JPH0822188A - Developing device - Google Patents

Abstract

PURPOSE:To provide a developing device not requiring a toner supplying roller supplying a developer to a developing roller by making a blade function as a part of a developer storing part. CONSTITUTION:A developer regulating member 6 supplying the developer to the developing roller 4 and regulating the thickness of the layer of the developer on the surface of the developing roller 4 is used as a part of the bottom surface of the developer storing part 7. A flow straightening member 8 is provided in the vicinity of the contact part N of the developing roller 4 with the developer regulating member 6 and a flow passage 9 is constituted of a space formed by the flow straightening member 8 and the developing roller 4 and a flow passage 10 is constituted of a space formed by the flow straightening member 8 and the blade as well. An electrode 11 to which a bias capable of being controlled by electrode bias supply 12 is applied is provided on the upper side of the flow straightening member 8 in the developer storing part 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 of an image forming apparatus such as a copying machine, a facsimile machine or a printer, and more specifically, it supplies a developer to a latent image carrier to form it on the surface of the latent image carrier. The present invention relates to a developing device that does not require a developer supply roller that supplies a developer to a developer carrier that is, for example, a developing roller that develops a latent image.

[0002]

2. Description of the Related Art Conventionally, as a developing device of this type, a developer in a developer storage unit is supplied to a developer carrier using a developer supply roller, and among the developers adhered to the surface of the developer carrier. By scraping off the excess developer with the developer regulating member, the developer on the surface of the developer carrying member is made to have a predetermined thickness, and then this developer is applied to the latent image formed on the surface of the latent image carrying member. 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]

However, among these devices, in the type in which the developer supply roller is provided in contact with the developer carrying member, the developer replenishing roller contacts the developer carrying member. By rotating in contact with each other, the developer is replenished to the developer carrier. Therefore, the developer supply roller may be worn and deformed due to its rotation, which is a problem in terms of durability. In particular, when the developer supply roller is made of a material such as an elastic body that is easily worn or deformed, or when the developer supply roller is rotated at a high speed, the wear and the deformation of the developer supply roller are remarkable. Therefore, the developer supply roller had to be used within the rotation speed at which the developer supply roller was not worn or deformed.Therefore, the amount of developer that the developer supply roller can supply to the developer carrier per unit time is naturally limited. This is a major obstacle to improving the development speed of the entire developing device. Even if the developer supply roller does not come into contact with the developer supply member, the developer replenishing roller must be provided in the developing device. Therefore, a space for providing the developer supply roller is required. However, there is a problem that the device becomes large and the number of parts increases and the device becomes complicated.

In order to solve the above problems, the inventor of the present invention invented a developing device which does not require a developer supply roller by causing the developer regulating member to function as a part of the bottom surface of the developer storage section. I've arrived. The present invention has a remarkable effect in solving the above-mentioned problems, but on the other hand, provided a new technical problem. That is, since the developer easily stays in the vicinity of the contact between the developer carrying member and the developer regulating member in the developer storage device, the flow of the developer due to the rotation of the developer carrying member is not stable. As a result, the amount of developer supplied to the surface of the latent image carrier by the developer carrier may not be kept constant. Further, there is a possibility that the developer may be clogged in the space due to the retention of the developer. Furthermore, since the developer replenishing roller for pressing the developer against the developer carrier to frictionally charge the developer is abolished, the charge amount of the developer may be insufficient and the image quality may be deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to provide a developing device which is excellent in durability, capable of high-speed development, small in size, and simple in structure.

[0006]

In order to achieve the above-mentioned object, the invention of claim 1 is to develop the image on a developer storage portion for storing a developer and a latent image carrier having a latent image formed on the surface thereof. A developer carrying body for supplying the developer stored in the developer storing section, and a development for regulating the layer thickness of the developer adhered to the surface of the developer carrying body provided in contact with the surface of the developer carrying body And a developer regulating member, wherein the developer regulating member constitutes a part of a bottom surface of the developer storing section.

According to a second aspect of the present invention, in the developing device according to the first aspect, development is performed in the developer storage portion toward an end portion on a side where the developer regulating member and the developer carrying member are in contact with each other. It is characterized in that a slope is provided at the bottom of the developer storage unit so that the developer may move by its own weight.

According to a third aspect of the present invention, in the developing device according to the first aspect, the developer that limits the amount of the developer conveyed to the position where the developer carrying member and the developer regulating member come into contact with each other. A rectifying member is provided.

A fourth aspect of the present invention is the developing device according to the first aspect, wherein a flow path for introducing the developer to a vicinity of a position where the developer carrying member and the developer regulating member are in contact with each other, and the developing device are provided. The present invention is characterized in that a rectifying member is provided which forms a flow path for causing the developer to flow out from the vicinity of the position where the agent carrier and the developer regulating member come into contact with each other.

According to a fifth aspect of the invention, there is provided the developing device according to the fourth or fifth aspect, wherein voltage applying means for applying a voltage to the rectifying member and applied voltage control means for controlling the voltage are provided. , Are provided.

According to a sixth aspect of the present invention, in the developing device according to the first aspect, a voltage is applied to the electrode provided in the developer storage portion in the vicinity of the developer carrier and the electrode. It is characterized in that a voltage applying means and an applied voltage controlling means for controlling the voltage are provided.

[0012]

In the developing device of the present invention, the developer in the developer storage portion is regulated so as to form a part of the bottom surface of the developer storage portion without using a developer replenishing roller which has been conventionally required. A member directly supplies the developer to the developer carrier, and the developer regulating member regulates the thickness of the developer on the surface of the developer carrier to be uniform.

In the developing device of the second aspect, since the bottom of the developer storage portion is provided with an inclination, the developer in the storage portion at the time of development is brought into contact with the developer regulating member and the developer carrier by its own weight. Move toward the end of.

In the developing device of the third aspect, 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 carrying member and the developer regulating member are limited. The developer will not be excessively deposited in the vicinity of the contact position. Moreover, since the rectifying member increases the pressure applied to the developer in the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other, the triboelectric charge amount of the developer can be made sufficient.

According to another aspect of the developing device of the present invention, the developer carried 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 passage formed by the flow regulating member is regulated by the developer carrying body and the developer regulating member. Since the developer flows out from the vicinity of the position where the member is in contact with the developer through the flow path for flowing out the developer, the developer is not excessively deposited in the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other. Moreover, since the rectifying member increases the pressure applied to the developer in the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other, the triboelectric charge amount of the developer can be made sufficient.

According to another aspect of the invention, the developing device controls the voltage applied to the rectifying member by the voltage applying unit by using the applied voltage control unit, and controls the electric field generated between the developer carrier and the rectifying member. The frictional charge amount generated between the developer and the developer carrying member due to the friction between the developer and the developer carrying member 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. Is controlled to prevent excessive accumulation of the developer at the position where the developer carrying member and the developer regulating member are in contact with each other. Moreover, since the rectifying member increases the pressure applied to the developer in the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other, the triboelectric charge amount of the developer can be made sufficient.

According to a sixth aspect of the present invention, the developing device controls the voltage applied to the electrode near the developer carrying member by the voltage applying unit by using the applied voltage control unit, and the electric field generated between the developer carrying member and the electrode. Is controlled to adjust the force with which the developer is pressed against the developer carrier, thereby adjusting the triboelectric charge amount generated in both members due to the friction between the developer and the developer carrier.

[0018]

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) which is an image forming apparatus will be described below. 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 showing 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.
To develop the latent image formed on the surface, a developing roller 4 is provided as a developer bearing member that is rotatably supported so as to face the photosensitive drum 3. In the casing 5 of the developing device 1, excess developer of the developer adhering to the surface of the developing roller 4 is scraped off to form a thin layer of the developer on the surface of the developing roller 4, and at the same time, to adhere to 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 the developer storage portion 7, and the blade 6 and the casing 5 form a developer storage portion 7 for storing toner.

Here, the bottom surface of the developer storage portion 7 is inclined so that the end portion on the side forming the contact portion N between the developing roller 4 and the blade 6 is lower than the other end portion. Therefore, as the developer near the developing roller 4 is used, the developer moves from the right side in FIG. 1 toward the vicinity of the developing roller 4. The depth of the developer storage section 7 is low. 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 added by the developer located above the developer located at the bottom of the developer storage portion 7 becomes smaller, the developer located at the bottom does not stick. Further, the developer storage unit 7 has a reduced depth,
Since the width is wide, the amount of developer that can be stored does not decrease.

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

In the vicinity of the developing roller 4 in the developer storage unit 7, the direction of rotation of the developing roller 4 of the rectifying member 8 (arrow A).
In the upstream), an electrode 11 composed of a plurality of metal wires arranged parallel to 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. The power supply bias power supply 12 can control the voltage applied to the electrode 11 by an applied voltage control means (not shown). Therefore, by controlling the voltage, the electric field between the developing roller 4 and the electrode 11 can be controlled.

A voltage is applied to the blade 6 by a blade bias power source 14, and a voltage is applied to the rectifying member 8 by a rectifying member bias power source 13 as a voltage applying means. 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). Therefore, by controlling the voltage, the electric field between the blade 6 and the developing roller 4 and the rectification Member 8
The electric field between the developing roller 4 and the developing roller 4 can be controlled.

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 in the surface direction of the developing roller 4 due to the electric field generated by the difference between the potential of the surface of the developing roller 4 and the potential of the electrode 11, and is shown in FIG. It is pressed against the developing roller 4 rotating in the direction of arrow A. The developer is triboelectrically negatively charged 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 the electrode bias power supply 12 that gives a potential difference between the developing roller 4 and the electrode 11. Therefore, the potential difference is adjusted by the electrode bias power source 12, and the electric field between the developing roller 4 and the electrode 11 is controlled, whereby the force with which the developer is pressed against the developing roller 6 is adjusted, and the charge amount of the developer is adjusted. As a result, the amount of toner adhering to the surface of the developing roller 4 can be controlled. For example, when the amount of charge of the developer is insufficient and the amount of the developer attached to the surface of the developing roller 4 tends to be insufficient, the electrode is used to generate an electric field so that the developer receives a stronger force toward the developing roller 6. The bias power supply 12 may be controlled.

As shown in FIG. 3, the developer adhered to the vicinity of the electrode 11 on the surface of the developing roller 4 by the above operation is rotated by the developing roller 4 in the direction of the arrow A, and the developing roller 4 and the blade 6 are contacted with each other. It is conveyed in the direction of N. Further, 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 is rotated along with the rotation of the developing roller 4 in the direction of the arrow A, so that the developing roller 4 moves toward the contact portion N direction. Is transported. FIG. 3 also shows how the circulating developer is conveyed. A part of the developer transported in the contact portion N direction is a space formed by the developing roller 4 and the developing roller 4 in the developer storage portion 7, which is provided in a wedge-shaped space formed by the developing roller 4 and the blade 6. And is conveyed to the contact portion N through the flow path 9 formed by. Further, the portion of the developer which is conveyed in the direction of the contact portion N and which is located away from the developing roller 4 is guided by the upper wall surface of the rectifying member 8 and is conveyed in the direction of separating from the developing roller 4. It In this way, a part of the developer located around the developing roller 4 is conveyed in the direction away from the developing roller 4 by the rectifying member 8, and the abutting portion N of the abutting portion N between the developing roller 4 and the blade 6 is contacted. Since the amount of the developer conveyed to the vicinity of is limited, the developer is prevented from staying near the contact portion N.

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

The developer adhered 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. To be done. A voltage is applied to the blade 6 by the blade bias power source 14, and the amount of the developer adhering to the developing roller 4 can be controlled by controlling the blade bias power source 14 by the electrode bias power source 12 described above. Control and rectifying member bias power supply 13
It is similar to the control by. At the contact portion N, the developer is pressed against the developing roller 6 by the blade 6 and frictionally charged, and the developer adheres to the surface of the developing roller 6. An excessive portion of the developer attached 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 portion N2 (see FIG. 1) formed by the developing roller 6 and the photosensitive drum 6 by the rotation of the developing roller 6, and is 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, and the blade 6 and the developing roller 4. Since the developer is pressed against the developing roller 4 by the electric field generated during the period, the developer is sufficiently charged and is reliably held on the surface of the developing roller 4.
Further, each of the above electric fields is applied to each of the bias power sources 12, 13, 1
4, it is possible to form a developer layer having a desired layer thickness on the surface of the developing roller 4 by controlling each bias power source to adjust the developer layer thickness on the surface of the developing roller 4. It 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 after passing through the flow path 9. The developer is extruded by the developer, passes through the flow path 10 formed by the space formed by the rectifying 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 regulating member 8 is provided to form the flow path 10 in this manner, it is possible to prevent the developer from staying excessively near the contact portion N.

In the embodiment described above, the width of the flow passage 9 formed by the developing roller 4 and the rectifying member 8 is constant, but as shown in FIG. The width is narrowed, that is, the distance d1 in the figure is the distance d.
It may be configured to be shorter than 2. If this configuration is adopted, 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, so that the friction of the developer on the surface of the developing roller 4 occurs. Charge 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 is used as the above, a mesh wire made of metal having a mesh size of a size through which the developer can pass may be used instead. Alternatively, a metal plate having a curved surface as shown in FIG. 5 may be used as the electrode 11. If 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 triboelectrification of the developer is promoted. (Hereinafter, margin)

[0031]

According to the first aspect of the present invention, the developer in the developer storage portion can be used to carry the developer without using the developer replenishing roller having a problem in durability. Since it is supplied to the body, the durability of the developing device can be improved. Further, since it is not necessary to use the developer supply roller, the number of parts can be reduced and the developing device can have a simple structure.

According to the second aspect of the invention, the developer is conveyed by its own weight toward the end portion on the side where the developer regulating member and the developer carrying member are in contact with each other. It is not necessary to provide a mechanism for, and the developing device can have a simple structure.

According to the third aspect of the present invention, since the amount of the developer conveyed near the position where the developer regulating member and the developer carrying member abut with each other is limited by the rectifying member, the excessive amount of the developer is moved to that position. Since the developer does not accumulate, it is possible to prevent the developer at this position from being excessively pressed and being fixed. Further, when excessive pressure is applied to the developer, an excessive amount of developer passes between the developer regulating member and the developer carrier, and the developer is excessively supplied to the developer carrier. It is possible to prevent the image from being disturbed.

According to the invention of claim 4, the developer in the vicinity of the position where the developer carrying member and the developer regulating member are in contact with each other flows out through the flow path, so that the developer is excessively deposited at the position. Therefore, it is possible to prevent the developer from being fixed due to excessive pressure applied to the developer at that position. Further, when excessive pressure is applied to the developer, an excessive amount of developer passes between the developer regulating member and the developer carrier, and the developer is excessively supplied to the developer carrier. It is possible to prevent the image from being disturbed.

According to the invention of claim 5, the electric field between the rectifying member and the developer carrying member is adjusted to control the triboelectric charge amount generated in the developer and the developer carrying member. It is possible to uniformly and stably form a thin layer of the developer having the above on the surface of the developer carrying member. Further, since a thin layer of the developer having a desired charge amount can be uniformly and stably formed on the surface of the developer carrying member, the amount of the developer replenished to the latent image carrying member is also stable and the uneven density No image can be formed. Further, the electric field generated between the developer carrying member and the rectifying member is adjusted, the electric field acting on the developer is adjusted, and the flow of the developer between the developer carrying member and the rectifying member is controlled,
By preventing excessive accumulation of the developer 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 sticking at the position.

According to the sixth aspect of the present invention, the electric field between the developer carrier and the electrode is adjusted to control the triboelectric charge amount generated on the developer and the developer carrier, thereby achieving a desired charge. A thin layer of developer having a certain amount can be uniformly and stably formed on the surface of the developer carrier. Further, since the thin developer layer is stably formed on the surface of the developer carrying member, the amount of the developer replenished to the latent image carrying member is stable, and an image having no density unevenness can be formed.

According to the developing device of this embodiment, the depth of the developer storage portion is lower than that of the conventional developing device. For this reason, the change in weight applied by the developer located above the developer with respect to the developer located at the bottom of the developer storage portion, that is, at the contact portion between the developer carrying member and the developer regulating member. Less. Therefore, the amount of the developer supplied from the developer storage portion to the developer carrying member is less likely to change with the change in the weight, and as a result, the developer layer thickness on the surface of the developer carrying member is reduced. It is possible to suppress a change in the image density and a change in the image density. Further, while the depth of the developer storage portion is configured to be low, the width of the developer storage portion in the direction orthogonal to the rotation axis of the developing roller 2 and orthogonal to the vertical direction (width in the left-right direction in FIG. 1). Since it is configured to be wider than the conventional developing device, the amount of developer that can be stored in the developer storage unit does not decrease.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing a main part of the developing device of FIG.

FIG. 3 is an explanatory view showing a flow of a developer in the developing device of FIG.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Developing device 2 Opening part 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 Development roller 4 And blade 6 contact part N2 nip part

Claims (6)

[Claims] 1. A developer storage unit for storing a developer, a developer carrier for supplying the developer stored in the developer storage unit to a latent image carrier having a latent image formed thereon, A developing device comprising: a developer regulating member which is provided in contact with the surface of the developer bearing member and regulates the layer thickness of the developer attached to the surface of the developer bearing member. Forms a part of the bottom surface of the developer storage unit. 2. A bottom portion of the developer storage portion so that the developer moves by its own weight in the direction of the end portion of the developer storage portion where the developer control member and the developer carrying member are in contact with each other. The developing device according to claim 1, wherein an inclination is provided. 3. The developing device according to claim 1, further comprising a developer rectifying member for limiting the amount of the developer conveyed to the vicinity of a position where the developer carrying member and the developer regulating member come into contact with each other. apparatus. 4. A flow path for guiding the developer to the vicinity of a position where the developer carrying member and the developer restricting member come into contact with each other, and development from the vicinity of a position where the developer carrying member and the developer restricting member come into contact with each other. The developing device according to claim 1, further comprising a rectifying member that forms a flow path for allowing the agent to flow out. 5. The developing device according to claim 4, further comprising: a voltage applying unit that applies a voltage to the rectifying member, and an applied voltage control unit that controls the voltage. 6. An electrode provided near the developer carrying member in the developer storage unit, a voltage applying unit for applying a voltage to the electrode, and an applied voltage control unit for controlling the voltage. The developing device according to claim 1, wherein: