JP2000275939A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To steadily replenish developer with toner by providing in a toner replenishment port with a toner replenishment port agitation member which agitates the contact part of toner with developer and toner in a toner replenishment port. SOLUTION: By providing an agitation member 10 as a toner replenishment port agitation member in a toner replenishment port 8a, the contact part (toner intake area) of developer 3b exposed on the side of the toner replenishment port 8a with toner 3a supplied to the toner replenishment port 8a is agitated. Agglomeration of the toner 3a is hindered by vibrating the vane 10b of the agitation member 10 up and down receiving the kinetic energy of the rotary motion of a toner agitator, thereby agitating the toner 3a and developer 3b in the toner intake area. This makes it possible to continuously replenish the developer with the toner steadily. Also, the use of the rotary motion of the toner agitator eliminates the need for an additional driving-means for the agitation member 10 and a required effect is achieved at a low cost.

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 a copying machine, a facsimile, a printer, and the like. More specifically, the present invention relates to a developing device comprising a toner and magnetic particles. A developer carrier for transporting the developer to an area opposed to the image carrier, a magnetic field generating means disposed inside the developer carrier, and regulating an amount of the developer carried on the developer carrier; A developer retaining member, a developer retaining portion formed by being surrounded by a surface of a cover member and a developer carrier so that the developer blocked by the developer retaining member is retained, and a developer retaining portion formed by the developer retaining member. A toner container having a toner replenishing port adjacent to the developer conveying direction upstream from the upstream and in which the contained toner is in contact with the developer carried on the developer carrier and the developer in the developer accumulating portion; And inside the toner container. The toner, it relates to a developing apparatus that captures from the toner supply port in the developer by the movement of the developer due to the developer conveyance of the developer carrying member.

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type, a magnetic particle layer is formed on a developer carrier in a container,
The toner is accommodated in the toner replenishing section in the container so as to come into contact with the magnetic particle layer, and the magnetic particles in the magnetic particle layer are moved by the rotation of the developer carrier having a magnet fixedly arranged therein, whereby the toner is moved. The toner is taken into the magnetic particle layer at the replenishing section, and the developer in which the toner and the magnetic particles are mixed is
In the developing device in which the layer is regulated by the developer regulating member and transported to the developing area, the magnet does not have a magnetic pole facing the toner replenishing unit, and is located downstream of the toner replenishing unit with respect to the rotation direction of the developer carrier. And a magnetic pole upstream of the regulating member, provided downstream of the toner replenishing section and upstream of the regulating member, at a position within a range where the magnetic field of the magnetic pole can reach, facing the developer carrier. A developing device having a cover member for forming a region filled with a magnetic particle layer (hereinafter referred to as a developer accommodating portion) between the developing device and the developer carrier (for example, Japanese Patent Application Laid-Open No.
JP-A-311537 and JP-A-9-31541 are known. In this developing device, when the developer stagnating in the developer accommodating portion has a high toner concentration and a large bulk of the developer, the developer filling rate increases and the developer hardly moves, and the developer passing through the regulating member is hardly moved. There is almost no movement except for the agent. Conversely, when the toner concentration decreases due to consumption of the toner and the volume of the developer becomes small, the filling rate of the developer in the developer accommodating portion decreases, and the developer easily moves. It is captured. Then, when the toner concentration of the developer increases and the bulk of the developer increases, the developer in the developer accommodating portion hardly moves again as described above, and the taking in of the toner stops. Further, the toner taken into the developer accommodating section is charged together with the magnetic particles by the internal pressure of the developer accommodating section and the movement of the developer in the developer accommodating section. According to this type of developing device, toner can be directly replenished to the carrier adhered to the developer carrier due to the bulk of the developer that changes in accordance with the toner concentration. The device can be simplified. Further, the number of magnetic particles can be reduced as compared with the conventional two-component developing method.
For these reasons, the size and cost of the device can be reduced.

[0003]

In the developing device having the above configuration, since there is no toner concentration sensor and the amount of magnetic particles is small, it is important how to stably supply toner to the developer on the developer carrier. It becomes. Conventionally, as a toner replenishment method, toner in a toner storage unit is agitated by a toner agitating member, and the agitated toner is moved by its own weight to a toner replenishing port to be replenished into the developer. For this reason, if the toner has a slight agglomeration or the like, the replenishing amount in that portion becomes unstable, and as a result, uniform toner replenishment is performed in a direction orthogonal to the developer conveying direction, that is, in the longitudinal direction of the developer carrying member. In some cases, image density unevenness occurs in the developed image. Further, when the degree of aggregation of the toner is large, a large amount of toner aggregation occurs in the toner supply port and the amount of toner supplied to the developer decreases, but at this time, development of an image having a large image area is continuously performed. When done,
The bulk of the developer on the developer carrier rapidly decreases, and the bulk of the developer in the developer stagnation section also sharply decreases. If the state continues further, an unexpected space is formed between the aggregated toner in the toner supply port and the developer on the downstream side in the developer transport direction, and the intake of the toner into the developer is stopped. As a result, the toner concentration decreases, and eventually, a problem such as carrier adhesion on transfer paper occurs.

[0004] The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing device capable of stably replenishing toner in a developer.

[0005]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a developing device having a magnetic field generating means therein and carrying a developer comprising toner and magnetic particles; A developer carrying member that conveys the developer to a region facing the latent image carrying member, a developer regulating member that regulates an amount of the developer carried on the developer carrying member, and a developer regulating member that is blocked by the developer regulating member. A developer stagnation portion in which the developer stagnates; a toner supply port which is a space communicating with the developer stagnation portion; and a toner container which is adjacent to the developer stagnation portion via the toner supply port and stores toner therein. A toner contacting the developer carried by the developer carrier at the toner replenishing port, the developer is moved into the developer by the movement of the developer accompanying the transport of the developer to the developer carrier. Developing device with self-control system for toner concentration There, in the toner supply port, the contact portion between the toner and the developer, and is characterized in the provision of the toner replenishing port stirring member for stirring the toner in the toner supply mouth.

According to the first aspect of the present invention, the toner supplied from the toner container to the toner supply port and the contact portion between the developer and the toner, which is the position where the toner is taken into the developer, are connected to the toner supply port. The toner is stirred by a stirring member so that the toner is not aggregated at the toner supply port.

A developing device according to a second aspect of the present invention is the developing device according to the first aspect, further comprising a toner stirring member for stirring the toner in the toner storage portion in the toner storage portion. The toner supply port stirring member is configured to stir the contact portion between the toner and the developer and the toner in the toner supply port using kinetic energy.

In the developing device of the present invention, the toner replenishing port stirring member is driven by using the kinetic energy of the toner stirring member in the toner container, and a driving device for the toner replenishing port stirring member is newly provided. Eliminate the need.

According to a third aspect of the present invention, in the developing device of the second aspect, the toner supply port agitating member is constituted by a swing member that swings around a shaft portion by kinetic energy of the toner agitating member. The shaft of the swing member is located in the toner supply port.

According to the third aspect of the present invention, the toner replenishing port stirring member is a vibrating member that vibrates about a shaft provided in the toner replenishing port. The toner in the contact portion between the toner and the developer and the toner in the toner supply port can be agitated. Thus, by simplifying the mechanism for stirring the toner, it is not necessary to change the toner supply path, the toner supply means, and the like.

According to a fourth aspect of the present invention, in the developing device of the first, second or third aspect, the toner supply port stirring member is
It is characterized by comprising a shaft portion and a plurality of convex portions provided in a comb shape on the shaft portion.

In the developing device according to the fourth aspect, the plurality of comb-shaped convex portions vibrate around the shaft portion, and the contact portion between the toner and the developer in the toner supply port and the toner in the toner supply port are removed. Stir. As a result, a gap through which the toner or the developer can pass is formed between the protrusions, and during the stirring operation, the gap is passed through the toner or the developer to allow the developer carrier to pass through the toner supply port. Avoid generating pressure in the direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which the developing device of the present invention is applied will be described below. FIG. 4 is a sectional view showing a schematic configuration of a developing device to which the present invention can be applied. The developing device is provided on a side of a photosensitive drum 1 used as a latent image carrier of a copying machine, and has a casing 2 having an opening formed toward the photosensitive drum 1, and a part thereof is exposed from the opening. A developing roller 4 carrying a developer 3 comprising toner 3a and magnetic particles (hereinafter referred to as "carrier") on its surface, and a magnet roller comprising a fixed magnet group as a magnetic field generating means fixedly disposed inside the developing roller 4 5, a doctor 6 as a developer regulating member for regulating the amount of the developer carried and conveyed on the developing roller 4, and a developer accommodating portion for the developer between the developing roller 4 and the surface of the sleeve. A
And a toner storage case 7 as a cover member, and a toner hopper 8 as a toner storage section.

The developer storage case 7 includes a developing roller 4.
A developer accommodating section A is formed in which the developer which is not supplied to the developing position opposite to the photosensitive drum 1 but is prevented from proceeding by the doctor 6 stays. Further, the toner hopper 8
Has a toner replenishing port 8a as a toner replenishing opening which is adjacent to the upstream side of the developer accommodating portion A in the developer transport direction and faces the surface of the developing roller 4, and is provided in a space adjacent to the toner replenishing port. Is provided with a toner agitator 9 for agitating and sending out the toner 3a in the hopper 8 toward the toner supply port 8a. This toner agitator 9 is
As shown by the broken line in the figure, the position of the shaft 9a and the length of the blade 9b are set so that the outermost track of the blade 9b does not touch the developer 3.

In the developing device having the above structure, the developer 3 on the developing roller 4 is conveyed with the rotation of the sleeve, and is regulated by the doctor 6 to be thinned. The thinned developer is transferred to the photosensitive drum 1 rotating in the direction of the arrow.
Is transported to the developing area opposite to. Then, in the developing area, the toner 3a is supplied to the electrostatic latent image formed on the photosensitive drum 1, and the electrostatic latent image is visualized.
The developer not used for the visualization is conveyed with the rotation of the developing roller 4 and is fed by the toner agitator 9 to take in the new toner 3a supplied from the toner supply port 8a. Return to accommodation section A. And
The internal pressure of the developer 3 containing the new toner 3a increases due to the regulation by the doctor 6, whereby the toner 3a of the developer 3
Is performed. In this manner, the toner 3a in the developer on the developing roller 4 can be charged by the internal pressure of the developer on the doctor side of the developer accommodating portion A, so that the developer such as a paddle or a screw is charged or stirred. This eliminates the need for a complicated stirring mechanism.

On the other hand, a part of the developer 3 which is not supplied to the developing area and is prevented from proceeding by the doctor 6 is moved to the vicinity of the toner supply port 8a by the internal pressure and gravity of the developer in the developer accommodating section A. Moving. The developer 3 that has moved to the toner supply port 8a is applied to the developing roller 4 by the magnetic force of the magnet.
Side and is conveyed to the doctor 6 side as the developing roller 4 rotates, thereby circulating in the developer accommodating portion A. Further, when the toner 3a supplied to the developer 3 increases and the toner concentration increases, the bulk of the developer 3 increases accordingly. Therefore, the developer 3 is transferred from the developer accommodating portion A through the toner supply port 8a. Overflow closes the toner supply port 8a. Therefore, the amount of the toner 3a taken into the developing roller 4 is reduced. As a result, the toner concentration in the developer 3 is always kept at a certain concentration or less. Conversely, when the toner concentration in the developer 3 decreases, the volume of the developer 3 in the developer accommodating section A decreases, and the toner supply port 8a is not closed. A fixed amount of toner 3a is taken in. As a result, the toner density in the developer 3 is maintained at a certain level or higher.

According to the developing device having the above structure, the toner density is self-controlled by changing the bulk of the developer in the developer accommodating section A in accordance with the state of the toner 3a taken into the developer accommodating section A. Therefore, the toner density of the developer 3 is always kept within a substantially constant density range. For this reason,
A complicated toner density control mechanism such as a toner density sensor, a P sensor, and a toner supply member is not required.

However, in the developing device having the above structure, if the image is left unused for a long time or if an image having a small image area is continuously developed, the toner 3a
Since the moving amount of the toner 3a is small, the toner 3 a
In the case of (1), aggregation may occur near the toner supply port 8a to form the bridge 11. FIG. 5 is an explanatory diagram of the developing device when the bridge 11 is formed.
As described above, when the bridge 11 is formed, the toner 3a that continuously develops an image having a large image area is used.
In a situation where consumption is large, the bulk of the developer is reduced because the toner 3a cannot be replenished to the developer accommodating portion. The toner supply port 8 is moved from the bridge 11 for the aggregated toner 3a and the developer regulating position in the developer storage case.
A gap G is formed between the developer 3b exposed on the side a,
The supply of the toner 3a stops. Such toner 3
The stop state of the supply of the “a” is more conspicuous as the toner 3a is apt to aggregate.

Therefore, the developing device according to the present embodiment is configured so that the supply of the toner 3a does not stop even when the toner 3a which easily aggregates is used. Hereinafter, an embodiment to which the developing device of the present invention is applied will be described. FIG. 1 is a sectional view of a developing device according to an embodiment of the present invention. FIG.
In the above, a stirring member 10 as a toner supply port stirring member is provided in the toner supply port 8a, and a contact portion (hereinafter, referred to as a contact portion) between the developer 3b exposed on the toner supply port 8a side and the toner 3a supplied to the toner supply port 8a. , A toner take-up area). This stirring member 10 is
Shaft portion 10a and wing portion 1 extending horizontally from shaft portion 10a
0b. When the toner agitator 9 is rotating, the tip of one wing portion 10b contacts the tip of the blade portion 9b of the toner agitator 9, and the blade portion 9b
Rises upward from below and is lifted, and the blade 9b vibrates up and down as it descends downward by gravity from where it leaves. At this time,
The remaining wing portion 10b is located in a toner take-in area of a contact portion between the developer 3b, the tip of which is exposed on the side of the toner supply port 8a, and the toner 3a supplied to the toner supply port 8a. By vibrating, the toner 3a and the developer in the vicinity of the toner intake area are stirred. That is, the wing portion 10b of the stirring member 10 is vibrated up and down by receiving the kinetic energy of the rotational movement of the toner agitator 9, and the toner 3a and the developer 3b in the toner take-in area are stirred to prevent the toner 3a from aggregating. .

According to the developing device of this embodiment, the toner 3a in the toner take-in area can be prevented from aggregating, so that the toner 3a can be stably supplied to the developer. Further, the stirring member 1 is formed by utilizing the kinetic energy of the rotational movement of the toner agitator 9.
Since 0 is vibrated, there is no need to newly provide a driving means for the stirring member 10, and the above-described effect can be obtained at low cost.

FIG. 2 is a plan view showing a modification of the stirring member 10. The position of the stirring member 10 in the rotation path and the position of the stirring member 10 in the swing path are the same as those shown in FIG. Sometimes the developing device is viewed from above. The stirring member 10 includes a shaft 10a and a shaft 1
A plurality of convex portions 10d are provided at 0a (see FIG. 3A). Further, on the shaft portion 10a,
A drive shaft 10c that is perpendicular to the shaft portion 10a and faces the toner agitator 9 is formed. When the blade portion 9b of the toner agitator 9 faces the stirring member, the tip of the drive shaft 10c is connected to the blade portion 9b. It comes into contact. On the other hand, the tip of the comb tooth 10d is located in the toner take-in area, and the interval between the comb teeth 10d is small enough to allow the toner 3a or the developer to pass but prevent the toner 3a from aggregating. ing. Specifically, the comb teeth 10d
Is desirably set to 0.5 to 30.0 mm. Further, the drive shaft 10c is brought into contact with a portion of the toner agitator 9 corresponding to the outer side of both ends (P in the figure) of the toner supply port 8a in the longitudinal direction, that is, in the vicinity of both ends of the agitator.
It is provided on the shaft portion 10a. Further, both ends of the shaft portion 10a are bent by 90 degrees toward the agitator side, and a spring 12 is attached to the end portion as shown in FIG. The mounting portion of the spring 12 is outside the toner hopper 8 further outside in the axial direction than the drive shaft 10c.

In the above configuration, when the toner agitator 9 is rotating, the drive shaft 10c contacts the tip of the blade portion 9b of the toner agitator 9, and the blade portion 9b rises upward from below and is lifted up. The portion 9b vibrates up and down by being lowered downward by the force of the spring 12 from where it is separated. On the other hand, the comb teeth 10d vibrate around the shaft portion 10a to agitate the toner 3a and the developer in the vicinity of the toner intake area. Accordingly, the comb teeth 1 of the stirring member 10 receive the kinetic energy of the toner agitator 9.
Od is caused to vibrate up and down, whereby the toner 3a and the developer 3 in the toner take-in area are stirred to prevent the toner 3a from aggregating. Since the toner 3a or the developer 3b passes between the comb teeth 10d, aggregation of the toner 3a is prevented while reducing the pressure by the stirring member 10 toward the developing roller 4. Further, since the drive shaft 10c is located outside the longitudinal direction of the toner supply port 8a, the presence of the drive shaft 10c does not hinder toner supply.

According to the above modification, the influence of the pressure on the developing roller 4 by the stirring member 10 can be reduced, and the toner can be uniformly replenished over the entire area in the longitudinal direction of the toner replenishing port 8a. Therefore, development can be performed more favorably.

[0024]

According to the developing device of the first, second, third, and fourth aspects, the aggregation of the toner in the toner supply port can be prevented. It is possible to prevent an unexpected space from being formed between the developer and the toner, so that the taking-in of the toner into the developer can be prevented from being stopped, and the toner can be stably replenished into the developer.

In particular, according to the developing device of the second aspect, it is not necessary to newly provide a driving device for the toner replenishing port agitating member. The advantage is that the cost can be reduced.

In particular, according to the developing device of the third aspect, since there is no need to change the toner supply path, the toner supply means, and the like, stable toner supply into the developer can be easily realized. Has an excellent effect.

In particular, according to the developing device of the present invention, during the stirring operation, the pressure from the toner supply port toward the developer carrier can be prevented from being generated, so that the supply pressure of the toner into the developer can be reduced. There is an excellent effect that aggregation of the toner in the toner supply port can be prevented without changing, and stable toner supply into the developer can be realized more reliably.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing a modification of the toner supply port stirring member.

FIG. 3A is a perspective view according to a modified example of a stirring member.
(B) is a front view seen from the shaft end of the stirring member. .

FIG. 4 is a cross-sectional view illustrating a schematic configuration of a developing device to which the present invention can be applied.

FIG. 5 is a sectional view of the developing device when a bridge is formed.

[Explanation of symbols]

 Reference Signs List 1 photosensitive drum 2 casing 3 developer 3a toner 4 developing roller 6 doctor 7 developer storage case 8 toner hopper 8a toner supply port 9 toner agitator 10 stirring member 10a shaft portion 10b wing portion 11 bridge 12 spring V power supply

Claims (4)

[Claims] A developer carrying member having a magnetic field generating means therein, carrying a developer comprising toner and magnetic particles, and transporting the developer to a region facing the latent image carrying member of the image forming apparatus; A developer regulating member for regulating the amount of developer carried on the developer carrying member, a developer retaining portion in which the developer blocked by the developer regulating member is retained, and a space communicating with the developer retaining portion; And a toner accommodating portion that accommodates the toner inside the toner storage portion through the toner replenishing portion through the toner replenishing portion. A developing device having a toner concentration self-control system for replenishing toner in contact with the developer to be supplied to the developer by moving the developer accompanying the transport of the developer on the developer carrier; And the contact portion with the developer, and A developing device comprising a toner supply port stirring member for stirring toner in the toner supply port. 2. The developing device according to claim 1, further comprising a toner stirring member provided in said toner storage portion for stirring toner in said toner storage portion, wherein a kinetic energy of said toner stirring member is utilized. And a toner supply port stirring member configured to stir the toner in the contact portion between the toner and the developer and the toner in the toner supply port. 3. The developing device according to claim 2, wherein the toner supply port stirring member is constituted by a swinging member which swings around a shaft portion by kinetic energy of the toner stirring member, and the shaft of the swinging member is provided. A developing unit provided in the toner supply port. 4. The developing device according to claim 1, wherein the toner supply port stirring member comprises a shaft portion and a plurality of convex portions provided in a comb-like shape on the shaft portion. Developing device.