carried onto the developer carrier 1, a developer storage part 3 which is adjacent to the developer carrier 1 and stores the developer G upstream from the restriction member 2, a toner storage part 4 which is linked with the developer carrier 1 through the developer storage part 3 and stores the toner T in a suppliable state, and a rotating member 5 which is provided in the developer storage part 3 and rotates in contact with or closely to the developer carrier 1 and takes the toner from the toner storage part 4 in the developer storage part 3 while applying a turning force to the developer G in the developer storage part 3. <P>COPYRIGHT: (C)2004,JPO

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 visualizing an electrostatic latent image formed on an image carrier, and more particularly, to a developing device.
The present invention relates to a developing device that uses a two-component developer containing a toner and a carrier and that can autonomously control the toner concentration without using a toner concentration detecting unit, and an improvement in an image forming apparatus using the developing device.

[0002]

2. Description of the Related Art Generally, as a developing device used in an electrophotographic image forming apparatus, an electrostatic latent image formed on an image bearing member such as a photosensitive drum is visualized by a developer. Things are known. This type of developing device has a mode in which a two-component developer containing a toner and a carrier is used as a developer or a mode in which a one-component developer containing only a toner is used, but a two-component developer is used. In this mode, the toner density decreases as the toner consumption increases, so that the toner is replenished periodically to maintain the toner density. Such toner replenishment is performed, for example, when the toner density is detected by a toner density detection sensor and it is determined that the toner density has decreased based on the detection information.

However, in this type of system, the toner density detection sensor must detect the toner density, so that the toner density detection sensor is not only indispensable, but also a density patch to be detected is created. However, there is a problem that the toner concentration detection system is troublesome.
So, as a prior art to solve such a defect,
There has already been provided a developing device that takes in toner by the movement of the developer and autonomously controls the toner concentration without using the toner concentration detection sensor.

As a typical aspect of this type of prior art,
For example, there is one described in Japanese Examined Patent Publication No. 5-67233 (Prior Art 1). This is because the magnetic particle layer is formed on the developing sleeve, the toner is accommodated in the toner supply portion in the container so as to come into contact with the magnetic particle layer, and the magnetic particles in the magnetic particle layer move as the developing sleeve rotates. In the developing device, the toner is taken into the magnetic particle layer from the outer toner layer in the toner supply unit, and the developer in which the toner and the magnetic particles are mixed is regulated by the regulation member to the layer thickness and conveyed to the developing unit. Here, the magnet fixed in the developing sleeve does not have a magnetic pole facing the toner supply section, but has a magnetic pole on the downstream side of the toner supply section with respect to the developing sleeve rotation direction and on the upstream side of the regulating member. A shielding member is provided at a position within the range of the magnetic field of the magnetic pole so as to face the developing sleeve, and forms a region filled with the magnetic particle layer between the developing sleeve and the developing sleeve.

Prior art 2 (Japanese Patent Laid-Open No. 9-19783)
Japanese Patent Laid-Open No. 3) discloses a developer carrier which has a magnetic field generating means therein and carries and conveys a two-component developer including a toner and a carrier, and a first carrier which regulates the amount of the developer on the developer carrier.
Regulating member, a second regulating member which is provided on the upstream side of the first regulating member and which allows an increase in the developer layer thickness accompanying the increase in toner concentration to pass therethrough, the first regulating member and the second regulating member. A developer accommodating portion provided between the regulating member and a toner accommodating portion that is adjacent to the developer accommodating portion and supplies toner to the developer carrier is provided. There is disclosed a technique in which the contact state between the developer and the toner is changed to change the toner intake state of the developer on the developer carrier to constantly control the toner supply constantly.

Further, the prior art 3 (Japanese Patent Laid-Open No. 2001-117)
No. 370), a developer carrier that has a magnetic field generating means therein and carries and conveys a two-component developer including a toner and a carrier, and an amount of the developer on the developer carrier are regulated. A regulating member, a developer accommodating portion for accommodating the developer scraped off by the regulating member, and a developer adjoining the developer accommodating portion so as to come into contact with the developer on the developer carrying member to be taken in. And a toner accommodating portion for accommodating the toner, and further, the developer accommodating portion is provided with a rotating member that is in contact with or close to the developer carrying member and rotates in the same rotation direction as the developer carrying member. A technique is disclosed in which a rotating member is arranged at the most upstream position in the surface moving direction of the developer carrying member in the developer containing portion to stabilize the toner supply from the upstream toner containing portion.

Furthermore, the prior art 4 (Japanese Patent Laid-Open No. 2000-6
No. 6497), a developer carrying member, a first restricting member for restricting the amount of developer on the developer carrying member, and a developer carrying member provided on the upstream side of the first restricting member. A second regulating member for regulating the amount of developer, a developer accommodating portion provided between the first and second regulating members for accommodating the developer scraped off by the first regulating member, and the developing device. A toner storage unit that is adjacent to the developer storage unit and stores the toner to be replenished to the developer carrier, and connects the toner storage unit and the developer storage unit to take in the toner in the toner storage unit A toner replenishing passage for forming a developer circulating portion for optimizing the density, and a stirring member provided in the toner replenishing passage for stirring the developer circulating portion are used to utilize the bulk fluctuation of the developer depending on the toner concentration, A technique for optimizing the toner density is disclosed. In addition, the prior art 5 (Japanese Patent Laid-Open No. 2000-2
No. 75939), a developer carrying member, a restricting member for restricting the amount of developer on the developer carrying member, a developer accumulating portion for accumulating the developer blocked by the restricting member, and the developer. A toner replenishing port, which is a space communicating with the retaining part, and a toner accommodating part adjacent to the developer retaining part via the toner replenishing port, and a toner stirring member provided in the toner replenishing port to stabilize the toner in the developer. There is disclosed a technology for supplying toner in a specific manner.

[0008]

However, in the prior arts 1 to 3, the toner take-in method supplies the toner by bringing the toner into contact with the developer layer on the developer carrying member (or the developing sleeve). Therefore, there are the following technical problems. For example, in the prior art 1, it may certainly be possible to easily adjust the toner density. However, if the developer layer on the developing sleeve is thick,
It may take time for the supplied toner to uniformly diffuse and disperse in the developer, and it may not be possible to stably stir and supply the toner against a sudden change in the toner consumption amount, and it may become impossible to maintain the background and maintain the density. There is.

Also in the prior art 2, the toner is diffused by the circulation of the developer in order to make the toner density uniform, but it takes some time until the toner becomes uniform as a whole. In some cases, the responsiveness of switching between the toner intake and the stop operation may be slow with respect to a rapid change in toner consumption (image density change). If the responsiveness is slow, when the toner consumption amount abruptly increases on the toner consumption side, the toner density decreases, and it is not possible to secure a high image area density, and the image density may become low. Further, when the toner consumption amount is drastically reduced, the toner density is increased, and there is a possibility that the background is stained and the density is excessive.

Further, in the prior art 3, although the response of taking in the toner is improved to some extent, there is a possibility that the uniform dispersion of the toner becomes insufficient.
In other words, the layer-regulated developer is carried to the developing section by the developer carrier and conveyed again into the developing device, comes into contact with the toner in the toner supply section and takes in the toner, and returns to the developer accommodating section, but the layer is regulated. Since the developer layer is strongly attracted to the developer carrier by magnetic force, replacement with the developer in the developer accommodating portion becomes insufficient. For this reason, triboelectric charging due to stirring of the taken-in toner and carrier is not sufficient, and when forming an image such as a halftone, it is easy to cause muddy density unevenness. In any case, when the toner concentration is lowered and the toner is taken in, the toner is directly supplied to the developer layer on the developer carrier, and the supplied toner is conveyed again to the developing unit without being sufficiently stirred. There is a high probability that unevenness in density will occur more easily.

Further, in the prior art 4, a toner replenishing passage formed as a developer circulating portion for optimizing the toner concentration is provided between the developer carrying member and the toner accommodating portion. Since the stirring member is provided in the above, it operates as follows. That is, for example, if the toner concentration in the developer is within an appropriate range, a developer retention portion is formed in the toner replenishing path to prevent the toner from being taken in when the developer and the toner are in contact with each other. On the other hand, when the toner is consumed and the toner concentration in the developer is out of the proper range, the bulk of the developer is reduced to reduce the developer retention portion, and the toner is taken into the developer circulation portion by that amount. Then, the bulk of the developer is gradually increased, the developer retaining portion is formed again, and the toner intake is interrupted. At this time, the agitating member keeps the developer circulating portion uniformly and vigorously, prevents the bridge from being formed in the developer retaining portion, and further, the developer is locally consumed. prevent.

In the prior art 4, although there is a device to uniformly take in the toner to the developer carrying member, the toner is consumed and the developing formed again between the first regulating member and the second regulating member. When the toner concentration in the developer in the developer storage portion is out of the appropriate range, the volume of the developer is reduced to reduce the developer retention portion at the entrance of the toner replenishment path, and the toner is placed in front of the second regulation member. It is taken into the developer circulating portion formed by providing a space. Then, when the bulk of the developer is gradually increased, the developer retaining portion is formed again to interrupt the toner intake. As described above, the developer in the developer containing portion and the developer in the developer circulating portion are substantially separated from each other by the second regulating member, and when rapid toner consumption occurs, there is a fear that the toner take-in responsiveness deteriorates. There is Further, in Prior Art 5, since the toner is agitated at the toner replenishing port that connects the developer accumulating portion and the toner accommodating portion, it is easy to supply the toner facing the developer accumulating portion. There is a technical problem that the toner is not rapidly taken in with respect to the change in the toner concentration in the staying portion, and the toner take-in responsiveness is likely to be insufficient with respect to a rapid toner consumption.

The present invention has been made in order to solve the above technical problems, and can stabilize the autonomous control of toner concentration and charge in the developer, and further, uniform development without density unevenness. The present invention provides a developing device capable of obtaining excellent properties and an image forming apparatus using the developing device.

[0014]

That is, according to the present invention, as shown in FIG. 1, a magnetic field generating means is provided inside and a toner T and a magnetic carrier C (see FIGS. 2 and 3) are included. A developer carrying member 1 for carrying and carrying the component developer G, a regulating member 2 for regulating the amount of developer carried on the developer carrying member 1, and a regulating member 2 adjacent to the developer carrying member 1 and
And a toner accommodating portion 3 for accommodating the developer G on the upstream side of the toner accommodating portion, and a toner accommodating portion for communicating with the developer carrier 1 through the developer accommodating portion 3 and accommodating the toner T in a supplyable manner Section 4 and the toner accommodating portion provided in the developer accommodating portion 3 and rotating in contact with or in proximity to the developer carrier 1 and applying a rotational force to the developer G in the developer accommodating portion 3. Part 4
Rotating member 5 for taking in toner from the developer container 3
And are provided.

In such a technical means, the developer carrying member 1 may be appropriately selected as long as it has a magnetic field generating means inside and carries and conveys the two-component developer G. In many cases, a magnet roll mode including a rotatable non-magnetic sleeve and a magnet member fixedly arranged in the sleeve is used. Further, the regulation member 2 is
If the amount of developer on the developer carrying member 1 is regulated,
The blades, rolls, etc. may be appropriately selected, and the layout thereof may be arbitrarily selected.

Further, the developer container 3 and the toner container 4 may have any positional relationship as long as they communicate with each other.
However, the toner accommodating portion 4 is required to be able to supply the toner, and the toner accommodating portion 4 is not limited to the mode in which the toner supplying member is provided inside, and the toner accommodating portion 4 is disposed above the developer accommodating portion 3, It also includes a mode in which the toner is moved downward by its own weight. In this case, since the toner and the carrier have different specific gravities, the toner floats upward against gravity. For this reason, particularly in the case of non-magnetic property, an appropriate pressing pressure from the toner accommodating portion 4 is required to bring the toner into contact with and take in the developer. When the pressing pressure is not sufficient, the toner is accumulated on the inner wall of the developing device by its own weight due to gravity, and the contact with the developer is unstable. On the other hand, when the pressing pressure is too strong, toner solidification called blocking occurs, which causes toner supply inhibition and image quality abnormality due to poor dispersion in the developer.

Furthermore, it is necessary that the toner accommodating portion 4 is "provided in communication with the developer carrying member 1 through the developer accommodating portion 3", which means that the toner accommodating portion 4 carries the developer. It means that the developer accommodating portion 3 is not adjacent to the body 1 and is interposed therebetween. As a result, the toner T in the toner accommodating portion 4 does not directly contact the developer G in the immediate vicinity on the developer accommodating portion 1, and the developer accommodating portion 1 does not pass through the developer G in the developer accommodating portion 3. Supplied to the side. In this case, since the rotating member 5 is disposed in the developer accommodating portion 3, the toner T in the toner accommodating portion 4 comes into contact with the developer G in the vicinity of the rotating member 5 and the developer is conveyed by the rotating member 5. The toner T is taken in along the conveyance direction of the rotating member 5 by force.

As the rotating member 5, a roll, a brush, a paddle or the like may be appropriately selected as long as it can convey the developer G in the vicinity in the rotating direction. However, from the viewpoint of preventing banding, which is an image defect, for example, the rotating member is preferably in a roll shape. The function of the rotating member 5 is to convey the developer G in the vicinity of the rotating member 5 in the rotating direction. However, the developer G changes its flow behavior in accordance with the toner concentration, and the change of this flow behavior is caused. By utilizing this, the toner T which comes into contact with the developer G is taken in.

Further, as a preferred embodiment of the rotating member 5, there is an embodiment in which the rotating member 5 has magnetism, and typically a magnetic roll (preferably using a soft magnetic member), Also includes magnetic brush and magnetic huddle. When such a magnetic rotating member 5 is used, the magnetic rotating member 5 is magnetized by the magnetic field generating means in the developer carrying member 1, and the rotation of the developer G by the carrier chain is further promoted as the magnetic rotating member 5 rotates. Can be made. As a result, the rotational conveyance behavior of the developer G can be made more active.

As another preferable mode of the rotating member 5, there is a magnet roll having a rotatable non-magnetic sleeve and a magnet member fixedly arranged in the sleeve. In this aspect, the rotating member 5
Due to the magnetization of the developer carrier 1, the interaction between the magnetic field from the magnetic field generating means of the developer carrier 1 and the magnetic field from the rotating member 5 promotes the rotation of the developer G by the carrier chain as the rotating member 5 rotates. Can be made.

Although the structure of the toner containing portion 4 may be appropriately selected, the toner containing portion 4 is preferable in a mode in which the toner containing portion 4 and the developer containing portion 3 are juxtaposed in substantially the same horizontal position. As an aspect, the toner storage unit 4
In order to supply the toner from the developer container 3 to the developer container 3,
An element for sending out the contained toner is usually required, and for example, it is preferable to dispose a pressing and conveying member for pressing the toner toward the developer accommodating section 3 in the toner accommodating section 4.

Further, the rotating direction of the rotating member 5 may be appropriately selected, but from the viewpoint of ensuring the accumulation state of the developer G in the developer accommodating portion 3, the surface moving direction of the rotating member 5 is secured. Is preferably in the same direction as the surface moving direction of the developer carrying member 1 at the facing portion of the developer carrying member 1.

As a preferred embodiment of the developer accommodating portion 3, it is preferable to provide an auxiliary regulation member 6 for regulating the amount of the developer G conveyed by the rotating member 5. The auxiliary regulation member 6 facilitates formation of a developer pool in the developer accommodating portion 3 and the developer carrying member 1 and the rotating member 5.
And various functions of preventing developer jamming between the developer and the developer and avoiding a situation in which the uncharged toner is immediately conveyed to the developer carrier 1. Further, as a preferred layout of the auxiliary regulation member 6, the gap between the rotary member 5 and the auxiliary regulation member 6 is set to be smaller than the gap between the developer carrying member 1 and the rotary member 5. preferable.
As described above, the size relationship of the gap is preferable for more reliably forming the developer pool in the developer containing portion 3.

As a preferred embodiment when the rotary member 5 is a roll-shaped member, it is preferable that the surface of the roll-shaped member is roughened. "Roughening" here
Any of various methods such as sand blasting may be used, and by roughening the surface, it is possible to suppress slippage of the developer on the surface portion and ensure the transportability of the developer. Further, from the viewpoint of improving the toner supply property to the developer carrying member 1, and from the toner fixation of the rotating member 5, the rotating member 5 is biased in the direction in which the toner is transferred to the developer carrying member 1 side. Is preferably applied. Furthermore, as the behavior of the developer G in the developer containing portion 3,
In addition to the rotational conveyance of the developer G by the rotating member 5, there is a behavior associated with the scraping of the developer G by the regulating member 2, but the developer G in the developer accommodating portion 3 is accompanied by the latter developer G behavior.
It is preferable to provide a damming member at a position adjacent to the regulating member 2 of the developer accommodating portion 3 so as not to mix with the toner T of the toner accommodating portion 4. Particularly, for example, the regulation member 2
The behavior of the developer G scraped off by the
Under conditions where excessive toner uptake into the
A portion of the developer accommodating portion 3 adjacent to the regulating member 2 is provided with a damming member facing the rotating member 5.
It is preferable to suppress the excessive intake of toner based on the behavior of the developer scraped off by.

The present invention is not limited to the developing device described above, but also applies to the image forming apparatus. In this case, the present invention is directed to the image carrier 7 and the electrostatic latent image Z on the image carrier 7.
In the image forming apparatus provided with the developing device 8 for converting the above into a visible image, the above-described developing device 8 may be used as the developing device 8.

Next, the operating principle of the developing device according to the present invention will be described with reference to FIGS. Now, as shown in FIG. 2A, when the toner concentration TC in the developer pool near the rotating member 5 (for example, the magnetic roll or the magnet roll) is high, the magnetic permeability is lowered and the carrier chain CC is shortened. At this time, the developer G near the rotating member 5 is conveyed / stirred by the rotating force of the rotating member 5, but the layer thickness of the conveyed / stirred developer becomes small. That is, in the carrier chain CC, as shown in FIG.
Serves as a roller, and the shearing force is difficult to be transmitted, so that the developer layer near the rotating member 5 (the developer layer located on the inner side as indicated by m in FIG. 3) flows, but on the outer side of this fluidized layer G1. The developer layer is not affected by the magnetic force and is not transported. As a result, the developer G in the vicinity of the toner accommodating portion 4 becomes stagnant and the immovable layer G
2, the toner is not taken in even if the developer G and the toner T are in contact with each other. Further, when the toner concentration TC is high, the volume of the developer G is increased due to the increase of the bulk density of the developer G, and the space near the developer pool is filled with the developer G, which also helps the supply of the toner T. There is.

On the other hand, when the toner concentration TC in the developer pool near the rotating member 5 is low, as shown in FIG.
The magnetic permeability of the developer G increases and the carrier chain CC becomes longer. At this time, the developer G in the vicinity of the rotating member 5 is conveyed / stirred by the rotating force of the rotating member 5, but the layer thickness of the developer G conveyed / stirred becomes larger than that in the above case. That is, in the carrier chain CC, as shown in FIG. 4, since the toner T between the carriers C is small, the role as a roller is weak and the shearing force is easily transmitted between the carriers C. Therefore, the developer layer flows not only in the vicinity of the rotating member 5 but also to a portion separated from the rotating member 5 to some extent as shown by m in FIG. Here, according to the toner concentration of the developer G, the fluidized layer G1 extends to the interface between the developer G and the toner T, and
The developer G near the toner containing portion 4 shown in FIG.
The toner T that flows in the rotation direction of and contacts the developer G is taken into the developer. The developer layer outside the fluidized bed G1 is the immobile layer G2. Further, the volume density of the developer G is reduced due to the decrease in the bulk density of the developer G, the space near the developer reservoir is vacant, the toner T is supplied and filled in the vacant space, and the effect that the toner T is easily taken in is also assisted. . The toner concentration of the developer G is autonomously controlled by the above mechanism.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the accompanying drawings. First Embodiment FIG. 5 shows the first embodiment of the image forming apparatus to which the present invention is applied.
FIG. In the figure, the image forming apparatus is
For example, an electrophotographic system is adopted, and includes a photoconductor drum 20 and a developing device 30 that visualizes the electrostatic latent image formed on the photoconductor drum 20.

In the present embodiment, the developing device 30 is
As shown in FIGS. 5 and 6, there is a developing housing 31 that opens toward the photoconductor drum 20, and a developing roll 32 is arranged facing the opening of the developing housing 31. A regulating member 33 for regulating the layer thickness of the two-component developer G on the developing roll 32 is provided at the edge, and the developer G is accommodated in a portion of the developing housing 31 adjacent to the developing roll 32. Agent container 3
4 and the developing roll 3 through the developer accommodating portion 34.
2 and a toner storage portion 35 that stores toner. In this embodiment, as the toner of the developer G, for example, a non-magnetic toner is used, but a magnetic toner may be used as long as it has a magnetic property different from that of the carrier.

In the present embodiment, the developing roll 32
Is a rotatable non-magnetic sleeve 32, as shown in FIG.
1 and a magnetic pole roll 322 fixedly arranged inside the sleeve 321. The magnetic pole roll 322 has a plurality of magnetic poles (four poles in this example: S1 (developing pole), S2 (conveying pole), N) around the roll body at predetermined angular intervals.
1 (trimming pole) and N 2 (conveying pole) are arranged so that the two-component developer G containing toner and carrier (magnetic powder) is magnetically attached to the outer circumference of the developing roll 32. There is. Incidentally, the magnetic pole configuration is arbitrary, and a repulsive magnetic pole is provided at a portion facing the developer accommodating portion 34, and the developing roller 3
The developer layer on 2 may be once peeled off. Further, a bias power source 323 for applying a predetermined developing bias VB is connected to the sleeve 321.

Further, the regulating member 33 is, for example, SUS30.
It is made of a plate material made of 4 and has a developer G between it and the developing roll 32.
Layer thickness control gap g0 (for example, 300 to 600 μm)
m) are spaced apart. And this regulation member 3
The layout of No. 3 may be appropriately selected, but in the present embodiment, the regulating member 33 is arranged slightly downstream of the trimming pole (N1 in this example).

Further, the developer accommodating portion 34 has a space for accommodating the developer G, and the magnetic roll 4 is provided in a portion of the developer accommodating portion 34 which is close to (or in contact with) the developing roll 32.
0 is rotatably arranged. Further, in the present embodiment, the bottom shape of the developer accommodating portion 34 has a curved shape along the developing roll 32 and the magnetic roll 40, and the developing roll 32 and the magnetic roll 40 have a predetermined gap between them. The agent transportation path is secured.

In particular, in this embodiment, the magnetic roll 40
Is a roll using a soft magnetic material (for example, SUM, SUS430, etc.), and has a surface roughness of, for example, Rz10 to 30.
The surface is roughened to about μm (Rz 20 μm in this example). The magnetic roll 40 has a predetermined gap g1 (e.g., 0.8-1..g.) At a portion facing the transport pole S2 located substantially opposite to the developing pole S1 of the developing roll 32.
2 mm) apart from each other, and the rotational movement direction of the magnetic roll 40 is set to be the same as the rotational movement direction of the developing roll 32 at the facing portion of the developing roll 32 (more precisely, the sleeve 321). ing.

Further, in the present embodiment, an auxiliary regulating member 50 made of a plate material made of SUS304, for example, is attached to the bottom of the developer accommodating portion 34 on the side opposite to the developing roll 32 near the magnetic roll 40. Therefore, the gap g2 (for example, 0.4 to 0.8 mm) between the magnetic roll 40 and the auxiliary regulation member 50 is set narrower than the gap g1. Furthermore, a bias power source 4 for applying a predetermined bias to the magnetic roll 40 as needed.
1 is connected. The bias power source 41 here means a bias that forms an electric field that transfers toner to the developing roll 32 side.

Further, the toner accommodating portion 35 has an agitator 351 (see FIG. 5) for agitating and conveying the accommodating toner, and the agitator 351 is, for example, a rotating body provided with an elastic film. The toner is swept out along the bottom wall surface of 35. The bottom shape of the toner storage portion 35 is the agitator 35.
1 has a curved shape along the movement and rotation locus of 1, and a communication port 36 is provided at a connection portion between the developer accommodating portion 34 and the toner accommodating portion 35, and a lower end edge of the communication port 36 has an agitator 351. It is set slightly lower than the center position of. On the other hand, a blocking block 37 is provided near the upper edge of the communication port 36 to effectively prevent the situation where the developer G in the developer accommodating portion 34 enters the toner accommodating portion 35 side.

Further, the drive system for the developing roll 32, the magnetic roll 40, and the agitator 351 may be appropriately selected. For example, as shown in FIG.
2 and the agitator 351 are driven by a first drive motor 61 and a drive transmission system (transmission belt, pulley, gear, etc.) 62, while the magnetic roll 40 drives the second drive motor 63 and the drive transmission. System (transmission belt, pulley,
64).

Next, the operation of the image forming apparatus according to this embodiment will be described focusing on the developing device. Now, the developing roll 32
Assuming that the toner concentration TC of the upper developer layer is sufficiently high, when the developer G returns to the developing housing 31 as the developing roll 32 rotates, the developer G in the developer accommodating portion 34 is Since the toner concentration TC is high, the magnetic permeability is low, and the developer behavior (poor fluidity) shown in FIGS. 2A and 3 is exhibited. At this time, the magnetic roll 40 is the developing roll 3
It is magnetized by the magnetic field generated by the magnetic pole roll 322 in the magnetic field roller 2, and the developer G is magnetically adsorbed on the surface of the magnetic pole roll 322, and the developer G is conveyed in the rotation direction of the magnetic roll 40. Therefore, the developer G located in the vicinity of the magnetic roll 40 flows as the fluidized layer G1, but many developer layers outside the fluidized layer G1 do not move as the immovable layer G2 and a developer pool is formed. Therefore, the toner from the toner storage portion 35 is not taken into the developer G but stays in the developer reservoir.

On the other hand, assuming that the toner is rapidly consumed, the toner concentration TC of the developer layer on the developing roll 32 is
Therefore, when the developer G returns to the developing housing 31 due to the rotation of the developing roller 32, the developer G in the developer accommodating portion 34 has a low toner concentration TC, and therefore has a high magnetic permeability. The developer behavior (good fluidity) shown in FIGS. 2B and 4 is shown. At this time, the magnetic roll 40 is magnetized by the magnetic field of the magnetic pole roll 322 in the developing roll 32, the developer G is magnetically adsorbed on the surface thereof, and the developer G is conveyed in the rotating direction of the magnetic roll 40. Therefore, many developer layers up to the part away from the magnetic roll 40 flow as the fluidized layer G1, and the immobile layer G2 is not formed on the outer side thereof. Therefore, a large rotational conveyance force acts on the developer G around the magnetic roll 40, so that the toner from the toner storage unit 35 is sequentially taken into the developer G having the rotational conveyance behavior, and the magnetic roll 40 is thus introduced. The toner concentration in the developer G conveyed by the rotation of increases immediately.

The developer G with the toner thus taken in
Is forcibly moved in accordance with the rotation of the magnetic roll 40, but the toner T is sequentially diffused in the developer G having such a rotational conveyance behavior, and is sufficiently charged with the movement of the carrier chain, so that the development is performed. It is conveyed to the roll 32 side.
Therefore, the toner T supplied from the toner storage unit 35 is not immediately conveyed to the developing roll 32 side, but is moved to the developing roll 32 side while being sufficiently charged. Therefore, the toner concentration of the developer layer on the developing roll 32 is immediately and autonomously controlled.

In particular, in this embodiment, the magnetic roll 40
The auxiliary regulation member 50 is arranged in the above position, and the layer of the developer G conveyed on the magnetic roll 40 is regulated by the auxiliary regulation member 50. Therefore, the regulation member (first regulation member) 33
The developer G scraped off by and the developer G scraped off by the auxiliary restricting member 50 (second restricting member) form a pool, and the toner supplied from the communication port 36 of the toner accommodating portion 35 is supplied. Contact T.

As described above, the auxiliary regulation member 50 effectively forms the developer pool, and also has an effect of suppressing the jamming of the developer between the developing roll 32 and the magnetic roll 40 and the deterioration of the developer, and the magnetic roll 40. The developer in the vicinity is conveyed by the rotation of the magnetic roll 40, but the excessive toner is scraped off by regulating the rising of the developer on the magnetic roll 40, so the toner is not immediately conveyed to the developing roll 32. In this way, the effect of preventing uneven image quality due to uncharged toner is exerted.

Modified Embodiment In the above embodiment, the magnetic roll 40 is used. However, the present invention is not limited to this. For example, as shown in FIG. 8, a rotatable sleeve 81 and this sleeve 8 can be used.
Magnetic pole roll (magnet member) 82 fixedly disposed in
You may make it use the magnet roll 80 provided with.
In this embodiment, the number of magnetic poles and the magnetic pole arrangement of the magnetic pole roll 82 may be appropriately selected, but for example, two poles (S, N in this example) may be arranged. Also,
A bias power source 8 is provided for providing an auxiliary regulating member 50 in the vicinity of the magnet roll 80, roughening the surface of the sleeve 81, and applying a predetermined bias to the sleeve 81.
No. 3 may be appropriately selected, for example, provided as necessary.

According to this aspect, substantially the same operation as that of the first embodiment is achieved, but the magnet roll 80 is different from that of the first embodiment.
The magnet roll 8 is originally magnetized, and the influence of the magnetic field from the developing roll 32 is superimposed.
The holding and transporting force of the developer G by 0 is further strengthened as compared with the first embodiment, and the rotational transporting behavior of the developer G accompanying the rotation of the magnet roll 80 appears more strongly. Therefore, the toner concentration in the developer and the autonomous control of the charging are more reliably performed.

Second Embodiment FIG. 9 is an explanatory diagram showing an image forming apparatus according to the second embodiment. In the figure, the image forming apparatus is the same as that of the first embodiment.
(However, the shape of the regulating member 33 and the developing roll 32
The magnetic pole layout is slightly different from that of the first embodiment. ), The developing device 30 has a blocking block 38 different from that of the first embodiment.
The blocking block 38 is provided adjacent to the regulation member 33, but has a protruding portion 381 that faces the magnetic roll 40 while maintaining a predetermined gap therebetween. The same components as those of the first embodiment are designated by the same reference numerals as those of the first embodiment, and detailed description thereof will be omitted here.

According to the present embodiment, the developer accommodating portion 34
Focusing on the behavior of the developer G in the above, the developer G rotates and moves in accordance with the rotation of the magnetic roll 40, and
The developer G moves due to the scraping of the developer G. At this time, the blocking block 38 blocks the developer G scraped off by the regulating member 33 from moving toward the toner containing portion 35 side, and the developer G in the developer containing portion 34 becomes toner. The situation of being mixed in the accommodation portion 35 is effectively avoided. Also,
The protrusion 381 of the blocking block 38 is provided on the regulation member 33.
Thus, the developer G scraped off is stopped from moving toward the magnetic roll 40. Therefore, the behavior of the developer G in the peripheral portion of the magnetic roll 40 is not unnecessarily activated due to the influence of the behavior of the developer G caused by the scraping of the regulation member 33, and the toner from the toner accommodating portion 35 is prevented. Is not excessively taken into the developer G in the developer accommodating portion 34, and the toner take-in characteristic is extremely stable.

[0046]

EXAMPLE In this example, the developing device according to the first embodiment is embodied and the toner take-in characteristics are measured. The test conditions of this example are as follows. Two-component developer G: The average particle size of the carrier was 35 μm, the amount used was 40 g, the magnetic toner was 10 μm, and the average particle size of the toner was 10 μm. Transported developer amount MO
S is 45 to 55 mg / cm ² . The developing roller 32 has a 4-pole structure and has the magnetic force pattern shown in FIG. MSA (Magnet Set Angle) is +
It is 0 °. The peripheral speed is 416 rpm. -Regulating member 33: T / G (trimming gap) is 0.
25-0.3 mm-Magnetic roll 40: Material SUS, outer diameter φ7 mm, and further subjected to surface roughening treatment of Rz 10-15 μm by sandblast # 60. The peripheral speed is 916 rpm.

Under the test conditions as described above, the developing device according to the embodiment was operated and the temporal change of the toner density was examined. As a result, the toner take-in characteristics shown in FIG. 11 were obtained. According to the figure, it is understood that when the developing device according to the embodiment is operated, the predetermined toner concentration TC is reached immediately after the operation is started (1 minute). This means that even if the toner is rapidly consumed and the toner concentration is lowered, the toner is immediately replenished and the toner concentration TC returns to a predetermined level, which supports the performance of the first embodiment. Is.

[0048]

As described above, according to the present invention, the developer accommodating portion is provided adjacent to the developer carrying member and on the upstream side of the regulating member, and the developer carrying portion is carried through the developer accommodating portion. A toner accommodating portion communicating with the body is provided, and the toner from the toner accommodating portion is rotated in the developer accommodating portion in a state of rotating in contact with or close to the developer carrier and imparting a rotational force to the developer in the developer accommodating portion. Since the rotary member for taking in is provided, the following basic effects are achieved. First, it is possible to stabilize the autonomous control of toner concentration in the developer and charging. Specifically, even if there is rapid toner consumption, the toner supply by the rotating member has a high responsiveness, so that the toner concentration of the developer layer on the developer carrier can be controlled quickly and accurately. Further, toner is supplied to the developer in the vicinity of the rotating member and the toner is positively dispersed in the developer by the rotating force of the rotating member. The frictional electrification of the toner is sufficiently performed by the rotational vortex behavior of the developer by the member, and accordingly, the electrified state suitable for image formation is obtained. Secondly, uniform developability without density unevenness can be obtained. That is, since the supplied toner is once supplied into the developer having the rotational vortex behavior by the rotating member, the raw toner having a poor charging does not directly ride on the developer layer on the developer carrier. Further, since the toner in the vicinity of the developer accommodating portion is taken in while being broken by the rotating member, the diffusion of the toner into the developer becomes good.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a developing device according to the present invention and an image forming apparatus using the same.

FIG. 2A is an explanatory view showing the behavior of the developer around the rotating member of the developing device when the toner concentration is low and the magnetic permeability is high, and FIG. 2B is the developing device when the toner concentration is high and the magnetic permeability is low. FIG. 6 is an explanatory diagram showing the behavior of the developer around the rotating member of FIG. FIG. 3 is an explanatory diagram showing the overall configuration of the image forming apparatus according to the first embodiment.

FIG. 3 is an enlarged explanatory diagram showing the behavior of the developer around the rotating member when the toner concentration is high and the fluidity is poor.

FIG. 4 is an enlarged explanatory diagram showing the behavior of the developer around the rotating member in a state where the toner concentration is low and the fluidity is good.

FIG. 5 is an explanatory diagram showing an overall configuration of the image forming apparatus according to the first embodiment.

FIG. 6 is an enlarged view of a main part thereof.

FIG. 7 is an explanatory diagram showing a drive system of the developing device in the present embodiment.

FIG. 8 is an explanatory diagram showing a modification of the developing device according to the present embodiment.

FIG. 9 is an explanatory diagram showing an overall configuration of an image forming apparatus according to a second embodiment.

FIG. 10 is an explanatory diagram showing an example of a magnetic pole pattern of a developing roll used in the examples.

FIG. 11 is an explanatory diagram showing toner intake characteristics of the developing device according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Developer carrying body, 2 ... Regulator member, 3 ... Developer accommodating part,
4 ... Toner container, 5 ... Rotating member, 6 ... Auxiliary regulating member,
7 ... Image carrier, 8 ... Developing device, G ... Two-component developer, Z ...
Electrostatic latent image

Claims (11)

[Claims] 1. A developer carrying body having a magnetic field generating means therein and carrying and carrying a two-component developer containing toner and magnetic carrier, and an amount of the developer carried on the developer carrying body. A regulating member for regulating, a developer accommodating portion which adjoins the developer carrier and accommodates a developer on the upstream side of the regulating member, and communicates with the developer carrier through the developer accommodating portion. A toner accommodating portion which is provided and accommodates toner so as to be able to be supplied; And a rotating member that takes in the toner from the toner containing portion into the developer containing portion in the opened state. 2. The developing device according to claim 1, wherein: The developing device is characterized in that the rotating member has magnetism. 3. The developing device according to claim 1, wherein the rotating member is a magnet roll including a rotatable non-magnetic sleeve and a magnet member fixedly arranged in the sleeve. And developing device. 4. The developing device according to claim 1, wherein the developer accommodating portion and the toner accommodating portion are arranged side by side at substantially the same horizontal position, the toner accommodating portion is provided with toner toward the developer accommodating portion. A developing device having a pressing and conveying member for pressing the developing device. 5. The developing device according to claim 1, wherein the surface moving direction of the rotating member is the same as the surface moving direction of the developer carrying member at the facing portion of the developer carrying member. apparatus. 6. The developing device according to claim 1, further comprising an auxiliary restricting member that restricts a conveyance amount of the developer conveyed by the rotating member. 7. The developing device according to claim 6, wherein a gap between the rotating member and the auxiliary regulating member is set smaller than a gap between the developer carrying member and the rotating member. Developing device. 8. The developing device according to claim 1, wherein the rotating member is a roll-shaped member, and the surface thereof is roughened. 9. The developing device according to claim 1, wherein a bias is applied to the rotating member in a direction in which the toner is transferred to the developer carrying member side. 10. The developing device according to claim 1, further comprising a damming member facing the rotating member, at a portion of the developer accommodating portion adjacent to the regulating member. 11. An image forming apparatus comprising an image carrier and a developing device for visualizing an electrostatic latent image on the image carrier, wherein the developing device is any one of claims 1 to 9. An image forming apparatus using the developing device described above.