JPH09325596A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device with wide latitude in setting a developer control condition and capable of carrying only satisfactorily and electrostatically charged toner into a developing area. SOLUTION: A permanent magnet 6 is rotatably arranged near non-magnetic developer amount control member 7 so that the line of a magnetic force may extend into the developer amount control area. Besides, a carrying magnetic force into a developer container 3 is formed for at least the magnetic toner lying near the surface of the developer amount control member 7 in the developer amount control area. Besides, a member for adjusting the shape of a magnetic field 8 of a magnetic body for forming the magnetic field in cooperation with a moving magnetic field is arranged in a developing sleeve 1a and near the developer amount control area, then, the variation of a magnetic flux density near the developing sleeve 1a in the developer amount control area is reduced. And also, the magnetic flux density of the magnetic field of the permanent magnet 6 formed between the magnet 6 and the member 8 for adjusting the shape of the magnetic field is constituted so that it may be made higher as it goes from the developing sleeve 1a toward the developer amount control member 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device used in an image forming apparatus such as an electrophotographic device and an electrostatic recording device, and in particular, a magnetic one-component developer and a developer containing a toner and a magnetic carrier are used. The present invention relates to a developing device.

[0002]

2. Description of the Related Art Conventionally, as a developing method using a magnetic one-component developer, in JP-A-54-43036, a magnetic toner is applied very thinly on a sleeve, the toner is triboelectrified, and then the magnetic field is applied. Under the action of (1), the electrostatic image is brought into close proximity to the electrostatic image, and the electrostatic image is opposed to the electrostatic image, and the image is developed.

Further, in Japanese Laid-Open Patent Publication No. 54-43037, as a method of applying the magnetic toner extremely thinly, a regulating member formed of a magnetic member is operated under the action of a magnetic field of a fixed magnet arranged inside the sleeve. A method is disclosed in which the magnetic toner is applied very thinly on the sleeve so as to be extremely close to the sleeve and face each other without coming into contact with the sleeve.

An example of a developing device using this method is shown in FIG.
Shown in In the developing device shown in FIG. 10, a magnetic toner T, which is a magnetic one-component developer, is housed in the developing container 3, and an opening facing the photosensitive drum 15 as an electrostatic latent image carrier is provided in the developing container 3. A developing sleeve 1a as a developer carrying member is rotatably installed in the section in the direction of the arrow. The developing sleeve 1a is made of a non-magnetic member, and the magnet 1b is non-rotatably installed inside. Further, a developer carrying member 4 is installed at the back of the developing container 3,
The magnetic toner T inside is stirred and conveyed to the developing sleeve 1a side. Further, a magnetic blade 2 as a developer amount regulating member is installed above the developing sleeve 1a at the opening of the developing container 3, and the magnet 1 in the developing sleeve 1a is installed.
One of the magnetic poles b of b and the magnetic blade 2 are opposed to each other, thereby forming a developer amount regulation region. The magnetic blade 2 is arranged such that the distance between the magnetic blade 2 and the developing sleeve 1a is a constant value W. Generally, the distance W between the magnetic blade 2 and the developing sleeve 1a is 100.
It is often set within the range of μm to 1 mm.

Magnetic toner T contained in the developing container 3
Is carried on the developing sleeve 1a by the magnet 1b,
By the rotation of the developing sleeve 1a, the developing sleeve 1a is conveyed toward a developing area facing the photosensitive drum 15. During the conveyance, the developing blade 1a is regulated by the magnetic blade 2 in the developer amount regulating area to form a thin layer on the developing sleeve 1a. It is applied thinly. As shown in FIG. 12, the thin toner layer has a thickness that passes between the developing sleeve 1 a and the magnetic blade 2.
It is determined by the position of the cut line L along substantially parallel to the surface of a. The cut line L will be further described later.

However, since the copied image by the above-mentioned magnetic one-component system is a system in which it is developed under the action of a magnetic field as described above, the toner is chained during development due to the influence of the magnetic field (generally, "brush"). The resolution in the horizontal direction of the image tends to be worse than that in the vertical direction.For example, the phenomenon of poor resolution due to the protrusion of the spikes in the non-image area in the latter half of the developed image occurs. Tends to be easy. Further, when trying to develop a solid black image, it is difficult to close-pack the ears, and due to the way the ears overlap, a gap is created in the developed solid black image, and a uniform solid black image is obtained. There was a tendency not to be able to.

According to the investigation by the present inventors, FIG.
As shown in (a) and (b), the length of the above-mentioned ears is inversely proportional to the charge charge of the toner on the sleeve, and the toner is not charged to a desired charge polarity, that is, the toner of the opposite polarity. It was found to be proportional to the amount of. That is, when the toners are charged to the same polarity, an electric repulsive force acts between the toners, and when the charged electric charge is large, the electric repulsive force exceeds the magnetic coupling force, so that the ears are formed. It is supposed to be difficult. Therefore, in order to eliminate the effect of the spikes in the presence of a magnetic field, the charge charge of the toner is stably controlled,
That is, it has been found that it is necessary to make at least uniform polarity or increase the amount of charge.

Further, according to the investigation by the present inventors, when the magnetic toner T passes between the developing sleeve 1a and the magnetic blade 2, the magnetic toner T is charged, and at the charge applying portion. It was found that the toner transportation and behavior are as follows.

As shown in FIG. 11, two planes perpendicular to the straight line connecting the developing sleeve 1a and the magnetic blade 2 are considered, and the surface close to the magnetic blade 2 is S1 and the surface close to the developing sleeve 1a is S2. Generally, the width of the magnetic blade 2 (the length in the direction along the circumferential direction of the developing sleeve 1a) is made narrower than the width of the magnetic pole N of the permanent magnet 1b, so that the magnetic field from the magnetic pole N of the permanent magnet 1b. Considering the respective magnetic flux densities on the S1 surface and the S2 surface, the magnetic flux density on the S1 surface is S
It is larger than the magnetic flux density on the two surfaces. Therefore, the magnetic toner T carried on the developing sleeve 1a is
Between a and the magnetic blade 2, a force in the direction of the arrow in FIG. 11 according to the strength of the magnetization of the magnetic toner, that is, a magnetic force that converges on the magnetic blade 2 is received.

Therefore, the magnetic toner T forms a spike (B state) between the developing sleeve 1a and the magnetic blade 2 and the spike is formed by the magnetic blade 2 as shown in FIG.
To form a brush head toward the developing sleeve 1a.

The magnetic toner T is charged by the developing sleeve 1a and the toner t1 at the tip of the brush formed by the magnetic blade 2 contacting each other, and the toner is charged at the tip. .

Further, the developing sleeve 1a and the magnetic blade 2
It was found that the toner was transported between the following locations.

As described above, the toner t1 at the tip of the brush that comes into contact with the developing sleeve 1a is imparted with a triboelectric charge having a polarity for developing the latent image, so that the developing sleeve 1a is electrostatically reflected. Force works in the direction.

Therefore, the toner t1 at the tip of the spike is attached to the developing sleeve 1a, and a frictional force with the developing sleeve 1a gives a conveying force in the rotating direction of the developing sleeve 1a.

At this time, since a certain amount of cohesive force is exerted between the toner particles, the toner (first toner
The toner t2 of the second layer, which is in contact with the toner (t1) of the layer and immediately above the toner (t2) of the layer, also has a transporting force through the cohesive force.
Similarly, the toner t3 of the third layer above the toner t3 also has a carrying force with the cohesive force interposed.

However, as described above, the magnetic force in the direction of the magnetic blade 2 also acts on the toner between the developing sleeve 1a and the magnetic blade 2. Therefore, when the conveying force applied to the toner overcomes the magnetic force, that is, when the cut line L in FIG. 12 is set at this place, the toner ears are torn at the developing sleeve 1a side with the cut line L as a boundary, and the developing process is performed. The toner remaining on the sleeve 1a is conveyed in the rotation direction of the developing sleeve 1a.

Next, as shown by A in FIG. 12, the toner remaining on the magnetic blade 2 side is not sufficiently given the electric charge, but when the toner pool formed by this residual toner becomes large, the toner is magnetically attracted. The magnetic blade 2 cannot continue to be held, and a toner lump having insufficient charge is separated from the toner reservoir and is conveyed in the rotation direction of the developing sleeve 1a.

The above is the mechanism for imparting and transporting the electric charge and the behavior of the toner when the magnetic toner T passes between the developing sleeve 1a and the magnetic blade 2.

[0019]

However, according to the above-mentioned conventional example, as is clear from the toner behavior of the above-mentioned conventional example and the process of imparting charge to the toner, in the above-mentioned conventional example,
Only the toner in the vicinity of the developing sleeve 1a, that is, the toner t1 of the first layer on the developing sleeve 1a can be charged with sufficient charge, and a part of the toner conveyed by the developing sleeve 1a is necessary. It is occupied by toner that is left uncharged. As a result, conventionally, there have been cases where the development of the toner becomes unstable due to the unstable charging of the toner, so that a stable and good image cannot be obtained.

Further, in JP-A-54-43038, as a method of applying a very thin one-component developer, a regulating member formed of an elastic member is brought into contact with the sleeve to make the toner extremely thin on the sleeve. A method of applying is disclosed.

A developing device using this method is shown in FIG. In the developing device shown in FIG. 14, the regulating member 21 formed of an elastic member is brought into contact with the sleeve 1 and the toner is applied to the sleeve 1 extremely thinly. However, in this configuration, when the contact pressure of the regulating member 21 is high, the rotational load torque of the developing sleeve 1 becomes heavy, and frictional heat is generated at the contact portion. Therefore, particularly when a toner having a low melting point is used. In some cases, toner adheres to the regulation member 21 easily, and when the contact pressure is lowered, toner regulation failure easily occurs, that is, the contact setting condition range of the elasticity regulation member 21 is narrow.

Further, as another method for applying the one-component developer extremely thinly, the method disclosed in Japanese Patent Publication No. 58-90668 and Japanese Patent Publication No. 58-143360, that is, as shown in FIG. The method is known. In FIG. 15, a developing device 30 includes a developing container 33 containing a non-magnetic toner 31 and magnetic particles 32, and a non-magnetic material developing member provided in an opening portion of the developing container 33 facing the photosensitive drum 15. The sleeve 1a, the permanent magnet 1b fixedly arranged inside the non-magnetic sleeve 1a, and the magnetic blade 62 fixed to the developing container 33 and for controlling the layer thickness of the toner supported and conveyed to the photosensitive drum 15 side are provided. The distance between the magnetic blade 62 and the developing sleeve 1a is 2
It is set to about 50 μm.

In the developing device 30 thus constructed, the magnetic particles 32 form a brush 32a along the magnetic field between the magnetic blade 62 and the permanent magnet 1b, and are held in the magnetic field. Here, the non-magnetic toner 31 moves while being dragged by the developing sleeve 1a having a rough surface, and at the same time, charged by friction between the magnetic particles 32 and the developing sleeve 1a, and the magnetic particles 32 and the developing sleeve are reflected by the mirroring force. 1
Although the magnetic particles 32 adhere to a, the magnetic particles 32 cannot move due to the constraint of the magnetic field described above. Therefore, only the non-magnetic toner 31 adhered to the developing sleeve 1a can pass through the brush 32a of the magnetic particles 32, and By rotation, a uniform layer of the non-magnetic toner 31 is formed on the surface of the developing sleeve 1a.

However, in the above-mentioned structure, the magnetic particles are appropriately restrained in terms of regulation of the toner on the developing sleeve and prevention of passage of the magnetic particles between the magnetic blade and the developing sleeve. In addition, it is necessary to form an appropriate circulation state of the magnetic particles in order to supply the toner toward the regulating portion.

Therefore, in the above-mentioned structure, it is necessary to satisfy the contradictory conditions of proper restraint of magnetic particles by the magnetic field and proper circulation, so that the setting latitude is sometimes narrow.

Therefore, it is an object of the present invention to provide a developing device which has a wide setting latitude for the condition for controlling the amount of developer and which can convey only sufficiently charged toner to the developing area. Is.

[0027]

According to a first invention of the present application, the above object is to develop an electrostatic latent image on an electrostatic latent image carrier with a developer containing at least one magnetic particle. And a developer container containing the developer, and a developer container containing the toner on a surface of the developer container, and a developer container for developing the electrostatic latent image from the developer container. A developing device comprising a developer carrying member for carrying a developer and a developer amount controlling means for controlling an application amount of the developer on the developer carrying body, the developer amount controlling means and the developer carrying body. And a magnetic flux of the moving magnetic field in the vicinity of the developer carrier in the developer amount controlling area, which is provided with a means for generating a moving magnetic field that conveys the developer to the inner side of the developing container. Less in the area where the density change is small and in the developer amount regulation area It is accomplished by region where the magnetic flux density increases as well directed from the developer carrying member to the developer amount regulating means direction is formed.

According to the second aspect of the present invention,
In the first aspect of the invention described above, a region where the moving range of the moving magnetic field is narrowed or a region where the moving magnetic field is substantially stationary is formed near the developer carrier in the developer amount regulating region. It is achieved by

Further, according to a third invention of the present application, in the above-mentioned first invention or second invention, the moving magnetic field generating means is rotatably arranged having a plurality of magnetic poles. It is achieved by being a permanent magnet.

Further, according to the fourth invention of the present application,
The above-mentioned object is any one of the above-mentioned first to third inventions, in which the moving magnetic field generating means is disposed on the developer amount regulating means side, and the moving magnetic field generating means is provided near the developer carrier in the developer amount regulating area. This is achieved by disposing a magnetic member that forms a magnetic field in cooperation with the moving magnetic field.

Further, according to a fifth invention of the present application, in the above-mentioned fourth invention, the moving magnetic field generating means arranged on the developer amount regulating means side cooperates with the moving magnetic field. This is achieved by being arranged on the downstream side of the developer carrier in the developer transport direction with respect to the magnetic member that forms the magnetic field.

According to the sixth invention of the present application,
In the fourth or fifth aspect of the invention described above, the magnetic member that cooperates with the moving magnetic field to form a magnetic field is such that the developer amount regulating means and the developer carrying member in the developer amount regulating region are closest to each other. This is achieved by being arranged on the upstream side of the developer carrier in the developer transport direction with respect to the section.

Further, according to the seventh invention of the present application, the above-mentioned object is that in at least one of the first to sixth inventions, at least one of the magnetic particles is a magnetic toner. To be achieved.

According to the eighth invention of the present application,
The above object can be achieved by at least one of the magnetic particles being a magnetic carrier in any one of the first to sixth inventions.

Further, according to a ninth invention of the present application, in the above-mentioned object, in any one of the first invention to the eighth invention, the developer carrier in the developer amount regulating region is the developing device. The force that carries and conveys the toner on the agent carrier is a force that mainly depends on the amount of charge that is imparted to the toner by frictional charging between the toner and the developer carrier. The force of the amount regulating means for regulating the developer on the developer carrier is achieved by being a force that depends on the magnetic force applied to the developer.

That is, in the first aspect of the present invention, due to the magnetic force of the moving magnetic field and the friction with the developer amount regulating means, the developer in the developer amount regulating region is conveyed inward in the developing container. When a force is applied and the developer carrying member rotates, the developer in contact with the developer carrying member is imparted with a charge by frictional charging with the developer carrying member. A force is exerted on the developer in the direction of the developer carrying member due to the mirroring force, and a conveying force in the rotating direction of the developer carrying member is given by the frictional force with the developer carrying member.

Therefore, for the developer in contact with the developer carrying member, the carrying force (F1S) depending on the charge amount of the developer from the developer carrying member and the carrying force (F2S) due to the moving magnetic field. ) Is given as the main force of the carrying force, and the developer not in contact with the developer carrying member also has a cohesive force between the developers, so that the carrying force from the developer carrying member ( F1) and the carrying force (F2) due to the moving magnetic field are given as the main force of the carrying force.

The carrying forces F1S and F1 accompanying the rotation of the developer carrying member and the carrying forces F2 and F2S due to the moving magnetic field.
Between them, there is a magnitude relation of F1S> F1 F2S <F2.

Therefore, in the first invention according to the present application, a region where the change in the magnetic flux density of the moving magnetic field in the developer amount control region near the developer carrying member is small is provided, and the carrying force F2S by the moving magnetic field is provided. Is substantially constant regardless of the location, and a region where the magnetic flux density increases from the developer carrier toward the developer amount controlling means is provided. Therefore, by adjusting the carrying force F2 by the moving magnetic field, In the amount regulation region, the main force for transporting the developer toward the developer carrying body is, with respect to the developer in contact with the developer carrying body,
A region having a force depending on the charge amount of the developer can be present.

Therefore, by satisfying the condition of F1S> F2 ≧ F1, the developer conveyed to the developing area is only the sufficiently charged developer.

In the second invention of the present application, a region in which the moving range of the moving magnetic field is narrowed, or substantially, near the developer carrier in the developer amount regulating region of the first invention. Since we set up an area that will be stationary,
The magnetic flux density of the moving magnetic field in the developer amount control area on the developer carrier is almost constant regardless of the location, and the moving speed of the magnetic force lines in the developer amount control area is developed by the developer amount control means. The agent carrier side is slower. Therefore, the variation in the density of the moving magnetic field is eliminated, the transporting force F2S due to the moving magnetic field is substantially constant regardless of the location, and the moving speed of the magnetic force line near the developer carrying member is slow, so that the developer is carried by the developer carrying member. The time in which the developer is in contact with the developer increases, and the amount of charge of the developer increases.

Further, according to the third invention of the present application, since the moving magnetic field generating means of the first invention or the second invention is a rotatably arranged permanent magnet having a plurality of magnetic poles, it is simple. A suitable moving magnetic field is generated with various configurations.

Further, in the fourth invention according to the present application, the moving magnetic field generating means is arranged on the developer amount regulating means side of any one of the first to third inventions, and the developer amount is increased. Since a magnetic member that cooperates with the moving magnetic field to form a magnetic field is arranged in the vicinity of the developer carrier in the regulated area, a change in the magnetic flux density of the moving magnetic field near the developer carrier in the developer amount regulated area is reduced. It becomes smaller and the carrier force F2S due to the moving magnetic field
Is substantially constant regardless of the location, and by setting the width of the magnetic member, the magnetic flux density is increased in the direction from the developer carrying member to the developer amount regulating means, and the carrying force F2 by carrying by the moving magnetic field is increased. By adjusting, in the developer amount regulation area, the main force that conveys the developer toward the developer carrier with respect to the developer in contact with the developer carrier is the charge amount of the developer. There can be regions of dependent power.

Further, in the fifth invention according to the present application, the moving magnetic field generating means arranged on the developer amount regulating means side of the fourth invention forms a magnetic field in cooperation with the moving magnetic field. Since it is arranged on the downstream side of the developer carrying member in the developer transport direction with respect to the magnetic member, the moving magnetic field generating means and the magnetic member that cooperates with the moving magnetic field to form a magnetic field cooperate with each other. By twisting the magnetic force lines of the magnetic field formed by the above, the magnetic flux density of the magnetic field formed between the moving magnetic field generating means and the magnetic member becomes denser, and in the downstream portion of the developer amount regulation region. Inevitably, there is a magnetic field region in which the magnetic flux density increases from the developer carrier toward the developer amount controlling means. Therefore, the carrying force of the magnetic toner due to the moving magnetic field is increased, so that the latitude of the constitutional conditions for satisfying the relational expression F1S> F2 ≧ F1 is widened.

In the sixth invention according to the present application, the magnetic member that forms the magnetic field in cooperation with the moving magnetic field of the fourth invention or the fifth invention is the developer amount in the developer amount regulation region. Since it is arranged on the upstream side of the developer carrying body in the developer carrying direction with respect to the closest portion between the regulating means and the developer carrying body, the carrying force by the moving magnetic field is at the most downstream side in the developer amount regulating area. Is the largest, and the latitude of the constitution conditions for preventing the passage of the developer at the closest portion is wide. Therefore, only the developer having a stable charge amount is conveyed to the developing area, and a high-quality image can always be stably obtained.

Further, in the seventh invention according to the present application, since at least one of the magnetic particles of any one of the first to sixth inventions is a magnetic toner, a developing device using a one-component developer is provided. In, the high quality image is always obtained stably.

In the eighth invention of the present application, since at least one of the magnetic particles of any one of the first to sixth inventions is a magnetic carrier, a developing device using a two-component developer is provided. In, the high quality image is always obtained stably.

Further, in the ninth invention according to the present application, the developer carrying member is on the developer carrying member in the developer amount regulating region according to any one of the first to eighth inventions. The force for carrying and transporting the developer is a force mainly dependent on the amount of charge that is imparted to the developer by frictional electrification between the developer and the developer carrying member. Since the force of the regulation means for regulating the developer on the developer carrying member depends on the magnetic force applied to the developer, by adjusting the magnetic force, only the developer having a sufficient charge amount can be selected. And then transport.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, the present invention is described as being embodied in, for example, an electrophotographic image forming apparatus as shown in FIG. 9, but the present invention is not limited to this.

In FIG. 9, the electrophotographic image forming apparatus is
A photosensitive drum 15 which is a drum-shaped electrophotographic photosensitive member as an electrostatic latent image carrier is rotatably provided.
5 is uniformly charged by the charger 12, and then the surface of the photosensitive drum 15 is exposed by a scanning light 13 such as a laser based on an information signal to form an electrostatic latent image. The image is visualized as a toner image by the developing device 10. next,
The toner image is transferred onto the transfer paper 16 by the transfer charger 14, and the transfer device 16 is nip-conveyed by the fixing device 17 to fix the toner image on the transfer paper 16. Further, the transfer residual toner on the photosensitive drum 15 is removed by the cleaning device 11.

The above is the image forming process in the image forming apparatus shown in FIG. 9, but in the following description, especially the developing device 1 will be described.
The developing process by 0 will be described.

(First Embodiment) First, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG.
It is sectional drawing which showed this embodiment.

In FIG. 1, a developing device 10 is arranged so as to face a photosensitive drum 15 which is a latent image carrier, and 1a is a non-magnetic metal which is arranged in an opening of a developing container 3 so as to be rotatable in an arrow direction. A developing sleeve as a developer carrying member composed of members, 1b is a permanent magnet disposed inside the developing sleeve 1a, 3 is a developing container, 3a is a developer accommodating chamber, 3b.
Is a toner accommodating chamber, 4a is a conveying member rotatably arranged in the arrow direction for conveying the magnetic toner (not shown) in the developer accommodating chamber 3a toward the developing sleeve 1a, and 4b is the toner accommodating chamber. A conveying member 5 rotatably arranged in the direction of the arrow for conveying the magnetic toner (not shown) in 3b toward the developer accommodating portion 3a includes the developer accommodating chamber 3a and the toner accommodating chamber 3b. And a partitioning member composed of a mesh screen for regulating the amount of toner transported by the transporting member 4b toward the developer accommodating chamber 3a, and 6 is a moving magnetic field rotatably arranged in the arrow direction. A permanent magnet as a means for generating a toner, 7 is disposed so as to face the developing sleeve 1a, and a developer amount regulating member that forms a developer amount regulating region in a region facing the developing sleeve 1 and 8 is made of a magnetic material. It Also, a magnetic field movement shape adjusting member for adjusting the magnetic field shape of the moving magnetic field in the vicinity of the developer carrier 1a in the developer amount regulation region, and 9 is the conveyance of the toner conveyed by the conveyance member 4b toward the developer accommodating chamber 3a. It is a toner regulator formed of a flexible film-like member that adjusts the amount according to the amount of developer in the developer storage chamber 3a.

In this embodiment, the developer amount regulating member 7 is made of a non-magnetic member so that it can be rotatably disposed in the vicinity of the developer amount regulating member 7 and outside the developer amount regulating region. The magnetic lines of force of the permanent magnet 6 extend inward in the developer amount regulation region.

Further, in the present embodiment, the permanent magnet 6
The rotational direction and the magnetic pole configuration are such that at least the magnetic force existing in the vicinity of the surface of the developer amount regulating member 7 in the developer amount regulating region forms a magnetic force for conveying the developer container 3 inwardly. (Direction of arrow in FIG. 1) and configuration.

Further, in the present embodiment, the magnetic field shape adjusting member 8 which forms a magnetic field in cooperation with the moving magnetic field constituted by the magnetic material is arranged in the developing sleeve 1a near the developer amount regulation region. In the developer amount regulation region, a region where the variation width of the magnetic flux density near the developing sleeve 1a is small is formed.

Further, in this embodiment, the permanent magnet 6
By setting the width of the magnetic field shape adjusting member 8 to be equal to or larger than the substantial width of the magnetic poles of the magnetic field, the magnetic flux density of the magnetic field formed between the permanent magnet 6 and the magnetic field shape adjusting member 8 is reduced to the developer. In the amount regulation region, there is a magnetic field region in which the magnetic flux density increases from the developing sleeve 1a toward the developer amount regulation member 7.

The substantial width of the magnetic field is set to a width (half-width) showing a value of 50% or more of the maximum magnetic flux density of the magnetic poles of the permanent magnet measured on the developing sleeve 1a. The behavior of the magnetic field and the behavior of the magnetic toner in the developer amount regulation region, which are features of the configuration of the present invention, will be described below.

In the present invention, due to the friction between the magnetic field of the moving magnetic field generated by rotating the permanent magnet 6 in the direction of the arrow in the figure and the developer amount regulating member 7, the magnetic toner is developed in the developer amount regulating region. A conveying force that is directed inward of the container 3 is applied.

Further, among the magnetic toners carried into the developing area by the rotation of the developing sleeve 1a, the magnetic toner T which is in contact with the developing sleeve 1a is charged by frictional charging with the developing sleeve 1a. The magnetic toner T, which has been given the charged electric charge, is subjected to a force in the direction of the developing sleeve 1a due to a mirroring force, and a frictional force with the developing sleeve 1a gives a conveying force in the rotating direction of the developing sleeve 1a. To be

Therefore, in the developing device constructed as shown in FIG. 1, among the magnetic toners existing in the developer amount regulating area, the magnetic toners in contact with the developing sleeve 1a are transferred from the developing sleeve 1a. The carrying force (F1S) depending on the charged amount of the magnetic toner and the carrying force (F2S) due to the moving magnetic field of the permanent magnet 6 are given as main carrying forces.

The magnetic toner that is not in contact with the developing sleeve 1a is also subjected to the cohesive force between the magnetic toners, and is caused by the conveying force (F1) from the developing sleeve 1a and the moving magnetic field of the permanent magnet 6. The carrying force (F2) is given as the main force of the carrying force.

A magnitude relationship of F1S> F1 F2S <F2 exists between the transport forces F1S and F1 accompanying the rotation of the developing sleeve 1a and the transport forces F2 and F2S due to the moving magnetic field of the permanent magnet 6.

Therefore, if the relationship F1S> F2 ≧ F1 (1) exists, the magnetic toner conveyed to the developing area is only the sufficiently charged toner.

However, as shown in FIG.
By rotating the permanent magnet 6 in the direction of the arrow, the shape of the magnetic force line in the developer amount regulation region of the moving magnetic field formed is within the developer amount regulation region because the magnetic force line is closed only by the permanent magnet 6. Of the magnetic flux density is generated in the vicinity of the developing sleeve 1a of the permanent magnet 6 according to the density.
The carrier force F2S due to the moving magnetic field of is also changed. Further, since the location of the density of the magnetic flux density is moved by the rotation of the permanent magnet 6, the carrying force F2S due to the moving magnetic field of the permanent magnet 6 in the vicinity of the developing sleeve 1a in the developer amount regulation region is
It changes even in the same part. Therefore, the above relational expression (1)
In order to satisfy the above condition, the variation of the moving magnetic field does not substantially fluctuate with respect to the conveying force of the developing sleeve 1a in the rotation direction, for example, the moving magnetic field with respect to the rotation speed of the developing sleeve 1a. It is necessary to adopt a configuration such as increasing the moving speed of.

In the present invention, the magnetic field shape adjusting member 8 is provided in order to adjust the variation in the density of the moving magnetic field. As shown in FIG. 2B, by arranging a magnetic field shape adjusting member 8 that cooperates with the permanent magnet 6 to form a magnetic field, the shape of the moving magnetic field in the developer amount regulation region is set to that of the permanent magnet. Since the magnetic pole is always opposed to the magnetic pole, the magnetic flux density on the developing sleeve 1a is substantially constant regardless of the location. Therefore, the carrier force F2S due to the moving magnetic field of the permanent magnet 6 is almost constant regardless of the place.

Further, in this embodiment, the permanent magnet 6 is used.
The magnetic field movement range limiting member 8 with respect to the substantial width of the magnetic poles of
By setting the width of the magnetic field to be equal to or larger than that of the permanent magnet 6, the magnetic flux density of the magnetic field formed between the magnetic pole of the permanent magnet 6 and the magnetic field movement range restricting member 8 is increased from the developer carrier to the developer amount in the developer amount regulation region. There is a magnetic field region in which the magnetic flux density increases in the direction of the restricting means.

Therefore, in the developing device constructed as shown in FIG. 1, the conveying force by the permanent magnet 6 is adjusted by the magnetic flux configuration of the permanent magnet 6 and the like, so that the developing sleeve in the developer amount regulation region. For the magnetic toner in contact with 1a, there is a region in which the main force for transporting the magnetic toner in the direction of the developing sleeve 1a is a force that depends on the charge amount of the magnetic toner.

That is, the condition is such that the relational expression (1) is satisfied.

The constitution satisfying the above relational expression (1) differs depending on the characteristics of the magnetic toner, but in the present embodiment, the permanent magnets 6 have a 12-pole constitution at equal intervals, and the development in the developer amount regulation region is carried out. In the vicinity of the sleeve 1a, the material and arrangement position of the permanent magnet 6 are adjusted so that the magnetic flux density of each magnetic pole is 700 gauss or more, and further, the distance W between the developing sleeve 1a and the permanent magnet 6 is set to By adjusting the thickness of the developer amount regulating member 7 and the like, it is set within the range of about 0.2 to 2.0 mm, and the peripheral speed of rotation of the permanent magnet 6 is made substantially equal to or higher than the peripheral speed of rotation of the developing sleeve 1a. It was confirmed that the above relationship was satisfied when the structure was adopted.

The judgment as to whether the above relational expression (1) was satisfied was made as follows. When the above relational expression (1) is not satisfied, the surface cannot be brought into contact with the surface of the developing sleeve 1a at the time of applying the above-mentioned charge, and it is carried on the developing sleeve 1a and conveyed from inside the developing container 3 to outside the developing container 3. The magnetic toner which is insufficiently charged does not have the developing sleeve 1a.
Instead of being unable to obtain a triboelectric charge with, it has a charge amount due to triboelectric charging between magnetic toners. Therefore, since the charge is obtained by triboelectric charging between the magnetic toners, the charge amount distribution of the above-described magnetic toner in which charging is insufficiently applied includes charge charges of both positive and negative polarities centered on 0. The distribution is such that what is possessed is present at a ratio of approximately 50%. That is, almost 50% of the magnetic toner that is insufficiently charged
However, the toner becomes a reverse polarity toner opposite to the desired polarity.

However, when the relational expression (1) is satisfied, ideally, the opposite polarity toner does not exist. Therefore, it is possible to determine whether or not the above relational expression (1) is satisfied by measuring the distribution of the charge amount of the magnetic toner on the developing sleeve 1a and confirming the presence of the opposite polarity toner. However, depending on the magnetic toner used, there is a case where the magnetic toner originally includes a toner that is easily charged to the opposite polarity toner. Therefore, simply by checking the presence or absence of the opposite polarity toner, the above relational expression (1)
Can't judge whether is satisfied. That is, in this case, even when a sufficient triboelectric charge is applied to the magnetic toner, the reverse polarity toner exists at a certain ratio in the charge amount distribution of the magnetic toner.

Therefore, in order to determine whether or not the above relational expression (1) is satisfied by measuring the charge amount distribution of the magnetic toner and judging from the existence ratio of the opposite polarity toner, the above-mentioned originally opposite polarity is charged. It is necessary to consider the case where easy-to-use toner is included, that is, to check the ratio of magnetic toner that is originally easily charged to the opposite polarity.

Therefore, in the present invention, the charge amount distribution of the toner is measured when the carrier and the toner are sufficiently mixed and stirred and sufficient triboelectric charge is applied to the toner, and the ratio of the reverse polarity toner at that time is referred to. It is determined that the above relational expression (1) is satisfied when the ratio of the reverse polarity toner contained in the toner charge amount distribution on the developing sleeve 1a substantially coincides with the reference value.

Specifically, the measurement was carried out as follows.
As a measuring instrument, an E-SPART analyzer manufactured by Hosokawa Micron was used.

First, the distribution of the charge amount of the toner when a sufficient charge is given is measured by measuring EFV200 /
300 (manufactured by Nippon Iron Powder Co., Ltd.), toner concentration 2 wt%
Then, the charge amount distribution was measured when the mixing time was about 2 minutes, and the ratio of the amount of the opposite polarity toner at that time was used as a reference value. Next, the charge amount distribution of the toner on the developing sleeve 1a of the developing device of this embodiment was measured. When the ratio of the reverse polarity toner at this time was the same as the reference value within the measurement error range, it was determined that the above relational expression (1) was satisfied.

Further, in this embodiment, the conveying member 4
A toner regulator 9 formed of an elastic film member that adjusts the amount of toner conveyed by the conveying member 4b in the a direction according to the amount of toner in the developing container 3 is provided. The toner regulator 9 is formed of an elastic film member and is arranged so as to partition the inside of the developing container 3 between the conveying member 4a and the conveying member 4b. Therefore, when the toner amount on the conveying member 4a side is large. The toner regulator 9 does not bend due to the presence of toner, so the toner is not transported in the direction of the transport member 4a. If the amount of toner on the transport member 4a side is small, the toner regulator 9 flexes and the toner is transported. The toner is conveyed in the direction of the member 4a, and as a result, the toner amount near the developing sleeve 1a is always constant.

As described above, according to the structure of the present embodiment, in the developing device using the magnetic one-component toner, it becomes possible to convey only the toner having the stable charge amount to the developing area, and the high quality image is obtained. It has become possible to always obtain stable.

The developing device according to the present invention is not limited to the above embodiment, and the magnetic pole configuration, magnetic force, rotational speed of the permanent magnet, the shape of the magnetic field movement range limiting member 8, other developing device configurations, etc. are appropriately used. You may adjust it.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. FIG.
[FIG. 8] is a sectional view showing a second embodiment of the present invention.

In this embodiment, the magnetic field shape adjusting member 8 is replaced with a magnetic field moving range limiting member 81 in the first embodiment. That is, by narrowing the width of the magnetic field shape adjusting member 8 with respect to the width of the developer amount regulating region with respect to the rotation direction of the developing sleeve 1a, for example, the width of the developer amount regulating member 7, the developer amount regulating region is reduced. The magnetic field moving range limiting member 81 for limiting the moving magnetic field range in the vicinity of the developing sleeve 1a is used instead.

The charged amount of the magnetic toner obtained by frictional charging with the developing sleeve 1a is
It depends on the amount of work in the rotational direction (tangential direction) received from the developing sleeve 1a when passing through the developer amount regulation region, that is, the friction energy generated when sliding or rolling on the developing sleeve 1a.

Therefore, in order to increase the charge amount of the magnetic toner, at least in the developer amount regulation region, the peripheral speed on the developing sleeve 1a and the peripheral speed of the magnetic toner conveyed on the developing sleeve 1a are increased. It is necessary to have a structure that has a region where a speed difference occurs between and. Further, the magnetic toner is in contact with the developing sleeve 1a for a long time,
Further, the longer the difference in speed occurs, the larger the amount of work, and therefore the higher the amount of charge of the magnetic toner tends to be.

However, as described above, when the magnetic field shape adjusting member 8 is not provided, the shape of the magnetic force line in the developer amount regulating area of the moving magnetic field formed by rotating the permanent magnet 6 in the arrow direction is as follows. Since the magnetic lines of force are closed only by the permanent magnets 6, there are places where the magnetic flux density is dense and close in the vicinity of the developing sleeve 1a within the developer amount regulation region, and the transport force due to the moving magnetic field of the permanent magnets 6 is generated in accordance with this density. F2
S also changes. Further, since the location of the density of the magnetic flux density is moved by the rotation of the permanent magnet 6, the carrying force F2S due to the moving magnetic field of the permanent magnet 6 in the vicinity of the developing sleeve 1a in the developer amount regulation region changes even in the same portion. To do.

Further, as shown in FIG. 4, the permanent magnet 6 is
Is moved in the direction of the arrow, the moving speed of the magnetic force lines in the developer amount regulation region of the moving magnetic field is the development amount regulation because the magnetic force lines move without changing the shape due to the rotation of the permanent magnet 6. Approximately everywhere in the area.

Therefore, the speed difference depends on the difference between the carrying force F1S due to the developing sleeve 1a and the carrying force F2S due to the moving magnetic field of the permanent magnet 6, but since the carrying force F1S changes depending on the location, the magnetic force The speed difference varies depending on the toner, and the amount of charged electric charge varies.

Further, in consideration of the fluctuation of the carrying force, F2
If the respective constituent conditions are set so as to satisfy the above relational expression (1) even when S is the minimum, the speed difference becomes large when F2S is the maximum, so that the triboelectric charging of the magnetic toner takes time. In the above, the time during which the toner is in contact with the developing sleeve 1a is shortened, a sufficient charge amount due to frictional charging cannot be obtained, and F1S <F2S occurs, and the magnetic toner may not be conveyed toward the developing area. There is.

Therefore, in the present invention, in order to adjust the density variation of the moving magnetic field and adjust the time during which the magnetic toner is in contact with the developing sleeve 1a, the magnetic field moving range regulating member 81 is arranged. There is.

That is, as shown in FIG.
By arranging the magnetic field movement range limiting member 81 that cooperates with the magnetic field movement range limiting member 81, the shape of the moving magnetic field in the developer amount regulation area is such that the magnetic pole of the permanent magnet 6 is always opposed to the magnetic pole. The magnetic flux density on the sleeve 1a is almost constant regardless of the location. Magnetic field movement range limiting member 81
Is relative to the width of the developer amount regulating region with respect to the rotation direction of the developing sleeve 1a, for example, the width of the developer amount regulating member 7.
Since the width of the magnetic field moving range limiting member 81 is narrowed, the moving range of the opposing magnetic poles formed on the magnetic field moving range limiting member 81 by the permanent magnet 6 is narrower than the moving range of the magnetic pole of the permanent magnet 6. That is, the moving speed of the magnetic line of force within the developer amount limiting area is set to the developing sleeve 1a with respect to the developer amount regulating member 7.
The side is slower.

Therefore, according to the present embodiment, since the fluctuation of the moving magnetic field is eliminated, the carrying force F2S due to the moving magnetic field of the permanent magnet 6 is substantially constant regardless of the place, and the developing sleeve is also used. Since the moving speed of the magnetic force lines near 1a is slow, the time during which the magnetic toner is in contact with the developing sleeve 1a becomes long.

Further, in the present embodiment, the permanent magnet 6
By setting the width of the magnetic field movement range limiting member 8 to be equal to or larger than the substantial width of the magnetic pole of, the magnetic flux density of the magnetic field formed between the magnetic poles of the permanent magnet 6 and the magnetic field movement range limiting member 8 can be reduced. In the developer amount regulation region, there is a magnetic field region in which the magnetic flux density increases from the developing sleeve 1a toward the developer amount regulation member 7.

That is, in the developing device configuration according to the present embodiment, for example, even in a system in which it takes time to triboelectrically charge the toner, the condition that satisfies the relational expression (1) exists.

The constitution satisfying the above relational expression (1) differs depending on the characteristics of the magnetic toner, but in the present embodiment, even in the case of using the toner which takes a long time to frictionally charge the toner, the first embodiment Similar configuration conditions, that is,
The permanent magnet 6 has a structure of 12 poles at equal intervals, and in the vicinity of the developing sleeve 1a in the developer amount regulation region, the material of the permanent magnet 6 and the material of the permanent magnet 6 are set so that the magnetic flux density of each magnetic pole is 700 gauss or more. The arrangement position and the like are adjusted, and further, the distance W between the developing sleeve 1a and the permanent magnet 6 is set within the range of about 0.2 to 2.0 mm by adjusting the thickness of the developer amount regulating member 7 and the like. It has been confirmed that the above relational expression (1) is satisfied when the rotation cycle of the permanent magnet 6 is set to be substantially equal to or more than the rotation cycle of the developing sleeve 1a.

As described above, according to the structure of this embodiment, in the developing device using the magnetic one-component toner,
It is possible to convey only the toner having a stable charge amount to the developing area, and it is possible to always obtain a high quality image stably.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. FIG. 6 is a sectional view showing a third embodiment of the present invention.

In this embodiment, the arrangement position of the permanent magnet 6 arranged on the side of the regulating means in the second embodiment is set to the magnetic field movement range limiting member 81 of the second embodiment.
The developer carrying member is arranged on the downstream side of the developer carrying direction.

If the configuration of this embodiment is used, FIG.
As compared with the case shown in FIG. 7, the magnetic field lines of the magnetic field formed in cooperation between the permanent magnet 6 and the magnetic field movement range limiting member 81 are twisted as shown in FIG. 6, the magnetic flux density of the magnetic field formed between the magnetic pole of 6 and the magnetic field movement range limiting member 8 becomes denser, and the developer amount is always regulated from the developer carrier at the downstream portion of the developer amount regulation region. There is a magnetic field region in which the magnetic flux density increases in the direction of the means. Therefore, since the carrying force of the magnetic toner increases with the rotation of the permanent magnet 6,
The latitude of the constituent conditions for satisfying the relational expression (1) is widened.

In this embodiment, a line connecting the permanent magnet 6 and the center of rotation of the developing sleeve 1a is used as a base line, and the developing sleeve 1a of the magnetic field movement range limiting member 81 is set with respect to the base line.
If the arrangement position θ is between 5 ° and 45 °, where θ is the angle formed by the line connecting the downstream end of the developing sleeve 1a with the rotation center of the developing sleeve 1a, the change in the magnetic flux density can be obtained. Was confirmed to be larger than that in the case of FIG.

Therefore, in the present embodiment, even within the above-mentioned angle range, the change in magnetic flux density is 10 °, which is larger.
The magnetic field movement range limiting member 8 is provided at a predetermined position within about 40 °.
I have placed 1.

The present embodiment is not limited to the above-mentioned structure, and the same effect can be obtained by applying the developing device structure shown in the first embodiment, for example.

Further, in the present embodiment, even when the width of the magnetic field moving range limiting member 81 is equal to or less than the substantial width of the magnetic pole of the permanent magnet 6, the magnetic pole of the permanent magnet 6 and the magnetic field moving range are limited. The magnetic flux density of the magnetic field formed between the member 81 and the member 81 has a magnetic field area where the magnetic flux density increases in the downstream direction of the developer amount regulation region from the developer carrier toward the developer amount regulation means. Therefore, the latitude of the configuration conditions can be expanded.

Therefore, as described above, according to the structure of the present embodiment, in the developing device using the magnetic one-component toner, it is possible to convey only the toner having a stable charge amount to the developing area, which results in high image quality. It has become possible to always obtain stable images.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, in the configuration of the third embodiment, the magnetic field movement range limiting member 81 is developed with respect to the closest portion P between the developer amount regulating member 7 and the developing sleeve 1a in the developer amount regulating region. The sleeve 1a is arranged on the upstream side in the developer transport direction.

In the third embodiment, the degree of aggregation of the magnetic toner changes due to changes in environmental conditions and the like, and the magnetic toner carrying force due to the rotation of the permanent magnet 6 becomes relatively small. When the toner passes through the closest portion between the developer amount regulating member 7 and the developing sleeve 1a in the developer amount regulating area, the passing magnetic toner has a magnetic toner conveying force due to the rotation of the permanent magnet 6. While it is relatively small, it may not be able to return to the inside of the developing container 3 and may stay downstream of the developer amount regulation region. This is because the magnetic toner conveyance path is narrowed at the closest portion, so that the magnetic toner conveyance speed becomes slow. When a mechanical shock is applied to the developing container 3 in this state, the staying magnetic toner may be scattered to cause stains inside the machine or stains on the image.

Therefore, in this embodiment, the magnetic field movement range limiting member 81 is arranged upstream of the developing sleeve 1a in the developer conveying direction with respect to the closest portion P between the developer amount regulating member 7 and the developing sleeve 1a. With this configuration, the upstream developer transport path is wider than the most downstream developer transport path in the developer amount regulation area.

According to the present embodiment, the conveying force due to the rotation of the permanent magnet 6 is maximized on the most downstream side in the developer amount regulation area, so that the above-mentioned condition for preventing passage of the magnetic toner at the closest portion is set. The latitude of is widened.

Therefore, as described above, according to the configuration of the present embodiment, in the developing device using the magnetic one-component toner, it becomes possible to convey only the toner having a stable charge amount to the developing area, which results in high image quality. It has become possible to always obtain stable images.

The present embodiment is not limited to the above structure, and the same effect can be obtained by applying the structure shown in the first embodiment, for example.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. In the first to fourth embodiments, the case where the magnetic one-component toner is used has been described. However, the above-described embodiment is not limited to the magnetic one-component toner, and the magnetic toner or the non-magnetic toner and the magnetic toner may be used. It is also applicable when a developer having a carrier is used.

That is, the charge amount of the magnetic carrier obtained by frictional charging with the developing sleeve 1a is smaller than the charge amount of the toner, and the carrying force of the magnetic force of the permanent magnet 6 to the magnetic carrier is the toner. When the developer of which the force is larger than the conveying force by the magnetic force of the permanent magnet 6 is used, if the configuration of the above embodiment is applied, there is a configuration condition in which only the toner passes through the developer amount regulation region.

According to the constitution of the present invention, the magnetic carrier is prevented from passing through the developer amount regulating region, and an appropriate circulating state of the magnetic carrier is formed for supplying the toner toward the developer amount regulating region. It becomes possible.

The above-mentioned constitution conditions differ depending on the condition of the developer, but in the present invention, in the developer using the non-magnetic toner and the magnetic carrier, the permanent magnets 6 are arranged at equal intervals in the constitution of the developing device of the above-mentioned embodiment. 12 poles, and in the vicinity of the developing sleeve 1a within the developer amount regulation region, the material and arrangement position of the permanent magnet 6 are adjusted so that the magnetic flux density of each magnetic pole is 500 gauss or more, Further, the distance W between the developing sleeve 1a and the permanent magnet 6 is
Is adjusted to about 0.2 by adjusting the thickness of the developer amount regulating member 7 and the like.
Within the range of up to 2.5 mm, and when the rotational peripheral speed of the permanent magnet 6 is set to be substantially equal to or higher than the rotational peripheral speed of the developing sleeve 1a, the magnetic carrier can be prevented from passing through the developer amount regulation region. It was possible to form an appropriate circulation state of the magnetic carrier for supplying the toner toward the developer amount regulation region.

As described above, according to the structure of the present embodiment, in the developing device using the non-magnetic one-component toner and the magnetic carrier, it becomes possible to convey only the toner having the stable charge amount to the developing area. It is now possible to always obtain high-quality images in a stable manner.

The present embodiment is not limited to the above configuration, and the same effect can be obtained with a developer using a magnetic one-component toner and a magnetic carrier.

The magnetic toner used in the present invention includes the followings. First, as the binder resin of the toner, homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer, styrene-vinyl-toluene copolymer and the like, and those Styrene-methyl acrylate copolymer, styrene-
Ethyl acrylate copolymer, styrene-acrylic acid n-
A copolymer of styrene and an acrylic ester such as a butyl copolymer; a styrene-methyl methacrylate copolymer,
Styrene-ethyl methacrylate copolymer, styrene-
Copolymers of styrene and methacrylic acid esters such as n-butyl methacrylate copolymers; multi-component copolymers of styrene and acrylic acid esters and methacrylic acid esters; other styrene-acrylonitrile copolymers, styrene-
Styrene and other vinyl-based polymerizations of styrene-acrylonitrile-indene copolymer such as vinyl methyl ether copolymer, styrene-butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-maleic acid ester copolymer Styrene-based copolymers with polymerizable monomers; polymethylmethacrylate, polybutylmethacrylate, polyvinylacetate, polyesters, polyamides, epoxy resins, polyvinylbutyral, polyacrylic acid, phenolic resins, aliphatic or alicyclic hydrocarbon resins , Petroleum resin,
Chlorinated paraffin and the like can be used alone or in combination.

In particular, as a binder resin for a toner to be subjected to a pressure fixing method, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, higher fatty acid, polyamide resin, Polyester resins and the like can be used alone or in combination. When the polymer, copolymer, or polymer blend used contains a vinyl aromatic or acrylic monomer represented by styrene in an amount of 40 wt% or more, more desirable results are obtained.

Any appropriate pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

As a method for producing the toner having a magnetic material used in the developing device of the present invention, a conventionally known method may be used. That is, the binder resin, the charge control agent, the colorant, the magnetic substance, and the other additives are preliminarily powder-mixed by a Henschel mixer or the like, and then the mixture is kneaded for about 30 minutes by a roll mill heated to about 150 ° C. After cooling, the mixture is cooled, pulverized, and if necessary, classified to obtain a toner composition.

The following are examples of the non-magnetic toner used in the developing device according to the present invention.

First, as the binder resin for the toner, styrene and its substitution products such as polystyrene, poly-p-chlorostyrene, polyvinyltoluene, styrene-p-chlorostyrene copolymer, and styrene-vinyl-toluene copolymer are used as the binder resin. Copolymers and copolymers thereof; copolymers of styrene and acrylic ester such as styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-n-butyl acrylate copolymer; styrene A copolymer of styrene and a methacrylic acid ester such as a methyl methacrylate copolymer, a styrene-ethyl methacrylate copolymer, a styrene-n-butyl methacrylate copolymer; a styrene and an acrylic ester and a methacrylic acid ester. Multi-component copolymer; other styrene-acrylonitrile copolymer, Styrene and other vinyl-based copolymers such as ethylene-vinyl methyl ether copolymer, styrene-butadiene copolymer, styrene-vinyl methyl ketone copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid ester copolymer Styrenic copolymer with polymerizable monomer; polymethylmethacrylate, polybutylmethacrylate, polyvinylacetate, polyester, polyamide, epoxy resin, polyvinylbutyral, polyacrylic acid, phenol resin, aliphatic or alicyclic hydrocarbon Resin, petroleum resin, chlorinated paraffin, etc. can be used alone or in combination.

Any suitable pigment or dye can be used as a colorant in the toner. For example, there are known dyes and pigments such as carbon black, phthalocyanine blue, ultramarine blue, quinacridone, and benzidine yellow.

As the colorant used in the present invention, carbon black is used as a black colorant, and yellow / magenta / cyan colorants shown below are used, and those colored black are used.

As the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds,
A compound represented by an azo metal complex, a methine compound or an allylamide compound is used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 6
2, 74, 83, 93, 94, 95, 109, 110,
111, 128, 129, 147, 168 and the like are preferably used.

As the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, an anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound are used. Specifically, C.I.
I. Pigment Red 2, 3, 5, 6, 7, 23, 4
8; 2, 48; 3, 48; 4, 57; 1, 81; 1, 1
44, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221, 254 are particularly preferred.

As the cyan colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound,
A basic dye lake compound or the like can be used. In particular,
C. I. Pigment Blue 1, 7, 15, 15; 1, 1
5; 2, 15; 3, 15; 4, 60, 62, 66 and the like can be preferably used. These colorants may be used alone or in combination, and may be used in the state of solid solution. .

In the case of a color toner, the colorant of the present invention is
It is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP transparency, and dispersibility in toner. The amount of the colorant added is
It is used by adding 1 to 20 parts by weight to 100 parts by weight of the resin.

As a method for producing the non-magnetic toner used in the developing device according to the present application, a conventionally known method may be used. That is, a binder resin, a release agent composed of a low softening point substance, a colorant,
After using a pressure kneader, an extruder or a media disperser to uniformly disperse the charge control agent and the like, after colliding with the target mechanically or under a jet stream, after finely pulverizing to a desired toner particle size, Further, in addition to a method for producing a toner by a so-called pulverization method, in which a particle size distribution is sharpened through a classification process to form a toner, there is also a Japanese Patent Publication No.
Japanese Patent Publication No. 36-10231 and Japanese Patent Publication No. 59-53, in which a molten mixture is atomized in air to obtain a spherical toner by using a disk or a multi-fluid nozzle described in Japanese Patent Publication No. 45-45.
No. 856, JP-A-59-61842, and the like, a method of directly producing a toner using a suspension polymerization method, or an aqueous organic solvent in which a monomer is soluble but the obtained polymer is insoluble. It is possible to produce a toner by using a dispersion polymerization method of directly producing a toner using a solvent or an emulsion polymerization method represented by a soap-free polymerization method of directly polymerizing in the presence of a water-soluble polar polymerization initiator to produce a toner. It is possible.

If necessary, a fluidity imparting agent, a lubricant, an abrasive, a cleaning aid, a resistance adjusting agent, a charge control agent and the like may be added internally or externally to the toner.

The external additive used in the present invention preferably has a particle diameter of 1/10 or less of the weight average system of the toner particles from the viewpoint of durability when added to the toner. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope. As the external additive, for example, the following are used.

Metal oxides (aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, chromium oxide, tin oxide, zinc oxide, etc.), nitrites (silicon nitride, etc.), carbides (silicon carbide, etc.), Metal salts (calcium sulfate, barium sulfate, calcium carbonate, etc.), fatty acid metal salts (zinc stearate, calcium stearate, etc.), carbon black, silica, etc.

These external additives are used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the toner particles. These external additives may be used alone or in combination. Those subjected to a hydrophobic treatment are more preferable.

As the charge control agent used in the present invention,
Although known compounds can be used, in the case of color toner, a charge control agent which is colorless and has a high charging speed of the toner and which can stably maintain a constant charge amount is particularly preferable. Furthermore, when the direct polymerization method is used in the present invention,
A charge control agent having no polymerization inhibitory property and having no solubilized product in an aqueous system is particularly preferable.

As specific compounds, negative compounds such as salicylic acid, naphthoic acid, dicarboxylic acid metal compounds, sulfonic acids, polymer type compounds having carboxylic acid in the side chain, boron compounds, urea compounds, silicon compounds, and curly cus Arenes and the like can be used, and as the positive system, a quaternary ammonium salt, a polymer type compound having the quaternary ammonium salt in its side chain, a guanidine compound, an imidazole compound, etc. are preferably used. The charge control agent is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the resin. However, the addition of the charge control agent is not essential in the present invention, and when the two-component developing method is used, the triboelectric charging with the carrier is used, and the non-magnetic one-component elastic regulating member coating developing method is used. However, it is not always necessary to include the charge control agent in the toner by positively utilizing the triboelectric charging with the elastic regulation member and the sleeve member.

The charge amount of the toner is adjusted as follows by adjusting the addition amount of the fluidity imparting agent, the lubricant, the cleaning aid, the resistance adjusting agent, the charge control agent or the like, or the external addition amount thereof. It is preferable to adjust to an appropriate toner charge amount.

That is, as a carrier, EFV200 / 3
00 (manufactured by Nippon Iron Powder Co., Ltd.), toner concentration 2 wt%
When the mixing time is about 2 minutes, the absolute value of the charge amount of the toner obtained by the blow-off measurement method using a measuring instrument manufactured by Toshiba Chemical Co. is preferably 5 to 60 μC / g. It is preferably 5 to 50 μC / g. If it is less than 5 μC / g, the sharpness of the image will be poor and fog in the background will occur. Further, in a high temperature and high humidity environment, a decrease in image density becomes a problem. If it is larger than 60 μC / g, the electrostatic cohesive force becomes large, and it becomes difficult for the non-magnetic toner particles to aggregate, and the image quality deteriorates. In particular, in a low-temperature and low-quality environment, the mirroring power with respect to the toner carrying member becomes unnecessarily large, so that the image density is lowered and the toner is strongly adhered to the sleeve.

[0136]

As described above, the first embodiment according to the present application is described.
According to the invention described above, a developing magnetic field generating means is provided in the developer amount regulating region to reduce a change in the magnetic flux density of the moving magnetic field in the developer amount regulating region, and at least the developer carrying member regulates the developer amount. Since there is a magnetic field region in which the magnetic flux density increases in the direction of the means, it is possible to convey only the developer having a stable charge amount to the developing region, and it is possible to always obtain a high-quality image stably. became.

According to the second invention of the present application,
In the vicinity of the developer carrier in the developer amount regulation region of the first invention, a region where the moving range of the moving magnetic field is narrowed or a region where the moving magnetic field is substantially stationary is provided.
It is possible to eliminate the density variation of the moving magnetic field and increase the amount of charge of the developer.

Further, according to the third invention of the present application, the moving magnetic field generating means of the first invention or the second invention is a rotatably arranged permanent magnet having a plurality of magnetic poles. An appropriate moving magnetic field can be generated with a simple structure.

According to the fourth invention of the present application,
The moving magnetic field generating means is arranged on the side of the developer amount regulating means of any one of the first to third inventions, and cooperates with the moving magnetic field in the vicinity of the developer carrier in the developer amount regulating area. Since a magnetic member for forming a magnetic field is provided, only the developer having a stable charge amount can be transported to the developing area, and a high-quality image can always be stably obtained.

Further, according to the fifth invention of the present application, the moving magnetic field generating means arranged on the developer amount regulating means side of the fourth invention forms a magnetic field in cooperation with the moving magnetic field. Since the magnetic toner is arranged on the downstream side of the developer carrying member in the developer carrying direction, the carrying force of the magnetic toner due to the moving magnetic field increases, so that the developer having a stable charge amount is carried. Therefore, the latitude of the configuration conditions can be expanded.

According to the sixth invention of the present application,
The magnetic member that forms a magnetic field in cooperation with the moving magnetic field according to the fourth invention or the fifth invention is such that the magnetic member that is closest to the developer amount regulating means and the developer carrying member in the developer amount regulating region, Since it is arranged on the upstream side of the developer carrying member in the developer conveying direction, it is possible to widen the latitude of the constitution conditions for preventing the passage of the developer at the closest portion, and to develop only the developer having a stable charge amount. The image can be conveyed to the area and a high-quality image can always be obtained stably.

Further, according to the seventh invention of the present application, since at least one of the magnetic particles according to any one of the first to sixth inventions is a magnetic toner, development using a one-component developer is performed. In the device, a high quality image can always be obtained stably.

According to the eighth invention of the present application,
Since at least one of the magnetic particles according to any one of the first to sixth inventions is a magnetic carrier, a high-quality image can always be stably obtained in a developing device using a two-component developer.

Further, according to the ninth invention of the present application, in the developer amount regulating region according to any one of the first to eighth inventions, the developer carrier is on the developer carrier. The force for carrying and transporting the developer is a force mainly dependent on the amount of charge that is imparted to the developer by frictional charging between the developer and the developer carrier. Since the force that regulates the developer on the developer carrying member of the amount regulating means depends on the magnetic force applied to the developer, by adjusting the magnetic force, only the developer having a sufficient charge amount is charged. It can be sorted and transported.

[Brief description of drawings]

FIG. 1 is a sectional view showing a developing device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a magnetic field behavior in a developer amount regulation region of the developing device used in the first embodiment of the present invention.

FIG. 3 is a sectional view showing a developing device used in a second embodiment of the present invention.

FIG. 4 is a diagram for explaining a magnetic field behavior in a developer amount regulation region in a developing device without a magnetic field movement shape adjusting member.

FIG. 5 is a diagram for explaining a magnetic field behavior in a developer amount regulation region of a developing device used in a second embodiment of the present invention.

FIG. 6 is a sectional view showing a developing device used in a third embodiment of the present invention.

FIG. 7A is a cross-sectional view of magnetic force lines when a rotationally moving magnetic pole and a magnetic field moving range limiting member are arranged to face each other;
FIG. 6 is an explanatory diagram of magnetic lines of force when the rotationally-moving magnetic pole and the magnetic-field-moving-range limiting member are displaced from a position opposite to each other.

FIG. 8 is a sectional view showing a developing device used in a fourth embodiment of the present invention.

FIG. 9 is a diagram showing an example of an electrophotographic image forming apparatus embodying the present invention.

FIG. 10 is a cross-sectional view of a developing device using a magnetic blade fixed to a developer amount regulating member, showing an example of a conventional developing device using a magnetic one-component toner.

FIG. 11 is an explanatory diagram of magnetic flux density in a developer amount regulation region.

FIG. 12 is an explanatory diagram of toner behavior in a developer amount regulation region.

FIG. 13 is a correlation diagram between the ear length and the charged state of toner.

FIG. 14 is a cross-sectional view of an example of a conventional developing device using a non-magnetic toner, which is a developing device using a magnetic blade fixed to a developer amount regulating member.

FIG. 15 is a cross-sectional view of an example of a conventional developing device using a non-magnetic toner and a magnetic carrier, which uses a magnetic blade fixed to a developer amount regulating member.

[Explanation of symbols]

1a developing sleeve (developer carrier) 3 developing container 6 permanent magnet (moving magnetic field generating means) 7 developer amount regulating member (developer amount regulating means) 8 magnetic field moving shape adjusting member (acting magnetic field in cooperation with moving magnetic field) Magnetic member to be formed 10 Developing device 15 Photosensitive drum (electrostatic latent image carrier) 81 Magnetic field moving range limiting member (magnetic member which forms magnetic field in cooperation with moving magnetic field) T Magnetic toner (developer)

Claims (9)

[Claims] 1. A developing device for developing an electrostatic latent image on an electrostatic latent image bearing member with a developer containing at least one magnetic particle, the developer containing toner and the developer. A developing container and a developer containing the toner are carried on the surface,
Development including a developer carrying member that conveys a developer from the developing container to a developing area for developing an electrostatic latent image, and a developer amount regulating unit that regulates the coating amount of the developer on the developer carrying member. In the apparatus, a moving magnetic field generating unit that conveys the developer inward of the developing container is provided in a developer amount controlling region formed by the developer amount controlling unit and the developer carrier, A region where the change in the magnetic flux density of the moving magnetic field near the developer carrier in the regulation region is small, and a magnetic flux density is high at least in the developer amount regulation region in the direction from the developer carrier to the developer amount regulating means. The developing device is characterized in that a region is formed. 2. A region in which the moving range of the moving magnetic field is narrowed or a region in which the moving magnetic field is substantially stationary is formed near the developer carrier in the developer amount regulating region. Item 1. The developing device according to Item 1. 3. The developing device according to claim 1, wherein the moving magnetic field generating means is a rotatably arranged permanent magnet having a plurality of magnetic poles. 4. A moving magnetic field generating means is arranged on the developer amount regulating means side, and a magnetic member which forms a magnetic field in cooperation with the moving magnetic field is arranged near the developer carrier in the developer amount regulating area. The developing device according to any one of claims 1 to 3. 5. A downstream side of the developer carrying member in the developer carrying direction with respect to a magnetic member, in which a moving magnetic field generating means arranged on the developer amount regulating means side forms a magnetic field in cooperation with the moving magnetic field. The developing device according to claim 4, wherein the developing device is disposed in the developing device. 6. A magnetic member that forms a magnetic field in cooperation with a moving magnetic field develops the developer carrier with respect to the closest portion between the developer amount restricting means and the developer carrier in the developer amount restricting region. It is arranged on the upstream side in the agent transport direction.
Alternatively, the developing device according to claim 5. 7. The developing device according to claim 1, wherein at least one of the magnetic particles is a magnetic toner. 8. The developing device according to claim 1, wherein at least one of the magnetic particles is a magnetic carrier. 9. The force with which the developer carrying member carries and conveys the toner on the developer carrying member in the developer amount regulating region is determined by the frictional charge between the toner and the developer carrying member, which is the amount of charge applied to the toner. The force that mainly regulates the developer on the developer carrying member of the developer amount regulating means in the developer amount regulating region is the force that depends on the magnetic force applied to the developer. Claims 1 to 8
The developing device according to any one of 1.