JP3283141B2 - Developing device and image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device for an image forming apparatus such as a copying machine, a facsimile, a printer, and the like. The present invention relates to a developing device which does not require a developer supply roller for supplying a developer to a developer carrier, for example, a development roller for developing a latent image.

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type, a developer in a developer storage section is supplied to a developer carrier using a developer supply roller, and the developer adhering to the surface of the developer carrier is provided. After the excess developer is scraped off by the developer regulating member, the developer on the surface of the developer carrier is reduced to a predetermined thickness, and then the developer is applied to the latent image formed on the surface of the latent image carrier. A developing device for supplying and developing a latent image is known (for example, JP-A-6-43744 and JP-A-6-43745).
issue).

[0003]

[SUMMARY OF THE INVENTION However, in those types of the developing agent supply roller is provided in a state of contact with the developer carrying member of these devices, a developer supplying low
The developer is supplied to the developer carrier by rotating while the roller is in contact with the developer carrier. For this reason, the developer supply roller may be worn or deformed due to its rotation, and there is a problem in durability. In particular, when the developer supply roller is made of a material that is easily worn or deformed, such as an elastic body, or when the developer supply roller is rotated at a high speed, the developing
Wear and deformation of the agent supply roller were remarkable. Thus, the current
Since the toner supply roller had to be used at a rotational speed that would not cause wear and deformation of the developer , the developer supply per unit time
The amount of developer that can be supplied to the developer carrier by the supply roller is naturally limited, which has been a major obstacle to improving the developing speed of the entire developing device. In addition, even if the developer supply roller does not contact the developer carrier , the developer supply roller must be provided in the developing device, so that a space for providing the developer supply roller is required. However, the size of the apparatus is increased, and the number of parts is increased and the apparatus is complicated.

In order to solve the above-mentioned problems, the present inventor has developed a developing device which does not require a developer supply roller by making a developer regulating member function as a part of a bottom surface of a developer storage section. I came to. Although the present invention has a remarkable effect in solving the above problems, it has provided a new technical problem. That is, since the developer easily stays near the portion where the developer carrier and the developer regulating member in the developer storage device come into contact with each other, the flow of the developer due to the rotation of the developer carrier is not stabilized. As a result, there is a possibility that the amount of the developer supplied to the surface of the latent image carrier by the developer carrier cannot be kept constant. Further, there is a possibility that the developer may be clogged in the space due to the stagnation of the developer. Further, since the developer supply roller for pressing the developer against the developer carrier and frictionally charging the developer is eliminated, there is a possibility that the charge amount of the developer becomes insufficient and the image quality deteriorates.

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 which is excellent in durability, can perform high-speed development, is small, and has a simple structure. In addition, an image forming apparatus using such a developing device is required.
To provide.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a developer storing section for storing a developer, and a developer storing section for storing the developer stored in the developer storing section .
To the latent image carrier on which the latent image has been formed.
A developer carrier that contacts the surface of the developer carrier
Of developer attached to the surface of the developer carrier provided by
A developer regulating member for regulating the thickness.
Thus, the surface of the developer carrier that is moving downward is
The developer reservoir is arranged so as to face the developer reservoir.
The closer the control member is to the surface of the developer carrying member, the lower it becomes.
Constitutes a part of the bottom surface of the storage portion inclined at
The developer is regulated so that the portion contacts the surface of the developer carrier.
The member is provided, and the lower the closer to the surface of the developer carrying member, the lower the
Between the surface of the developer regulating member inclined so as to become
Place the following developer straightening member in the wedge-shaped area.
It is characterized by having. The developer rectifying member
Is opposed to and opposed to the surface of the developer carrying member.
A contact portion between the developer carrying member and the developer regulating member;
Side surface forming a passage for the developer to the developing device, and the developing carrier
Extending from the upper end of the side surface away from the surface,
As the developer carrier surface moves, the developer carrier and
The developer moving to the contact portion of the developer regulating member
An upper portion that guides away from the surface of the developer carrier
Surface and the side surface below the developer carrier.
Extending from the end, between the upper surface of the developer regulating member,
The developer, the passage of which is restricted at the contact portion, is transferred to the developer carrier
A lower surface that forms a passage for outflow away from the surface
Having.

[0007] The invention according to claim 3 is the invention according to claim 1 or 2.
A developing device, and a voltage applying means for applying a voltage to said rectifying member, is characterized in that provided <br/> and applying electric control means for controlling the voltage.

[0008] The invention of claim 4 is the invention according to claim 1 or 2.
An electrode provided near the developer carrier in the developer storage unit, a voltage application unit that applies a voltage to the electrode, and an application voltage control unit that controls the voltage. It is characterized by having.

Further, the invention according to claim 5 provides a surface of the latent image carrier.
Image formed by developing the latent image formed on the
In the image forming apparatus, as the developing device,
2,3 or features and to shall for using 4 developing devices
It is.

[0010]

According to the first to fifth aspects of the present invention , the developer in the developer storage section is formed as a part of the bottom surface of the developer storage section without using a conventionally required developer supply roller. The developer is directly supplied to the developer carrier by a regulating member, and the developer regulating member regulates the developer so that the layer thickness of the developer on the surface of the developer carrier becomes uniform.

Furthermore, since the inclined bottom portion of the developer storing portion composed of a developer regulating member is provided, it is a developer regulating member and the developer carrying member the developer in the developing time of the storage unit by its own weight It moves toward the end of the contact side.

Further , since the amount of the developer conveyed to the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other is limited by the rectifying member, the developer is developed near the position where the developer carrying member and the developer regulating member are in contact with each other. The agent does not deposit excessively. Further, since the rectifying member increases the pressure applied to the developer near the position where the developer carrier and the developer regulating member are in contact with each other, the amount of triboelectric charge of the developer can be made sufficient.

Further , the developer conveyed to the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other by the flow path formed by the flow regulating member is moved near the position where the developer carrying member and the developer regulating member are in contact with each other. The developer flows out through the flow path for allowing the developer to flow out, so that the developer is not excessively deposited near the position where the developer carrier and the developer regulating member are in contact with each other .

In particular, in the invention of claim 3 , the voltage applying means controls the voltage applied to the rectifying member by using the applied voltage controlling means, and controls the electric field generated between the developer carrier and the rectifying member. By doing so, the amount of triboelectric charge generated between the developer and the developer carrier due to the friction between the developer and the developer carrier is adjusted. Further, by controlling the electric field generated between the developer carrying member and the rectifying member to adjust the electric field acting on the developer located between the developer carrying member and the rectifying member, the flow of the developer at the position is controlled. To prevent the developer from excessively accumulating at the position where the developer carrying member and the developer regulating member are in contact with each other. Further, since the rectifying member increases the pressure applied to the developer near the position where the developer carrier and the developer regulating member are in contact with each other, the amount of triboelectric charge of the developer can be made sufficient.

[0015] In the invention of claim 4, the voltage applying means using an applied voltage control means controls the voltage applied to the electrodes of the developer carrying member near, occurs between the developer carrying member and the electrode By controlling the electric field generated and adjusting the force with which the developer is pressed against the developer carrier, the amount of triboelectric charge generated on both members due to the friction between the developer and the developer carrier is adjusted.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a developing device of an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram of a developing device 1 according to the present embodiment, and FIG. 2 is a schematic configuration diagram illustrating a main part of the developing device. 1 and 2, a photosensitive drum 3 as a latent image carrier is provided in an opening 2 of a developing device 1.
In order to develop the latent image formed on the surface, a developing roller 4 as a developer carrier that is rotatably supported opposite to the photosensitive drum 3 is provided. In the casing 5 of the developing device 1, excess developer among the developer adhered to the surface of the developing roller 4 is scraped off, and a thin layer of the developer is formed on the surface of the developing roller 4. A blade 6 is provided as a developer regulating member for frictionally charging the developed developer. The blade 6 forms a part of a developer storage unit 7, and forms a developer storage unit 7 for storing toner with the blade 6 and the casing 5.

Here, the bottom surface of the developer storage section 7 is provided with an inclination such that the end forming the contact portion N between the developing roller 4 and the blade 6 is lower than the other end. Therefore, as the developer near the developing roller 4 is used, the developer moves from the right side in FIG. Further, the developer storage section 7 is configured to have a low depth. Therefore, even if the developer is consumed, the amount of the developer located above the contact portion N between the developing roller 4 and the blade 6 does not change so much. The change in weight applied to the agent is reduced. Further, since the weight applied to the developer located at the bottom of the developer storage unit 7 by the developer located at the top thereof is reduced, the developer located at the bottom is not fixed. Further, while the developer storage unit 7 has a reduced depth,
Since the width is wide, the amount of the storable developer does not decrease.

A rectifying member 8 is disposed in a portion near the position N where the developing roller 4 and the blade 6 are in contact with each other in the developer storage section 7, that is, in a space formed by the developing roller 3 and the blade 6 and having a wedge-shaped cross section. Have been. The rectifying member 8 forms a flow path 9 for guiding the developer near a position where the developing roller 4 and the blade 6 are in contact with each other in a space formed between the rectifying member 8 and the developing roller 4. A flow path 10 for allowing the developer to flow out from the vicinity of the position where the developing roller 4 and the blade 6 are in contact with each other in the space defined by the blade 6 and itself.
To form

In the vicinity of the developing roller 4 in the developer storage section 7, the direction of rotation of the developing roller 4 of the rectifying member 8 (arrow A)
In the direction) upstream, an electrode 11 made of a plurality of metal wires arranged in parallel with the rotation axis of the developing roller is provided. A voltage is applied to the electrode 11 from an electrode bias power supply 12 as a voltage applying means, and an electric field is generated between the developing roller 4 and the electrode 11. Since the power supply bias power supply 12 can control the voltage applied to the electrode 11 by an applied voltage control unit (not shown), the electric field between the developing roller 4 and the electrode 11 can be controlled by controlling the voltage.

Further, a voltage is applied to the blade 6 by a blade bias power supply 14 and a voltage is applied to the rectifying member 8 by a rectifying member bias power supply 13 as voltage applying means. Since the voltage applied to both the blade bias power supply 14 and the rectifying member bias power supply 13 can be controlled by an applied voltage control means (not shown), by controlling the voltage, the electric field between the blade 6 and the developing roller 4 and the rectification Member 8
And the developing roller 4 can be controlled respectively.

The operation of the developing device 1 configured as described above will be described. The developer located between the developing roller 4 and the electrode 11 receives a force toward the surface of the developing roller 4 due to an electric field generated by a difference between the potential of the surface of the developing roller 4 and the potential of the electrode 11, as shown in FIG. It is pressed against the developing roller 4 rotating in the direction of arrow A. The developer is frictionally charged to negative charge by the rotation of the developing roller 4 and adheres to the surface of the developing roller 4. Here, the electric field between the developing roller 4 and the electrode 11 can be controlled by an electrode bias power supply 12 that gives a potential difference between the developing roller 4 and the electrode 11. Therefore, by adjusting the potential difference with the electrode bias power supply 12 and controlling the electric field between the developing roller 4 and the electrode 11, the force with which the developer is pressed against the developing roller 6 is adjusted, and the charge amount of the developer is adjusted. Thus, the amount of toner adhering to the surface of the developing roller 4 can be controlled. For example, if the amount of charge of the developer is insufficient and the amount of the developer adhering to the surface of the developing roller 4 tends to be insufficient, an electrode is generated to generate an electric field so that the developer receives a stronger force in the direction of the developing roller 6. The bias power supply 12 may be controlled.

As shown in FIG. 3, the developer adhering to the vicinity of the electrode 11 on the surface of the developing roller 4 by the above operation is rotated by the rotation of the developing roller 4 in the direction of arrow A so that the developing roller 4 and the blade 6 come into contact with each other. It is transported in the direction of N. In addition, not only the developer electrically attached to the surface of the developing roller 4 but also the developer located in the vicinity of the developing roller 4 rotates in the direction of the arrow A in the direction of the arrow A, so that the developing roller 4 moves in the direction of the contact portion N. Is conveyed. FIG. 3 also shows a state in which the rotating developer is transported. A part of the developer conveyed in the direction of the abutting portion N is formed by a space between the rectifying member 8 and the developing roller 4 provided in a wedge-shaped space formed by the developing roller 4 and the blade 6 in the developer storing section 7. Is conveyed to the contact portion N through the flow path 9 formed by the first member. Further, a portion of the developer that is transported in the direction of the contact portion N and that is located at a position distant from the developing roller 4 is guided by the upper wall surface of the rectifying member 8 and is transported in a direction away from the developing roller 4. You. In this manner, a part of the developer located around the developing roller 4 is transported by the rectifying member 8 in a direction away from the developing roller 4, and the contact portion N of the contact portion N between the developing roller 4 and the blade 6 is formed. Is restricted, so that the developer is prevented from staying near the contact portion N.

The developer passing through the flow path 9 is also frictionally charged by the rotation of the developing roller 4 in the direction of arrow A in this portion. Here, since the space formed between the developing roller 4 and the blade 6 is wedge-shaped, the pressure with which the developer is pressed against the developing roller 4 increases as the developer is conveyed toward the contact portion N, and the developer becomes Fully charged. A voltage is applied to the rectifying member 8 by a rectifying member bias power supply 13. The fact that the electric field between the developing roller 4 and the rectifying member 8 can be controlled by the rectifying member bias power supply 13 to control the amount of the developer adhering to the surface of the developing roller 4 is the same as the control by the electrode bias power supply 12 described above. is there. Also,

The developer adhering to the surface of the developing roller 4 by the above operation is conveyed to the contact portion N between the developing roller 4 and the blade 6 through the flow path 9 by the rotation of the developing roller 4 in the direction of arrow A. Is done. The voltage is applied to the blade 6 from the blade bias power supply 14, and the amount of the developer adhering to the developing roller 4 can be controlled by controlling the blade bias power supply 14. Control and rectifying member bias power supply 13
Is the same as the control by. At the contact portion N, the developer is pressed against the developing roller 6 by the blade 6 and is frictionally charged, and the developer adheres to the surface of the developing roller 6. An excess portion of the developer adhering to the surface of the developing roller 4 is scraped off by the blade 6, and a uniform developer layer is formed on the surface of the developing roller 6. The uniform developer layer is conveyed to the nip N2 (see FIG. 1) formed between the developing roller 6 and the photosensitive drum 6 by the rotation of the developing roller 6, and formed on the surface of the photosensitive drum 6 by an electrophotographic process. Develop the electrostatic latent image.

As described above, in the developing device 1, the electric field generated between the electrode 11 and the developing roller 4, the electric field generated between the rectifying member 8 and the developing roller 4, the electric field generated between the blade 6 and the developing roller 4, Since the developer is pressed against the developing roller 4 by the electric field generated between them, the developer is sufficiently charged and is reliably held on the surface of the developing roller 4.
Further, each electric field described above is applied to each of the bias power sources 12, 13, 1
4, the thickness of the developer layer on the surface of the developing roller 4 is adjusted by controlling each bias power supply, so that a developer layer having a desired layer thickness can be formed on the surface of the developing roller 4. Will be possible.

When the developer is excessively conveyed to the contact portion N, the developer near the contact portion N is newly conveyed to the vicinity of the contact portion N through the flow path 9. The developer is pushed out by the developer, passes through a flow path 10 formed by a space formed by the flow regulating member 8 and the blade 6, and is conveyed in a direction away from the contact portion N (upper right direction in FIG. 3). Since the flow path 10 is formed by providing the flow regulating member 8 in this manner, the developer is prevented from excessively staying near the contact portion N.

In the embodiment described above, the width of the flow path 9 formed by the developing roller 4 and the rectifying member 8 is constant, but as shown in FIG. As the width becomes narrower, that is, the distance d1 in the figure becomes the distance d
It may be configured to be shorter than 2. With this configuration, when the developer passes through the flow path due to the rotation of the developing roller 4, the developer is pressed by the developing roller 4 with a strong force. Charging is promoted.

In the embodiment described above, the electrode 11
Although a plurality of wires provided in parallel with the rotation axis of the developing roller 4 are used, a mesh wire made of a metal having a mesh size large enough to allow the developer to pass through may be used. Further, a metal plate having a curved surface as shown in FIG. When the metal plate shown in FIG. 5 is used, the developer is pressed against the surface of the developing roller 4 while being guided by the curved surface, so that the triboelectric charging of the developer is promoted .

[0029]

According to the first to fifth aspects of the present invention, without using a developer supply roller having a problem in durability,
Since the developer in the developer storage section is supplied to the developer carrier using the developer regulating member, the durability of the developing device can be improved. Further, since there is no need to use a developer supply roller , the number of components can be reduced and the developing device can have a simple structure.

Further , since the developer is conveyed by its own weight toward the end on the side where the developer regulating member and the developer carrying member are in contact with each other, it is necessary to provide a mechanism for developing and conveying in the developer storage section. And the developing device can have a simple structure.

Further , since the amount of the developer conveyed to the vicinity of the position where the developer regulating member and the developer carrying member are in contact with each other is limited by the rectifying member, the developer is excessively deposited at the position. Since this disappears, it is possible to prevent the developer at the position from being applied with excessive pressure and the developer from sticking. Further, excessive pressure is applied to the developer, so that more developer than necessary is passed between the developer regulating member and the developer carrier, and the developer is excessively supplied to the developer carrier. Can be prevented from being disturbed.

Further , since the developer near the position where the developer carrying member and the developer regulating member are in contact with each other flows out through the flow path,
Since the developer is not excessively deposited at the position,
Excessive pressure applied to the developer at the position can prevent the developer from sticking .

In particular, according to the third aspect of the present invention, the electric field between the rectifying member and the developer carrier is adjusted to control the amount of triboelectric charge generated in the developer and the developer carrier. A thin layer of the developer having a charge amount can be uniformly and stably formed on the surface of the developer carrying member. In addition, since a thin layer of the developer having a desired charge amount can be uniformly and stably formed on the surface of the developer carrier, the amount of the developer supplied to the latent image carrier is also stabilized, and the density unevenness is reduced. No image can be formed. In addition, the electric field generated between the developer carrier and the rectifying member is adjusted, the electric field acting on the developer is adjusted, and the flow of the developer between the developer carrier and the rectifying member is controlled. By preventing the developer from excessively accumulating near the position where the developer carrier and the rectifying member are in contact with each other, it is possible to prevent the developer from being fixed at the position.

Further, according to the invention of claim 4, by adjusting the electric field between the developer carrying member and the electrode, by controlling the triboelectric charge quantity generated in the developer a developer carrying member, the desired A thin layer of the developer having the above-mentioned charge amount can be uniformly and stably formed on the surface of the developer carrying member. Further, since the developer thin layer is formed stably on the surface of the developer carrier, the amount of the developer supplied to the latent image carrier is also stabilized, and an image without density unevenness can be formed.

According to the developing device of this embodiment, the depth of the developer storage portion is smaller than that of the conventional developing device. For this reason, the change in the weight of the developer located at the top of the developer with respect to the developer located at the bottom of the developer storage unit, that is, at the portion where the developer carrier and the developer regulating member come into contact with each other. Less. Therefore, the amount of the developer supplied from the developer storage unit to the developer carrier due to the change in the weight is reduced, and as a result, the thickness of the developer layer on the surface of the developer carrier is reduced. , And thus the image density. In addition, while the depth of the developer storage unit is configured to be low, the width of the developer storage unit in the direction perpendicular to the rotation axis of the developing roller 2 and perpendicular to the vertical direction (width in the horizontal direction in FIG. 1). Is configured wider than the conventional developing device, so that the amount of developer that can be stored in the developer storage section does not decrease.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram illustrating a main part of the developing device of FIG. 1;

FIG. 3 is an explanatory diagram showing a flow of a developer in the developing device of FIG. 1;

FIG. 4 is an explanatory diagram showing a schematic configuration of a developing device according to a first modified example and a flow of a developer in the developing device.

FIG. 5 is an explanatory diagram showing a schematic configuration of a developing device according to a second modified example and a flow of a developer in the developing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Opening 3 Photosensitive drum 4 Developing roller 5 Casing 6 Blade 7 Developer storage part 8 Rectifying member 9 Flow path 10 Flow path 11 Electrode 12 Electrode bias power supply 13 Rectifying member bias power supply 14 Blade bias power supply N Developing roller 4 N2 nip area

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-46013 (JP, A) JP-A-56-125776 (JP, A) JP-A-55-84959 (JP, A) JP-A-54-1984 33033 (JP, A) JP-A-5-197272 (JP, A) JP-A-5-158331 (JP, A) JP-A-6-149033 (JP, A) JP-A-54-17030 (JP, A) JP-A-60-83972 (JP, A) JP-A-63-107448 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/06-15/08

Claims (5)

(57) [Claims] 1. A developer storage unit for storing a developer, and a table for supporting the developer stored in the developer storage unit.
The surface is moved and supplied to the latent image carrier on which the latent image has been formed.
A developer carrier and the developer provided in contact with the surface of the developer carrier
Developer regulation that regulates the layer thickness of the developer attached to the surface of the carrier
A developing apparatus comprising a control member, the current which is moving downward
The developer storage section is arranged so as to face the surface of the image carrier, and the developer regulating member is closer to the surface of the developer carrier.
Construct a part of the bottom of the storage part inclined so that it becomes lower
So that the lower end thereof contacts the surface of the developer carrying member.
The developer regulating member is provided, and is inclined so as to be lower as it is closer to the surface of the developer carrier.
In the wedge-shaped region between the surface of the developer regulating member,
The following developer rectifying member is arranged.
Developing device. The developer rectifying member opposes the surface of the developer carrier and is located between the developer carrier and the surface.
The current applied to the contact portion between the developer carrier and the developer regulating member
A side surface forming a passage for the image agent, and an upper end of the side surface separated from the surface of the developing carrier.
Extend, and the development is carried out with the movement of the developer carrier surface.
To move to the contact portion between the developer carrier and the developer regulating member.
Developer in the direction away from the surface of the developer carrier.
From the lower end of the side surface so as to be separated from the developer carrier.
Extending between the upper surface of the developer regulating member and the
From the developer carrier surface
Having a lower surface forming a passage for escaping away
You. 2. The developing device according to claim 1, wherein the distance between the developing device and the surface of the developing device decreases with decreasing distance.
The above-mentioned side surface is formed so that
The developing device according to claim 1. 3. The developing device according to claim 1, further comprising voltage applying means for applying a voltage to said rectifying member, and applied voltage controlling means for controlling said voltage . 4. The developing device according to claim 1, wherein said developing device is provided near said developer carrier in said developer storage section.
And a voltage applying means for applying a voltage to the electrode, and an applied voltage controlling means for controlling the voltage . 5. A developing device for developing a latent image formed on the surface of a latent image carrier.
5. An image forming apparatus according to claim 1, wherein said image forming apparatus forms an image by developing said image forming apparatus.
An image forming apparatus using: