JP2002207355A - Developing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent toner from cohering in the opposing part between a blade 9 and a developing roller 8 by moving it in reciprocation, to stably form a uniform toner layer with sufficient electrification on the developing roller 8 for a long term, and further to prevent toner from being scattered outside a developing device, in the developing device wherein a contact part of the developing roller 8 of the blade 9 for limiting layer thickness is formed from an insulating material. SOLUTION: The above blade 9 is formed by laminating insulating layers 9b on a conductive layer 9a, and is attached to a casing 7 so that the insulating 9a comes into contact with the developing roller 8 on the edge or on the side. A blade voltage for forming an alternating electric field superposed with a DC component on the contact part between the insulating layer 9a and the developing roller 8 is applied to the above conductive layer 9a by a blade bias power source 12. This DC component is set so that the toner electrified with a prescribed polarity by a potential difference between the DC component and the above developing bias voltage is applied with the electrostatic force acting to the front side of the developing roller 8.

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. The present invention relates to a developing device which transports a latent image on a latent image carrier by transporting the latent image to a portion facing the body.

[0002]

2. Description of the Related Art A conventional developing device of this type is disclosed in
No. 4,155,043 discloses that a one-component developer is supplied to a developer carrier having a conductive surface, the developer is charged to a predetermined polarity by an electrode to which a voltage is applied, and the electrostatic latent image is developed. In this method, an AC voltage in which a DC is superimposed is applied to the electrode. According to this, the one-component developer is charged by the electrode to which the AC voltage is applied while being transported by the developer carrier, so that the charged developer has a charge amount distribution, and the gradation property is improved. It is said that an image having excellent reproducibility can be obtained. Japanese Patent Application Laid-Open No. 55-120054 discloses a developer-thickness regulating member provided at a predetermined interval on a surface of a developer-carrying member having a developer layer carried thereon, so as to alternate with a gap between both members. A device characterized by applying an external oscillating electric field is disclosed. According to this, in the gap between the developer carrying member and the developer thickness regulating member, the developer is reciprocated by the external oscillating electric field to prevent aggregation, thereby stably and uniformly on the developer carrying member for a long time. It is said that a layer of a suitable developer can be formed. Further, JP-A-59-
No. 1,748,861 discloses that a one-component developer is supplied to a non-magnetic carrier, and the developer is pressed against the developer with a regulating member disposed close to the carrier to form an electrostatic layer on the surface as a thin and uniform layer. In a developing device for sending a latent image to a holding member and applying a developer to the electrostatic latent image, the regulating member is provided with an electrode layer made of a conductive material to which an alternating voltage is applied, and an electrode layer formed on the electrode layer. An insulating layer laminated on the side of the carrier is disclosed. According to this, by applying the alternating electric field to the electrode layer, the regulating member is vibrated in synchronization with the frequency of the alternating electric field, so that the regulating member is thinly formed on the carrier even when the pressing force of the regulating member against the developer is reduced. It is said that a uniform layer of the developer can be stably formed. Further, the surface is partially exposed from the opening of the casing facing the latent image carrier, and is at least partially made of a dielectric material capable of frictionally charging the developer to a predetermined polarity. There is also known a developing device having a developer carrier that moves to return to the inside of the casing after being conveyed to a portion facing the latent image carrier.

[0003]

However, Japanese Patent Application Laid-Open No. 54-155043 mentioned above mainly mentions a method of directly charging a developer using an electrode made of a conductor. The contact portion uses a layer thickness regulating member made of an insulating material, and if necessary, the toner charging due to friction between the insulating material portion of the layer thickness regulating member and the dielectric material portion of the developer carrier and the toner. No mention is made of the use of a combination. Further, Japanese Patent Application Laid-Open No.
In Japanese Patent Application Laid-Open No. 054, a developer thickness regulating member for applying an external oscillating electric field is provided so as to be opposed to the surface of the developer carrier at a predetermined interval. ) May scatter outside the developing device through the gap between the regulating member and the surface of the developer carrying member. Further, according to the configuration disclosed in the above-mentioned JP-A-59-174861, the regulating member which is pressed against the developer on the developer carrier is vibrated in synchronization with the frequency of the alternating electric field by applying an alternating voltage. In this method, the developer collides with the insulating layer of the regulating member to cause frictional charging, and no consideration is given to electrically charging the developer directly with an alternating voltage applied to the regulating member. Therefore, the developer may not be sufficiently charged.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a developing apparatus in which at least a contact portion of a layer thickness regulating member with a developer carrying member is made of an insulating material. The developer is reciprocated at the opposed portion between the thickness regulating member and the developer carrier to prevent aggregation, so that a uniform layer of the developer having a sufficient charge amount can be stably formed on the developer carrier for a long period of time. Another object of the present invention is to provide a developing device capable of preventing the developer from scattering outside the developing device.

[0005]

In order to achieve the above object, the invention of claim 1 is directed to a layer for regulating a layer thickness of a developer carrier and a one-component developer carried on the developer carrier. In a developing device having a thickness regulating member, at least the developer carrier contact portion of the layer thickness regulating member is formed of an insulating material,
Further, a DC component that forms an electric field between the layer thickness regulating member and the developer carrying member in a direction for causing the developer charged to a predetermined polarity to flow from the layer thickness regulating member toward the developer carrying member. A voltage applying means for applying a voltage for forming an alternating electric field superimposed is provided. Claim 2
The invention relates to a developing device having a developer carrying member and a layer thickness regulating member for regulating a layer thickness of a one-component developer carried on the developer carrying member, wherein at least the developer carrying member of the layer thickness regulating member A voltage applying means for applying a voltage for forming an alternating electric field on which a direct current component is superimposed, wherein the body contact portion is made of an insulating material, and between the layer thickness regulating member and the developer carrier;
DC variable means for varying the DC component is provided. According to a third aspect of the present invention, in the developing device according to the first or second aspect, the layer thickness regulating member is brought into contact with the developer carrier with a belly pad, and the belly pad is moved in a moving direction of the developer carrier surface. The surface portions of both members are opposed to each other with a small gap on the upstream and downstream sides of the portion. According to a fourth aspect of the present invention, in the developing device according to the first or second aspect, the layer thickness regulating member is formed of a plate-shaped member, and the layer thickness regulating member is pressed against the developer carrier to be curved. It is characterized by being attached. According to a fifth aspect of the present invention, in the developing device according to the first or second aspect, the surface of the layer thickness regulating member facing the developer carrier is made of a Si-based material, a PTFE-based material,
It is characterized by being formed of a synthetic material of an i-based material and a PTFE-based material. According to a sixth aspect of the present invention, in the developing device of the first or second aspect, the surface of the layer thickness regulating member facing the developer carrier has a surface roughness of 1/3 or less of the developer particle diameter. It is characterized in that. According to a seventh aspect of the present invention, in the developing device according to the first or second aspect, the applied voltage applied to the layer thickness regulating member is set to be equal to or higher than a discharge starting voltage from the layer thickness regulating member. It is. According to an eighth aspect of the present invention, in the developing device according to the first or second aspect, the peak-to-peak voltage of the alternating electric field is set to be twice or more of a direct-current discharge starting voltage. The invention of claim 9 is
3. The developing device according to claim 1, wherein the surface of the layer thickness regulating member facing the surface of the developer carrier or at least a part of the surface of the developer carrier is conductive. The time constant in the voltage application circuit is 1 / (2
The layer thickness regulating member is configured to be sufficiently larger than πf). Where π
Is the pi, and f is the frequency of the alternating electric field. Claim 1
The invention of claim 0 is the developing device according to claim 1 or 2, wherein in the axial direction of the developer carrier, the developer carrier faces a region outside the region for carrying the developer on the developer carrier.
The layer thickness regulating member is configured to have a higher electrical resistance than a portion facing the region where the developer is carried. The invention of claim 11 is
The surface of the latent image carrying a one-component developer is partially exposed from an opening of the casing facing the latent image carrier, and is at least partially made of a dielectric material capable of frictionally charging the developer to a predetermined polarity. A developer carrying member that moves to return to the inside of the casing after being conveyed to a portion opposed to the carrying member; and a free end portion that contacts the surface of the developer carrying member that has returned to the inside of the casing. And a flow-out preventing member for preventing the developer from flowing out of the opening.
At least a contact portion of the outflow prevention member with the developer carrying member is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer. . According to a twelfth aspect of the present invention, in the developing device according to the eleventh aspect, the contact portion is made of a material that does not frictionally charge the developer or a material that can frictionally charge the developer to a polarity opposite to a predetermined charging polarity of the developer. It is characterized by having been formed. According to a thirteenth aspect of the present invention, in the developing device of the eleventh aspect, voltage applying means for applying a voltage for forming an alternating electric field is provided between the outflow prevention member and the developer carrier. It is. According to a fourteenth aspect of the present invention, in the developing device according to the thirteenth aspect, the fixed end side of the outflow prevention member is formed of an insulating material, and the free end side is formed of a conductive material. Are attached to the developer carrying member such that the portion made of the conductive material extends further inward of the casing than the contact portion with the developer carrying member, and the portion made of the conductive material Characterized in that the above-mentioned voltage is applied. Claim 15
According to a thirteenth aspect of the present invention, in the developing device according to the thirteenth aspect, the outflow prevention member is formed of a plate-like member, and the outflow prevention member is attached to the developer carrier in a state of being curved by being pressed. Things. According to a sixteenth aspect of the present invention, in the developing device of the first, second, or thirteenth aspect, as the developer carrier, a dielectric portion and a grounded conductor portion are regularly or irregularly formed on the surface with a small area. It is characterized by using an exposed one. The invention according to claim 17 is a developing device having a developer carrier and a layer thickness regulating member that regulates a layer thickness of the one-component developer carried on the developer carrier, wherein the developer carrier is provided with a latent image. The layer thickness regulating member is disposed so as to face the carrier from below, and the free end of the layer thickness regulating member that contacts the developer carrier is located at the facing portion between the developer carrier and the latent image carrier. And the layer thickness regulating member,
A voltage applying means for applying a voltage for forming an alternating electric field is provided between the layer thickness regulating member and the developer carrying member. The invention of claim 18 is the invention of claim 17
In the developing device, at least a portion of the developer carrier that is located at the facing portion is formed by laminating a medium resistance material and an insulating material, and the surface of the insulating material faces the latent image carrier. It is characterized by being arranged as described above. According to a nineteenth aspect of the present invention, in the developing device according to the eighteenth aspect, the time constant of the insulating material in the voltage applying circuit is 1 /.
The layer thickness regulating member is configured to be sufficiently larger than (2πf). Here, π is the pi, and f is the frequency of the alternating electric field.

[0006]

According to the first aspect of the present invention, the layer thickness regulating member is placed in contact with the developer carrying member, so that the developer is prevented from being scattered to the outside via the facing portion of the two members. Then, by applying a voltage that forms an alternating electric field between the two members, the developer passing through the opposing portion of the two members is vibrated,
This prevents the developer from staying in the vicinity of the facing portion. Further, as the voltage, one that forms an alternating electric field in which a DC component that forms an electric field in a direction for causing the developer charged to a predetermined polarity to move from the layer thickness regulating member side to the developer carrier side is used, This makes it possible to electrically charge the developer directly with the layer thickness regulating member.

In the second aspect of the present invention, the layer thickness regulating member is placed in contact with the developer carrying member, thereby preventing the developer from being scattered to the outside via the facing portion of the two members. Then, a voltage for forming an alternating electric field is applied between the two members to vibrate the developer passing through the opposing portion of the two members, thereby preventing the developer from staying near the opposing portion. Further, as the voltage, a voltage that forms an alternating electric field on which a DC component is superimposed is used, and the DC component is made variable, whereby the charge amount and the layer thickness of the developer can be adjusted by adjusting the DC component. To Here, the DC component may form an electric field in a direction for causing the developer charged to a predetermined polarity to travel from the layer thickness regulating member side to the developer carrier, or may be opposite to the direction. May be formed. In any case, the charge amount and the layer thickness of the developer can be adjusted according to the DC component.

According to the third aspect of the present invention, the layer thickness regulating member is brought into contact with the developer carrying member with a belly pad, and in a moving direction of the surface of the developer carrying member, an upstream side of the belly pad portion. In addition, a region where the surface portions of both members face each other with a small gap formed downstream of this portion, and the developer is vibrated by an alternating electric field in this region.

According to a fourth aspect of the present invention, the layer thickness regulating member is constituted by a plate-like member, and the layer thickness regulating member is attached to the developer carrier in a curved state by being pressed. The range in which the alternating electric field acts is limited as compared with the case where the layer thickness regulating member is attached in a linear state.

According to a fifth aspect of the present invention, the surface of the layer thickness regulating member facing the developer carrier is made of a Si-based material, PT
It is made of a FE-based material, a synthetic material of a Si-based material and a PTFE-based material, or the like, so that the developer hardly adheres to the facing surface.

According to a sixth aspect of the present invention, the surface of the layer-thickness regulating member facing the developer carrier is made to have a surface roughness of 1/3 or less of the particle diameter of the developer. The developer easily passes through the contact portion between the developer and the developer carrier.

In the invention according to claim 7, the applied voltage applied to the layer thickness regulating member is set to be equal to or higher than a discharge starting voltage from the layer thickness regulating member, thereby causing a discharge from the layer thickness regulating member. Thus, the developer can be charged even by the charge of this discharge.

According to the present invention, the peak-to-peak voltage of the alternating electric field is set to be at least twice as high as the direct-current discharge starting voltage, thereby reducing the unevenness of discharge from the layer thickness regulating member. .

According to a ninth aspect of the present invention, the surface of the layer thickness regulating member facing the surface of the developer carrier or at least a part of the surface of the developer carrier is conductive. In the developing device, the layer thickness regulating member is configured such that a time constant of the layer thickness regulating member in the voltage application circuit is sufficiently larger than 1 / (2πf). The layer thickness regulating member and the developer carrying member are prevented from leaking due to discharge from the device.

In the tenth aspect of the present invention, the layer thickness regulating member portion, which faces the region outside the developer carrying region on the developer carrying member in the axial direction of the developer carrying member, is provided. The configuration is such that the electrical resistance is higher than that of the portion facing the region where the developer is carried, so that the developer that is likely to leak is not carried as compared with the region where the developer is carried. Leakage can be reliably prevented even in the region.

In the eleventh aspect of the present invention, the outflow preventing member prevents the developer in the casing from flowing out of the casing through the opening facing the latent image carrier. Then, at least a contact portion of the outflow prevention member with the developer carrier is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the flow prevention member and the developing agent are formed. By friction of the agent carrier with the surface of the dielectric material, the surface of the dielectric material is frictionally charged to a polarity opposite to a predetermined charging polarity of the developer.

According to a twelfth aspect of the present invention, the contact portion of the outflow prevention member with the developer carrying member is made of a material that does not triboelectrically charge the developer or the developer to a polarity opposite to the predetermined charge polarity of the developer. It is made of a material that can be triboelectrically charged, and the charge amount of the charged polarity of the developer is not increased or reduced depending on the friction between the flow-down preventing member and the developer.

According to a thirteenth aspect of the present invention, an alternating electric field is formed between the outflow prevention member and the developer carrier by the voltage applying means, and the undeveloped developer on the developer carrier is removed. The alternating electric field oscillates between the flow-down preventing member and the developer carrying member to make it easy to separate from the developer carrying member, thereby facilitating replacement with a new developer.

In the fourteenth aspect of the present invention, the insulative material portion on the fixed end side of the outflow preventing member is brought into contact with the developer carrier, so that the developer in the casing flows out from the opening of the casing. To prevent Then, a voltage for forming an alternating electric field is applied to the conductive material on the free end side of the flow-down preventing member, which extends deeper in the casing than the contact portion of the flow-down preventing member with the developer carrier. Thus, the undeveloped developer on the developer carrier is vibrated by an alternating electric field at an opposing portion between the conductive material portion located on the inner side of the casing and the developer carrier. Promotes peeling off.

According to a fifteenth aspect of the present invention, the outflow prevention member is formed of a plate-like member, and the outflow prevention member is attached to the developer carrying member in a curved state by being pressed. The range of action of the alternating electric field can be regulated in accordance with

[0021] In the sixteenth aspect of the present invention,
In the developing device according to any one of 2, 7 and 13, the developer carrier may be one in which a dielectric portion and a grounded conductor portion are regularly or irregularly exposed on the surface with a small area. Friction between the dielectric portion of the carrier and a member that can come into contact with the dielectric portion, for example, a layer thickness regulating member or a flow-down preventing member, charges the dielectric portion and causes a minute closing between the dielectric portion and the conductive portion. An electric field is formed. This small closed electric field makes it possible to carry a sufficient amount of the developer on the developer carrying member. Here, in the developing device according to the first or second aspect, when the developer vibrates due to an alternating electric field between the layer thickness regulating member and the developer carrier, the developer is also affected by the minute closed electric field, and Contact between the dielectric part of the body and the developer is promoted. In particular, in the developing device of the present invention, the electric charge of the discharge from the layer thickness regulating member can be used to charge the dielectric portion. Further, in the developing device according to the thirteenth aspect, an undeveloped developer on the developer carrying member is peeled off by an alternating electric field formed at an opposing portion between the flow-down preventing member and the developer carrying member. The strong developer suction force of the closed electric field prevents the developer from sticking.

According to a seventeenth aspect of the present invention, a voltage is applied between the layer thickness regulating member for regulating the layer thickness of the one-component developer carried on the developer carrier and the developer carrier by a voltage applying means. An alternating electric field is formed by applying the voltage to vibrate the developer passing through the opposing portions of the two members, thereby forming a uniform developer layer on the developer carrier passing through the opposing portions. Then, development is performed with the developer layer facing the surface of the latent image carrier from below. Here, the free end of the layer thickness regulating member to which the voltage for forming the alternating electric field is applied is also located at the facing portion between the developer carrier and the latent image carrier, An alternating electric field is also formed between the free end and the latent image carrier. Therefore, even if unnecessary developer is scattered from the developer carrier, the developer is pulled back to the layer thickness regulating member side by the alternating electric field and further returned to the developer carrier. Since the developer carrying member is disposed so as to face the latent image carrying member from below, unnecessary gravity of the developer also contributes to the collection of the unnecessary developer to the developer carrying member. I do.

According to the eighteenth aspect, the seventeenth aspect
In the developing device, at least a portion of the developer carrier that is located at the facing portion is formed by laminating a medium resistance material and an insulating material, and the surface of the insulating material faces the latent image carrier. Thus, even when the above-mentioned voltage is applied to the medium resistance material, a discharge is hardly generated between the latent image carrier and the latent image carrier.

According to the nineteenth aspect of the present invention,
In the developing device, the layer thickness regulating member is configured such that a time constant of the insulating material in the voltage application circuit is sufficiently larger than 1 / (2πf). A sufficient withstand voltage is provided to prevent discharge from occurring with the latent image carrier.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) as an image forming apparatus will be described below. FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment. First, an outline of the entire copying machine will be described. A photosensitive drum as a latent image carrier (hereinafter, referred to as a photosensitive drum)
The photoreceptor 1 is driven to rotate clockwise by the arrow. Around the photosensitive member 1, a uniform charger 2, a latent image forming optical system (not shown), a developing device 3, a transfer charger 4, a cleaning device 5, and a static eliminator 6 are provided. In this configuration, an optical image is formed and exposed on the surface of the photoconductor 1 charged in 2 by a latent image forming optical system to form an electrostatic latent image. This electrostatic latent image is developed at 3 to form a toner image on the surface of the photoconductor 1. This toner image is transferred to the transfer paper conveyed to the surface of the photoreceptor 1 by a paper feeder (not shown) by the transfer charger 4 and discharged outside the apparatus through a fixing device (not shown). On the other hand, on the surface of the photoreceptor 1 after the transfer, the residual charge is removed by the charge remover 6 after the residual toner is removed by the cleaning device 5, and the surface is prepared for the next image formation.

Next, the developing device 3 will be described. The developing device 3 of the present embodiment includes a casing 7 having an opening facing the surface of the photoreceptor 1 and a developing roller as a developer carrier that is partially exposed from the opening and is driven to rotate counterclockwise by an arrow. 8 and the developing roller 8 at the opening exit on the surface of the developing roller 8.
A blade 9 as a layer thickness regulating member attached to the casing 7 so as to be in contact with the surface;
An agitator 10 is provided as a stirring / transporting means for transporting the material toward a contact portion between the surface and the blade 9. here,
The developing roller 8 has a structure in which at least the entire surface of the region corresponding to the developing width in the axial direction is formed of an insulating material, and at least the entire surface of the region is formed of a conductor or low-conductive material such as a metal or a conductive resin. Formed of a resistor, as will be described in detail later, at least on a surface of the region, a dielectric portion and a grounded conductor portion are regularly or irregularly exposed to the surface with a small area. , Etc. can be used. In any case, when at least a part of the surface of the developing roller 8 is used for toner triboelectric charging,
As the material of the surface portion used for the frictional charging of the toner, a material capable of charging the toner to a predetermined polarity for use in development is selected in relation to the toner on the frictional charging series. A developing bias voltage VR for forming a predetermined developing electric field in a developing region facing the photoconductor 1 is applied to the developing roller 8 by a developing bias power supply 11. The developing roller 8 may be disposed so as to face the surface of the photoconductor 1 with a predetermined gap G as shown in FIG. 1 or may be disposed so as to be in contact with the surface of the photoconductor 1. . Further, the agitator 10 can be omitted when the inner surface of the wall of the casing 7 constituting the toner accommodating portion is formed so that the toner moves to the contact portion between the developing roller 8 and the blade 9 sequentially by its own weight.

In this embodiment, for example, FIG.
As shown in (a), the blade 9 is formed by laminating an insulating layer 9b on a conductive layer 9a. This conductive layer 9a
Is made of a conductive rubber (for example, carbon dispersed urethane) plate or a metal elastic plate having a thickness of about 0.1 mm. The insulating layer 9b is made of, for example, a Si-based material, P
It is formed by applying an insulating material such as a TFE-based material or a synthetic material of a Si-based material and a PTFE-based material to a thickness of about 100 μm on the conductive layer 9a. This insulating material is used for the insulating layer 9.
When a is used for frictional charging of the toner, a material that can charge the toner to a predetermined polarity for use in development is selected in relation to the toner on the frictional charging series. Further, in order to prevent the toner from sticking to the surface of the blade 9 and to prevent the toner from staying in the vicinity of the surface, which is a cause of filming, the surface roughness of the insulating layer 9b is set to one third or less of the toner particle size. It is desirable.

In order to prevent a leak from being generated between the surface of the developing roller 8 and the surface of the developing roller 8 by applying a blade bias described later, the insulating layer 9a has a resistance R satisfying a relationship of R> 1 / (2πfC). It is desirable to form so that Here, π is a circular constant, f is an AC frequency of a blade bias described later, and C is a capacity of the insulating layer 9a. However, when the developing roller 8 in which at least a part of the surface of the developing roller 8 is a conductive or low-resistance body is used as described above, the resistance R of the blade 9 is set to R≫ in order to reliably prevent the leakage. It is desirable to form them so as to satisfy the relationship of 1 / (2πfC). In addition, since the insulating toner is not carried on both ends in the axial direction of the developing roller 8, the above-described leak is more likely to occur than in the region where the toner is carried. Therefore, particularly when both ends are formed of a conductor, or when there is a high possibility that the above-described leakage occurs due to the specific magnitude of the blade bias, the developing roller 8 faces the surface of the developing roller 8 that does not carry such toner. The blade 9 is replaced with the blade 9 facing the developing roller 8 area where the toner is carried.
It is desirable that the resistance is, for example, one digit larger than the resistance of the portion.

The blade 9 having the above-described structure is mounted on the casing 7 so that the insulating layer 9a contacts the developing roller 8.
Attach to Specifically, the blade 9 may be attached to the surface of the developing roller 8 so as to substantially contact the edge as shown in FIG. 2A, or may be attached so as to contact the stomach as shown in FIG. 2B. May be. Here, FIG.
When the edge is applied such that the free end of the blade 9 is located downstream of the fixed end of the blade 9 in the direction of movement of the developing roller surface, as shown by a circle I in FIG. Also on the upstream side in the developing roller surface movement direction, there is a region where the surfaces of both members face each other with a minute wedge-shaped gap (hereinafter referred to as an entrance wedge portion). 2B, a small wedge-shaped gap (hereinafter referred to as an outlet) is also provided downstream of the developing roller surface moving direction from the contact portion between them, as indicated by a circle E in the figure. A region where the surfaces of both members are opposed to each other at the wedge portion is generated.

A blade voltage for forming an alternating electric field in which a DC component is superimposed on a contact portion between the insulating layer 9a and the developing roller 8 is applied to the conductive layer 9a by a blade bias power supply 12. As the blade voltage, an AC having a DC component superimposed thereon can be used. The DC component is desirably set so that toner charged to a predetermined polarity by a potential difference between the DC component VBL and the developing bias voltage VR receives an electrostatic force on the surface of the developing roller 8. Further, for example, as shown in FIG. 2A, a DC component may be made variable using a variable DC power supply. Further, the blade voltage may be set to be equal to or higher than the discharge starting voltage so that the discharge charges contribute to the toner charging. For example, in the case of a blade 9 in which an insulating material is applied to a thickness of about 100 μm on a metal elastic plate having a thickness of about 0.1 mm, the DC component V _{BL is} approximately 500 volts or more, and the AC peak-to-peak The voltage V _pp satisfies the relationship of V _pp ≧ 2 × | V _BL −V _R | and the frequency of the alternating current is 500 Hz
Good results were obtained in the range of 2000 Hz.

In the above-described configuration, the toner T on the surface of the developing roller 8 which is conveyed to the contact portion between the developing roller 8 and the blade 9 by the rotation of the developing roller 8 is supplied to the entrance wedge I
Then, for example, as shown in FIG. 3 (a), it receives the electrostatic force of the alternating electric field E and penetrates into the contact portion while vibrating. Here, since the toner T vibrates, toner aggregation at the entrance wedge I can be prevented. Further, the toner repeatedly collides with the surfaces of the developing roller 8 and the blade 9 due to this vibration,
When these surfaces are used for toner triboelectric charging,
A good toner charge amount can be obtained. Further, when the blade voltage is equal to or higher than the discharge starting voltage, it is possible to improve the toner charge or the toner charge amount by the discharge charge. In particular, as shown in FIGS. 2B and 3B, when the blade 9 is placed on the belly, the toner layer having a predetermined thickness at the contact portion between the developing roller 8 and the blade 9 is removed. The toner T vibrates even at the outlet wedge portion X, and the developing roller 8
And collides with the surface of the blade 9, so that the toner chargeability can be further stabilized. Therefore, it is possible to supply a uniform toner layer made of the sufficiently charged toner T to the photoreceptor 1 and prevent the toner from sticking to the blade 9. Further, peeling off the toner T adhered to the surface of the developing roller 8 by the toner vibration due to the alternating electric field is effective in preventing toner filming on the surface of the developing roller 8.

In the above embodiment, the blade 9
Is formed by laminating the insulating layer 9b on the conductive layer 9a, but the blade 9 may be composed of only an insulator. Also in this case, by applying the same blade voltage to the blade 9 itself as in the above-described embodiment, the toner is vibrated at the entrance wedge portion and the exit wedge portion, and the blade voltage is set to be equal to or higher than the discharge starting voltage. By doing so, in addition to the frictional charging, the toner can be charged by the discharge charge. For example, a blade 9 having a resistance of 10 ¹⁴ Ω · cm or more and a thickness of about 100 μm is used, and the DC component V _{BL is} substantially −50.
When the AC peak-to-peak voltage V _pp is 0 volts or more, and the peak-to-peak voltage V _pp is twice or more the DC firing voltage and the frequency is in the range of 500 Hz to 2000 Hz, a good result is obtained. was gotten. in this case,
In order to maintain a sufficient withstand voltage between the developing roller 8 and the blade 9, at least a time constant τ (resistance R and capacitance C) between at least the electrode for applying the blade voltage and the conductive substrate of the developing roller 8.
Is set so as to satisfy the relationship of τ２1 / (2πf).

If the blade 9 is formed so that the resistance R is smaller at the downstream side in the direction of movement of the surface of the developing roller 8 than at both sides in the same direction, the charge to the toner due to vibration and discharge is applied to both parts. The assignment can also be shared.

Further, if the DC component is configured to be adjustable, when the setting of the linear velocity of the developing roller 8 is changed, the DC component is adjusted so as to be suitable for the linear velocity of the developing roller 8. It is possible to obtain an appropriate toner charge amount and layer thickness. Further, the peak-to-peak voltage and frequency of the alternating current may be adjustable.

As shown in FIGS. 2A and 2B,
When the blade 9 is attached to the developing roller 8 while being pressed and curved, the range of action of the alternating electric field can be locally limited, and the influence on the toner flow can be reduced.

Next, a developing device according to another embodiment of the present invention will be described. FIG. 4A is a schematic configuration diagram of the developing device of the present embodiment, and FIG. 4B is a partially enlarged view of the developing device. The difference between the developing device of the present embodiment and the device of the above embodiment is that the surface of the developing roller 8 is returned to the inside of the casing 7 and between the inner surface of the lower casing 7 and the surface of the developing roller 8 as an outflow preventing member. In this embodiment, a predetermined blade voltage is applied to the blade 9. The lower end of the seal blade 13 is fixed to the inner surface of the lower casing of the casing 7, and the upper end of the seal blade 13 contacts the surface of the developing roller 8.
The seal blade 13 not only prevents the toner in the casing 7 from flowing out of the opening of the casing 7 through the gap between the developing roller 8 and the inner surface of the lower casing, but also serves as a dielectric for charging the toner to a predetermined polarity. When the surface of the developing roller 8 is formed as described above, the purpose is to maintain the toner charging ability of this surface and to prevent toner filming on this surface. For this purpose, the sealing blade 13
Is a material that frictionally charges the surface of the developing roller 8 to a polarity opposite to the predetermined toner charging polarity, that is, a material that can frictionally charge the surface material of the developing roller 8 to a polarity opposite to the toner charging polarity in a friction charging series. It consists of. Further, depending on the friction with the toner, do not charge the toner, or a material that positively reduces the amount of toner charge of a predetermined toner charge polarity, that is, does not frictionally charge the toner on the friction charge series, Alternatively, it is preferable that the toner is made of a material that can be frictionally charged to a polarity opposite to a predetermined toner charging polarity. According to this, when passing through the contact portion between the developing roller 8 and the seal blade 13, the binding force of the surface of the developing roller 8 against undeveloped toner adhering to the surface of the developing roller 8 and returning to the inside of the casing 7 is reduced. Can be replaced with toner. Therefore, the toner continues to adhere to the surface of the developing roller 8, passes through the contact portion between the developing roller 8 and the blade 9 many times, and filming occurs on the surface of the developing roller 8. A decrease in holding power can be prevented.

Further, in order to prevent toner stagnation in the opposed portion between the seal blade 13 and the developing roller 8,
Similar to the blade 9, an alternating electric field may be applied to cause the toner to vibrate at the facing portion. In this case, for example, as shown in FIG. 5, the fixed end side of the seal blade 13 is formed of the above-mentioned insulating material, and the free end side thereof is formed of the conductive material. And the portion made of the conductive material contacts the developing roller 8.
May be attached to the inner side of the casing 7 so as to extend from the contact portion with the conductive material, and the seal blade bias power supply 14 may apply the voltage to a portion made of the conductive material. According to this, the amount of undeveloped toner on the developing roller 8 at the contact portion between the seal blade 13 and the developing roller 8 is reduced to reduce the amount of toner having a predetermined charging polarity, thereby reducing the binding force on the surface of the developing roller 8. Later, since the toner can be vibrated by the alternating electric field E, it is possible to effectively prevent the toner from staying at the opposed portion and prevent the filming on the surface of the developing roller 8. Therefore, maintenance of the developing electric field by the developing roller 8 and stabilization of the developer conveying force and the toner charging ability of the developing roller 8 can be achieved. In addition, it was confirmed that such an effect was sufficiently exhibited when the peak-to-peak voltage of the alternating current applied to the seal blade 13 was 1000 volts or more and the frequency was about 1000 Hz.

As shown in FIG. 4A and FIG. 5, when the seal blade 13 is made of an elastic material and is attached to the developing roller 8 in a curved state by pressing it,
The degree of curvature can adjust the opening angle of the wedge-shaped gap formed between the surfaces of both members, that is, the range of action of the alternating electric field that separates undeveloped toner from the surface of the developing roller 8. Further, the inside of the casing 7 can be sealed by pressing the free end of the seal blade 13 against the developing roller 8.

Here, the developing roller 8 suitable as the developing roller 8 in each of the above embodiments will be described. In order to deposit a desired amount of toner having a stable charge amount on the developing roller 8, the present applicant has, for example, as shown in FIG. 6A, the surface is regularly or irregularly distributed over a small area. A toner supply roller 16 is provided as a developer supply member that rotates at a position in contact with the surface of the development roller 8 using a development roller 8 including a dielectric part 15 and a conductive part that is grounded. The toner is frictionally charged at the pressure contact portion with the toner supply roller 16 and the dielectric portion 15 is frictionally charged by the toner supply roller 16 and the toner.
As shown in (b), an application is made for a developing device in which a large number of minute closed electric fields E0 are formed in the vicinity of the surface of the developing roller 8, and the triboelectrically charged toner is carried in multiple layers on the developing roller 8 by the minute closed electric field E0. (For example, Japanese Patent Application No. 2-15)
No. 110). According to the developing device of the prior invention,
It is possible to form a multi-layer toner layer having a stable charge amount on the developing roller 8. Here, the size of the dielectric portion 15 is set, for example, to a diameter of about 50 to 200 μm. It is preferable that the area ratio between the two parts is, for example, such that the area of the dielectric part 15 is in the range of 40 to 70% of the whole. The developing roller 8 shown in FIG. 6A is of a knurled type, which is formed by knurling the surface of a cored roller to form a predetermined groove, and then coating an insulating resin, for example. The core is exposed on the surface as a conductor, and the resin in the groove is exposed as a dielectric 15 on the surface. Not only the developing roller 8 formed by such knurling but also, for example,
A resin-dispersed developing roller 8 in which a conductive resin layer in which dielectric particles 41a are dispersed on a metal roller may be used.

When the developing roller 8 in which an innumerable minute closed electric field E0 for carrying toner on the surface is formed is used as the developing roller 8 in each of the above-described embodiments, various synergistic effects are exhibited. You. That is, as shown in FIG. 6A, when a developing roller 8 on which an innumerable minute closed electric field E0 is formed is used as the developing roller 8 and a predetermined blade voltage is applied to the blade 9, an entrance wedge is used. After the toner oscillates due to the alternating electric field caused by the blade voltage in the portion, the gap between the developing roller 8 and the blade 9 at the entrance wedge becomes extremely narrow, and after the toner enters the working range of the minute closed electric field E0, the dielectric on the surface of the developing roller 8 becomes large. Vibration is caused between the body portion 15 and the surface of the blade 9, and particularly the dielectric portion 1 of the toner.
5 can be promoted. Furthermore,
When the discharge is performed using a voltage equal to or higher than the discharge starting voltage as the blade voltage, not only the charge of the toner is increased by the discharge charge, but also a charge is applied to the dielectric portion 15 to strengthen the minute electric field. . Further, the toner supply roller 16 is provided by applying electric charge to the dielectric portion 15 by such discharge and applying electric charge to the dielectric portion 15 by frictional charging of the dielectric portion 15 by the blade 9. It can be omitted.

Further, if the developing roller 8 having the innumerable minute closed electric field E0 is used as the developing roller 8 and the seal blade 13 is used, the undeveloped toner is separated from the surface of the developing roller 8 by the seal blade 13. Is performed, filming on the surface of the developing roller 8 can be prevented for a long period of time.
It is possible to perform triboelectric charging or the like of the formation of micro閉電field E ₀ by stable over long. In particular, when a predetermined AC voltage is applied to the seal blade 13, the peeling ability increases, so that the filming of the developing roller 8 where filming easily occurs due to a strong toner suction force can be effectively prevented. Furthermore, even if the dielectric portion 15 is frictionally charged to a predetermined polarity by the seal blade 13,
The toner supply roller 16 can be omitted.

Next, a developing device 3 according to another embodiment will be described. FIG. 7A is a schematic configuration diagram of a copying machine employing the developing device 3 of the present embodiment, and FIG. 7B is an explanatory diagram of toner behavior in a developing area of the developing device 3. In this copying machine, the developing device 3 is disposed below the photoconductor 1.
Along with this, the uniform charger 2, the transfer charger 4, the cleaning device 5, and the like are arranged at positions different from the arrangement positions in the copying machine of FIG. Reference numeral A in FIG. 7A indicates an optical path of an exposure light beam from a latent image forming optical system (not shown), and reference numeral B indicates a transfer path of a transfer sheet. The operation of the entire copying machine is the same as that of the copying machine shown in FIG.

In the developing device 3 of this embodiment, an opening is formed in the upper part of the casing 7 facing the surface of the photoreceptor 1 so as to partially expose the developing roller 8, and is rotated so as to be partially exposed from the opening. A driven developing roller 8 is provided. A predetermined developing bias is applied to the developing roller 8 from a power source (not shown). A blade 9 as a layer thickness regulating member is attached to the casing 7 such that a free end thereof comes into contact with the surface of the developing roller 9 exposed from the opening of the casing 7. Since the base end of the blade 9 is fixed to the casing 7 and the free end thereof is in contact with the surface of the developing roller 9, the blade 9 also functions as a sealing member between the surface of the developing roller 9 and the opening edge of the casing 7. Due to the rotation of the developing roller 8, the free end portion comes into contact with the surface of the developing roller 8 that has passed through the contact portion of the blade 9 and directly opposed to the surface of the photosensitive member 1 without contact, for example, and then returned to the casing 7. As described above, the seal blade 13 as the outflow prevention member is attached to the casing 7. Further, a one-component developer composed of a non-magnetic toner is contained in the casing 7, and an agitator 10 for supplying the contained toner to the surface of the developing roller 8 is provided. Instead of the agitator 10, a sponge roller or the like that supplies toner while rubbing the surface of the developing roller 8 may be used.

In this embodiment, as shown in FIG. 7B, a voltage for forming an alternating electric field between the developing roller 9 and the photosensitive member 1 by the blade bias power supply 12 is applied to the blade 9 as shown in FIG. Is applied. As the applied voltage, for example, the same voltage as the voltage of the blade bias power supply 12 in the above embodiment can be used. In the illustrated example, the blade 9 is formed by laminating an insulating layer 9b on the surface of the blade body 9a made of a medium resistance material on the photoconductor 1 side. When the medium resistance material frictionally charges the toner to a predetermined polarity by toner friction between the medium resistance material and the developing roller 9, the relationship between the medium resistance material and the toner on the friction charging series is a predetermined polarity for use in development. A material that can charge the toner is selected. Further, in order to prevent the toner from sticking to the surface of the blade 9 and to prevent the toner from staying in the vicinity of the surface, which is a cause of filming, the surface roughness of the insulating layer 9b is set to one third or less of the toner particle size. It is desirable. Further, the insulating layer 9b has a time constant τ (the product of the resistance R and the capacitance C) satisfying the relationship of τ≫1 / (2πf) in order to reliably prevent discharge between the photoconductor 1 and the insulating layer 9b. It is desirable to set as follows.

In the illustrated example, the blade 9 is attached to the developing roller 9 such that the free edge of the blade 9 is located substantially vertically below the rotation center of the photosensitive member 1. Further, as shown in FIG. 7 (b), the blade 9 is in contact with the developing roller 9 and has a small wedge-shaped upstream and downstream in the developing roller surface moving direction from the contact portion with the developing roller 9. A region where the surfaces of both members face each other with a gap of.

In the above configuration, the toner on the surface of the developing roller 8 which is conveyed to the contact portion between the developing roller 8 and the blade 9 by the rotation of the developing roller 8 is supplied to the entrance wedge by the entrance wedge.
For example, as shown in FIG. 7B, it receives the electrostatic force of the alternating electric field E and penetrates into the contact portion while vibrating. here,
Since the toner vibrates, aggregation of the toner at the entrance wedge portion can be prevented. Further, the toner is caused to vibrate by the vibration,
When the surface is used for frictional charging of toner, a good amount of toner charge can be obtained. In particular, as shown,
When the blade 9 is resting on the stomach, the developing roller 8
The toner of the toner layer having a predetermined thickness at the contact portion between the toner and the blade 9 vibrates even at the outlet wedge portion and collides with the surface of the developing roller 8 and the blade 9 many times, so that the toner charging property is further stabilized. Can be. Therefore, it is possible to supply a uniform toner layer made of the sufficiently charged toner T to the photoreceptor 1 and prevent the toner from sticking to the blade 9. Then, in the developing area where the surface of the developing roller 8 directly faces the photoconductor 1, the toner on the developing roller 8 is transferred to the image portion of the latent image on the photoconductor 1. In this development area, unnecessary toner that does not adhere to the image portion floats away from the development roller 8 due to an alternating electric field formed between the blade 9 and the development roller 8 or due to the development electric field. May be scattered. However, in this embodiment, since the tip of the blade 9 to which the predetermined voltage is applied is located at the opposing portion between the photosensitive member 1 and the developing roller 8, the distance between the photosensitive member 1 and the tip of the blade 9 is large. Blade 9 by the alternating electric field of
Side, and is further returned to the surface of the developing roller 9. In particular, since the developing roller 8 is opposed to the photoreceptor 1 from below, the toner is returned to the surface of the developing roller 8 by its own weight.
Of course, an electric field for moving the toner toward the developing roller 8 is formed between the background portion of the latent image and the developing roller 9.

As described above, in this embodiment, toner scattering from the surface of the developing roller 8 can be effectively prevented. In addition,
While the photosensitive member 1 was driven at a linear speed of 120 mm / sec, a negative latent image was written in a region where uniform charging was performed at −800 V, and reversal development was performed while applying a developing bias of −600 V to the developing roller 8. At this time, blade 9
And the time constant is about 1.7 × 10 ⁴ seconds (the insulating layer 9b
Has a resistance value of 10 ¹⁷ Ωcm, a thickness of 0.1 mm, and a capacitance of 0.1
8 .mu.F), and an alternating voltage having a frequency of 0.5 to 1.5 KHz and a peak-to-peak voltage of 1.5 KV with -600 V superimposed thereon was applied thereto. According to this,
Sufficient pressure resistance of the blade was obtained. The insulating layer 9
As the material b, Si sheet, nylon 6 (trademark),
Nylon 66 ™ was preferred.

[0048]

According to the first aspect of the present invention, since the layer thickness regulating member is in contact with the developer carrying member, it is possible to prevent the developer from being scattered to the outside via the opposed portions of the two members. Also,
An alternating electric field is formed between the two members to vibrate the developer passing through the opposing portion, thereby preventing the developer from staying near the opposing portion and preventing the developer from sticking to the layer thickness regulating member. In addition, it is possible to improve the frictional charging effect when the surface of the developer carrier and the surface of the layer thickness regulating member are used for frictional charging of the developer. Furthermore, since the voltage is used to form an alternating electric field in which a DC component for forming an electric field in a direction for causing the developer charged to a constant polarity to move from the layer thickness regulating member side to the developer carrier is used. Further, the developer can be directly electrically charged by the layer thickness regulating member.

According to the second aspect of the present invention, since the layer thickness regulating member is in contact with the developer carrying member, it is possible to prevent the developer from being scattered to the outside via the facing portion of both members. Further, since a voltage for forming an alternating electric field is applied between the two members to vibrate the developer passing through the opposing portion of the two members, the developer is prevented from staying near the opposing portion, and the layer thickness is reduced. It is possible to prevent the developer from sticking to the regulating member, and it is possible to improve the triboelectric charging effect when the surface of the developer carrier or the surface of the layer thickness regulating member is used for triboelectric charging of the developer. Further, as the voltage, one that forms an alternating electric field on which a DC component is superimposed is used, and since the DC component is made variable, the charge amount of the developer and the developer can be adjusted by adjusting the DC component. .

According to the third aspect of the present invention, the layer thickness regulating member is brought into contact with the developer carrying member with a belly pad, and the upstream of the belly pad portion in the moving direction of the developer carrying member surface. Not only on the side, but also on the downstream side from this part, form a region where the surface parts of both members face each other with a small gap,
Since the developer is vibrated by the alternating electric field in this region, the effect of preventing the developer from being fixed can be further enhanced.

According to the fourth aspect of the present invention, the layer thickness regulating member is formed of a plate-like member, and the layer thickness regulating member is attached to the developer carrying member in a curved state by pressing the member. Compared to the case where the layer thickness regulating member is attached in a linear state, the range in which the alternating electric field acts is limited,
It is possible to prevent the developer from being scattered due to the action range of the alternating electric field being too wide.

According to the fifth aspect of the present invention, the surface of the layer thickness regulating member facing the developer carrier is made of a Si-based material, PTF.
It is made of an E-based material, a synthetic material of a Si-based material and a PTFE-based material, and the like, so that the developer does not easily adhere to the opposing surface. The action of the alternating electric field between the regulating member and the developer carrier can be favorably maintained.

According to the sixth aspect of the present invention, the roughness of the surface of the layer thickness regulating member facing the developer carrying member is set to a value of 1% of the developer particle size.
Since the surface roughness is set to not more than / 3, the developer can easily pass through the contact portion between the layer thickness regulating member and the developer carrier, so that the developer can be prevented from sticking to the layer thickness regulating member. Further, even in a developing device in which the developer is charged at the contact portion by frictional charging with the layer thickness regulating member or the surface of the developer carrier, the developer charged at the contact portion does not slip, and the surface of the developer carrier is not slipped. It can be discharged from the contact portion by the movement.

According to the seventh aspect of the present invention, since the applied voltage applied to the layer thickness regulating member is set to be equal to or higher than the discharge starting voltage from the layer thickness regulating member, a discharge is generated from the layer thickness regulating member. Also, the developer can be charged by the charge of this discharge. Further, even in a developing device in which the developer is charged by frictional charging due to the layer thickness regulating member or the surface of the developer carrying member, the frictional charging can be stopped by the charging by the discharge charge to stabilize the charging of the developer.

According to the eighth aspect of the present invention, the peak-to-peak voltage of the alternating electric field is set to a value equal to two times the DC starting voltage.
Since the value is set to twice or more, unevenness of discharge from the layer thickness regulating member can be reduced, and a sufficient developer charge amount can be obtained.

According to the ninth aspect of the present invention, the surface of the layer thickness regulating member facing the surface of the developer carrier or at least a part of the surface of the developer carrier is conductive.
Alternatively, in the developing device, the layer thickness regulating member is configured such that a time constant of the layer thickness regulating member in the voltage application circuit is sufficiently larger than 1 / (2πf). Even when the thickness regulating member discharges, it does not leak directly between the layer thickness regulating member and the developer carrier, so that a stable developer layer can be formed. Further, the developer can be stably charged by the discharge.

According to the tenth aspect, in the axial direction of the developer carrying member, the layer thickness regulating member portion is opposed to a region outside the region for carrying the developer on the developer carrying member. Is configured so as to have a larger electrical resistance than a portion facing the region where the developer is carried, so that the developer which is more likely to leak than the region where the developer is carried is carried. Leakage can be reliably prevented even in a non-existent area.

According to the eleventh aspect, the developer in the casing can be prevented from flowing out from the opening of the casing facing the latent image carrier by the outflow preventing member. Further, at least a contact portion of the outflow prevention member with the developer carrier is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the flow prevention member and the developing agent are formed. The surface of the dielectric material is frictionally charged to a polarity opposite to a predetermined charging polarity of the developer by friction between the agent carrier and the surface of the dielectric material. Can be done by

According to the twelfth aspect of the present invention, the contact portion of the outflow prevention member with the developer carrying member is made of a material which does not triboelectrically charge the developer or the developer has a polarity opposite to a predetermined charge polarity of the developer. It is made of a material that can be frictionally charged, and depending on the friction between the flow-down preventing member and the developer, the charge amount of the charged polarity of the developer is not increased or reduced, so that
The suction force between the undeveloped developer and the developer carrier is not increased or decreased, and thereby the filming due to the adhesion of the developer to the developer carrier is not increased or decreased by the flow-down preventing member. You can make it.

According to the thirteenth aspect of the present invention, an alternating electric field is formed between the outflow preventing member and the developer carrier by the voltage applying means, and the undeveloped developer on the developer carrier is removed. Since the alternating-current electric field oscillates between the flow-down preventing member and the developer carrying member to facilitate separation from the developer carrying member,
Replacement with a new developer can be promoted.

According to the fourteenth aspect of the invention, since the insulating material portion on the fixed end side of the outflow prevention member is brought into contact with the developer carrier, the developer in the casing flows from the opening of the casing to the outside. Can be prevented from flowing out. Further, an alternating portion is provided at an opposing portion between the conductive material portion located on the inner side of the casing and the developer carrier, which extends to the inner side of the casing than the contact portion of the flow-down preventing member with the developer carrier. Since the undeveloped developer on the developer carrier is vibrated by the electric field to promote the separation from the developer carrier, the replacement of the developer on the developer carrier can be further promoted.

According to the fifteenth aspect of the present invention, the outflow prevention member is formed of a plate-shaped member, and the outflow prevention member is attached to the developer carrier in a state of being bent and pressed. Accordingly, the working range of the alternating electric field can be regulated.

According to the sixteenth aspect, the first aspect,
In the developing device according to any one of 2, 7 and 13, the developer carrier may be one in which a dielectric portion and a grounded conductor portion are regularly or irregularly exposed on a surface with a small area. Since a small closed electric field is formed between the conductive portion and the charged portion, a large amount of developer can be carried. And in the developing device of claim 1 or 2,
When the developer vibrates due to the alternating electric field between the layer thickness regulating member and the developer carrier, the micro-closed electric field also acts to promote the contact between the dielectric portion of the developer carrier and the developer. Therefore, in the developing device using the dielectric portion for frictionally charging the developer, the charging of the developer can be further promoted and the filming due to the fixation of the developer to the developer carrier can be prevented. In particular, in the developing device according to the seventh aspect, since the charge of the discharge from the layer thickness regulating member can be used to charge the dielectric portion, the formation of a minute closed electric field can be stabilized. Further, in the developing device according to the thirteenth aspect, an undeveloped developer on the developer carrier is peeled off by an alternating electric field formed at a portion where the flow prevention member and the developer carrier are opposed to each other,
This prevents the developer from sticking due to the strong developer suction force of the minute closed electric field, thereby preventing filming of the developer.

According to the seventeenth aspect of the present invention, an alternating electric field is formed between the layer thickness regulating member and the developer carrier to vibrate the developer passing through the opposing portions of both members. A uniform developer layer can be formed on the developer carrier having passed through. Further, a free end of the layer thickness regulating member to which a voltage for forming an alternating electric field is applied is located at a facing portion between the developer carrier and the latent image carrier, and the free end of the facing portion is located at the free end. Since an alternating electric field is also formed between the portion and the latent image carrier, even if unnecessary developer scatters from the developer carrier, the developer is returned to the layer thickness regulating member side by the alternating electric field. , And can be returned to the developer carrier. here,
Since the developer carrier is disposed so as to oppose the surface of the latent image carrier from below, the collection of unnecessary developer to the developer carrier can also utilize the fall of the developer by its own weight. .
That is, unnecessary scattering of the developer from the developer carrier can be effectively prevented. Therefore, in the portion facing the latent image carrier, the developer on the developer carrier is powder-clouded by the alternating electric field, and, for example, by a DC electric field formed between the developer carrier and the latent image carrier, Also in the case of flying development, it is possible to prevent the developer from being scattered and to achieve the stability over time of the developing performance.

According to an eighteenth aspect of the present invention, in the developing device according to the seventeenth aspect, at least a portion of the developer carrier which is located at the facing portion is formed by laminating a medium resistance material and an insulating material; Since the surface of the insulating material is disposed so as to face the latent image carrier, and a discharge is unlikely to occur between the latent image carrier and the latent image carrier, a layer thickness regulating member is provided. The disturbance of the latent image on the latent image carrier due to the discharge can be reduced or prevented even when a predetermined voltage is applied.

According to the nineteenth aspect of the present invention, in the developing device of the eighteenth aspect, the layer thickness is set so that the time constant of the insulating material in the voltage application circuit is sufficiently larger than 1 / (2πf). A regulating member is provided, and thereby, the layer thickness regulating member is provided with a sufficient withstand voltage so as to prevent discharge from occurring with the latent image carrier, so that a predetermined voltage is applied to the layer thickness regulating member. However, disturbance of the latent image on the latent image carrier due to the discharge can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a copying machine according to an embodiment.

FIG. 2A is an explanatory diagram of an example of a blade contact in a developing device of the copying machine. (B) is an explanatory view of another example of the blade contact.

FIG. 3A is an explanatory diagram of toner behavior in the example of FIG. 2A. FIG. 2B is an explanatory diagram of the behavior of the toner in the example of FIG.

FIG. 4A is a schematic configuration diagram of a main part of a developing device according to another embodiment. (B) is a partially enlarged view of the developing device.

FIG. 5 is an explanatory diagram of a toner behavior near a seal blade of the developing device.

FIG. 6A is a partial perspective view of a developing device according to still another embodiment. FIG. 2B is a partial cross-sectional view of a developing roller surface of the developing device.

FIG. 7A is a schematic configuration diagram of a main part of a copying machine according to another embodiment. 3B is an explanatory diagram of a behavior of the toner in the developing device of the copying machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 3 Developing device 7 Casing 8 Developing roller 9 Blade 9a Conductive layer 9b Insulating layer 10 Agitator 11 Developing bias power supply 12 Blade bias power supply 13 Seal blade 13a Insulator portion 13b Conductor portion 14 Seal blade bias power supply 15 Dielectric portion E Alternating electric field E0 Small closed electric field I Entrance wedge X Exit wedge

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[Procedure amendment]

[Submission date] December 4, 2001 (2001.12.
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

1. A partially exposed from an opening of the casing facing the latent image bearing member, a dielectric material capable of frictionally charged to a predetermined polarity at least partially developer surface, the one-component developer A developer carrier that moves to return to the inside of the casing after being carried and conveyed to a portion facing the latent image carrier;
A developing device having a free end that contacts a free end portion of the developer carrier that has returned into the casing to prevent the developer in the casing from flowing out of the opening; At least a contact portion of the prevention member with the developer carrying member is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the outflow preventing member and the developer carrying member are formed. A voltage application means for applying a voltage for forming an alternating electric field is provided, wherein the fixed end side of the outflow prevention member is formed of an insulating material, and the free end side is formed of a conductive material. The conductive material is attached to the developer carrying member so that the conductive material contacts the developer carrying member, and the conductive material portion extends further inward of the casing than the contact portion with the developer carrying member. The above voltage is applied to the part made of conductive material Developing apparatus is characterized in that pressure was.

2. The surface of a one-component developer, which is partially exposed from an opening of a casing facing a latent image carrier and is at least partially made of a dielectric material capable of frictionally charging the developer to a predetermined polarity. A developer carrier that moves to return to the inside of the casing after being carried and conveyed to a portion facing the latent image carrier;
A developing device having a free end that contacts a free end portion of the developer carrier that has returned into the casing to prevent the developer in the casing from flowing out of the opening; At least a contact portion of the prevention member with the developer carrying member is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the outflow preventing member and the developer carrying member are formed. A voltage applying means for applying a voltage for forming an alternating electric field is provided between the first and second members, and the outflow prevention member is formed of a plate-like member, and the outflow prevention member is pressed against the developer carrier to be curved. A developing device characterized by being attached by:

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005]

To achieve SUMMARY OF to the above objects, a first aspect of the invention, partially exposed from an opening of the casing facing the latent image carrier, a predetermined polarity at least partially developer A developer carrier made of a dielectric material capable of being triboelectrically charged, the surface of which carries a one-component developer and is conveyed to a portion facing the latent image carrier and then moves back into the casing; A developing device having a flow-out preventing member for bringing a free end portion into contact with the surface of the developer carrier returned into the casing to prevent the developer in the casing from flowing out of the opening; At least a contact portion of the member with the developer carrying member is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer. A voltage that forms an alternating electric field between Providing a voltage applying means for applying, the fixed end side of the outflow prevention member is formed of an insulating material, and the free end side is formed of a conductive material, and the portion made of the insulating material is formed on the developer carrier. The conductive material is attached so that the portion made of the conductive material extends further inward of the casing than the contact portion with the developer carrier, and the voltage is applied to the portion made of the conductive material. It is characterized by the following. According to a second aspect of the present invention, the surface is formed of a dielectric material which is partially exposed from an opening of the casing facing the latent image carrier and is at least partially made of a dielectric material capable of frictionally charging the developer to a predetermined polarity. A developer carrier that carries the developer and is conveyed to the portion facing the latent image carrier and then moves back into the casing; and a free end portion on the surface of the developer carrier that has returned into the casing. And a flow-out preventing member that contacts the developer to prevent the developer in the casing from flowing out of the opening. A voltage applying means for applying a voltage for forming an alternating electric field between the outflow prevention member and the developer carrying member, by forming the dielectric material to a polarity opposite to the charging polarity of the dielectric material. The outflow prevention member is provided in a plate-like portion. In constructed, is the flow out preventing member characterized in that the mounting in a curved state by pressing on the developer carrying member.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Deleted

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Deleted

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Deleted

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Deleted

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Deleted

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Deleted

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Deleted

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Deleted

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Deleted

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Deleted

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Deleted

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Deleted

[Procedure amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

[0019]

According to the first aspect of the present invention, the developer in the casing is prevented from flowing out from the opening of the casing facing the latent image carrier by the outflow preventing member. Then, at least a contact portion of the outflow prevention member with the developer carrier is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the flow prevention member and the developing agent are formed. By friction of the agent carrier with the surface of the dielectric material, the surface of the dielectric material is frictionally charged to a polarity opposite to a predetermined charging polarity of the developer. Then, an alternating electric field is formed between the outflow prevention member and the developer carrying member by the voltage applying means, and the undeveloped developer on the developer carrying member is removed from the flow preventing member and the developer carrying member. During this period, the alternating electric field vibrates to facilitate separation from the developer carrier, thereby facilitating replacement with a new developer. Then, the insulative material portion on the fixed end side of the outflow prevention member is brought into contact with the developer carrier to prevent the developer in the casing from flowing out of the casing through the opening. Then, a voltage for forming an alternating electric field is applied to the conductive material on the free end side of the flow-down preventing member, which extends deeper in the casing than the contact portion of the flow-down preventing member with the developer carrier. Thus, the undeveloped developer on the developer carrier is vibrated by an alternating electric field at an opposing portion between the conductive material portion located on the inner side of the casing and the developer carrier. Promotes peeling off.

[Procedure amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

According to the second aspect of the present invention, the outflow preventing member prevents the developer in the casing from flowing out of the opening of the casing facing the latent image carrier. Then, at least a contact portion of the outflow prevention member with the developer carrier is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the flow prevention member and the developing agent are formed. By friction of the agent carrier with the surface of the dielectric material, the surface of the dielectric material is frictionally charged to a polarity opposite to a predetermined charging polarity of the developer. Then, an alternating electric field is formed between the outflow prevention member and the developer carrying member by the voltage applying means, and the undeveloped developer on the developer carrying member is removed from the flow preventing member and the developer carrying member. During this period, the alternating electric field vibrates to facilitate separation from the developer carrier, thereby facilitating replacement with a new developer. The outflow prevention member is formed of a plate-shaped member, and the outflow prevention member is pressed against the developer carrier and attached in a curved state, whereby the action of the alternating electric field is performed according to the degree of bending. Be able to regulate the range.

[Procedure amendment 18]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Deleted

[Procedure amendment 19]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Deleted

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Deleted

[Procedure amendment 21]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Deleted

[Procedure amendment 22]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Deleted

[Procedure amendment 23]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Deleted

[Procedure amendment 24]

[Document name to be amended] Statement

[Correction target item name] 0050

[Correction method] Deleted

[Procedure amendment 25]

[Document name to be amended] Statement

[Correction target item name] 0051

[Correction method] Deleted

[Procedure amendment 26]

[Document name to be amended] Statement

[Correction target item name] 0052

[Correction method] Deleted

[Procedure amendment 27]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Deleted

[Procedure amendment 28]

[Document name to be amended] Statement

[Correction target item name] 0054

[Correction method] Deleted

[Procedure amendment 29]

[Document name to be amended] Statement

[Correction target item name] 0055

[Correction method] Deleted

[Procedure amendment 30]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Deleted

[Procedure amendment 31]

[Document name to be amended] Statement

[Correction target item name] 0057

[Correction method] Deleted

[Procedure amendment 32]

[Document name to be amended] Statement

[Correction target item name] 0058

[Correction method] Deleted

[Procedure amendment 33]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Deleted

[Procedure amendment 34]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Deleted

[Procedure amendment 35]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction contents]

[0061]

According to the invention of claim 1 according to the present invention, that the developer in the casing flows out from the opening of the casing facing the latent image carrier can be prevented by the outflow prevention member. Further, at least a contact portion of the outflow prevention member with the developer carrier is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer, and the flow prevention member and the developing agent are formed. The surface of the dielectric material is frictionally charged to a polarity opposite to a predetermined charging polarity of the developer by friction between the agent carrier and the surface of the dielectric material. Can be done by Then, an alternating electric field is formed between the outflow prevention member and the developer carrying member by the voltage applying means, and the undeveloped developer on the developer carrying member is removed from the flow preventing member and the developer carrying member. During this period, the vibration is caused by the alternating electric field so that the developer is easily separated from the developer carrier, so that replacement with a new developer can be promoted. Since the insulating material portion on the fixed end side of the outflow prevention member is in contact with the developer carrier, the developer in the casing can be prevented from flowing out of the casing through the opening. Further, an alternating portion is provided at an opposing portion between the conductive material portion located on the inner side of the casing and the developer carrier, which extends to the inner side of the casing than the contact portion of the flow-down preventing member with the developer carrier. Since the undeveloped developer on the developer carrier is vibrated by the electric field to promote the separation from the developer carrier, the replacement of the developer on the developer carrier can be further promoted.

[Procedure amendment 36]

[Document name to be amended] Statement

[Correction target item name] 0062

[Correction method] Change

[Correction contents]

According to the second aspect of the present invention, the developer in the casing can be prevented from flowing out from the opening of the casing facing the latent image carrier by the outflow preventing member. Also,
At least a contact portion of the outflow prevention member with the developer carrying member is formed of a material capable of frictionally charging the dielectric material to a polarity opposite to a predetermined charging polarity of the developer. The friction of the body with the surface of the dielectric material causes the surface of the dielectric material to be frictionally charged to a polarity opposite to a predetermined charging polarity of the developer, so that the initial charging of the surface of the dielectric material is performed by the flow-down preventing member. be able to. Then, an alternating electric field is formed between the outflow prevention member and the developer carrier by the voltage applying means, and the undeveloped developer on the developer carrier is
Since the alternating electric field oscillates between the flow-prevention member and the developer carrying member to facilitate separation from the developer carrying member, replacement with a new developer can be promoted. And
The outflow prevention member is formed of a plate-like member, and the outflow prevention member is pressed against the developer carrier and attached in a curved state, so that the working range of the alternating electric field can be restricted according to the degree of bending. .

[Procedure amendment 37]

[Document name to be amended] Statement

[Correction target item name] 0063

[Correction method] Deleted

[Procedure amendment 38]

[Document name to be amended] Statement

[Correction target item name] 0064

[Correction method] Deleted

[Procedure amendment 39]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Deleted

[Procedure amendment 40]

[Document name to be amended] Statement

[Correction target item name] 0066

[Correction method] Deleted

Claims (19)

[Claims] 1. A developing device having a developer carrier and a layer thickness regulating member for regulating a layer thickness of a one-component developer carried on the developer carrier, wherein at least the developer of the layer thickness regulating member is provided. The carrier contact portion is made of an insulating material, and a developer charged to a predetermined polarity is provided between the layer thickness regulating member and the developer carrier from the layer thickness regulating member to the developer carrier. And a voltage applying means for applying a voltage for forming an alternating electric field, on which a DC component for forming an electric field in a direction to cause the electric field is superimposed. 2. A developing device comprising a developer carrier and a layer thickness regulating member for regulating a layer thickness of a one-component developer carried on the developer carrier, wherein at least the developer of the layer thickness regulating member is provided. A voltage applying means for applying a voltage for forming an alternating electric field in which a DC component is superimposed between the layer thickness regulating member and the developer carrier; And a DC varying means for varying the DC component. 3. The method according to claim 1, wherein the layer thickness regulating member is brought into contact with the developer carrying member with a belly pad, and a minute amount is formed in the moving direction of the surface of the developer carrying member on the upstream and downstream sides of the belly pad. 3. The developing device according to claim 1, wherein the surface portions of both members are opposed to each other with a suitable gap. 4. The apparatus according to claim 1, wherein said layer thickness regulating member is constituted by a plate-like member, and said layer thickness regulating member is attached to said developer carrier in a state of being curved by being pressed. Developing device. 5. The surface of the layer thickness regulating member facing the developer carrier is made of a Si-based material, a PTFE-based material,
3. The developing device according to claim 1, wherein the developing device is formed of a synthetic material with a TFE-based material. 6. The method according to claim 1, wherein the surface of the layer thickness regulating member facing the developer carrier has a surface roughness of not more than 1/3 of the particle diameter of the developer. Developing device. 7. The developing device according to claim 1, wherein said applied voltage applied to said layer thickness regulating member is set to be equal to or higher than a discharge starting voltage from said layer thickness regulating member. 8. The developing device according to claim 1, wherein a peak-to-peak voltage of the alternating electric field is set to be twice or more of a direct current discharge starting voltage. 9. The developing apparatus according to claim 1, wherein the surface of the layer thickness regulating member facing the surface of the developer carrier or at least a part of the surface of the developer carrier is conductive. The developing device according to claim 1, wherein the layer thickness regulating member is configured such that a time constant of the thickness regulating member in the voltage application circuit is sufficiently larger than 1 / (2πf). Here, π is the pi, and f is the frequency of the alternating electric field. 10. The developer carrying member according to claim 1, wherein
The layer thickness regulating member portion facing the region outside the developer carrying region on the developer carrying member, so that the electric resistance becomes larger than the portion facing the region carrying the developer. 3. A structure according to claim 1, wherein
Developing device. 11. A one-component developer whose surface is partially exposed from an opening of a casing facing a latent image carrier and is at least partially made of a dielectric material capable of frictionally charging a developer to a predetermined polarity. A free end portion is brought into contact with the developer carrying member that moves and returns to the inside of the casing after being carried and conveyed to the portion facing the latent image carrying member, and the surface of the developer carrying member that has returned into the casing. And a flow-out prevention member for preventing the developer in the casing from flowing out of the opening, wherein at least a contact portion of the flow-out prevention member with the developer carrier is charged with a predetermined amount of the developer. A developing device characterized in that the dielectric material is formed of a material that can be frictionally charged to a polarity opposite to the polarity. 12. A method according to claim 11, wherein said contact portion is made of a material which does not frictionally charge the developer or a material which can frictionally charge the developer to a polarity opposite to a predetermined charge polarity of the developer. Developing device. 13. A developing device according to claim 11, further comprising a voltage applying means for applying a voltage for forming an alternating electric field between said outflow preventing member and said developer carrier. 14. The outflow prevention member has a fixed end side formed of an insulating material and a free end side formed of a conductive material, and a portion made of the insulating material comes into contact with the developer carrying member,
And a portion made of the conductive material is attached so as to extend deeper into the casing than a contact portion with the developer carrier, and the voltage is applied to the portion made of the conductive material. 14. The developing device according to claim 13, wherein: 15. The outflow prevention member comprises a plate-like member,
14. The developing device according to claim 13, wherein the outflow preventing member is attached in a curved state by being pressed against the developer carrier. 16. The developer carrier according to claim 1, wherein a dielectric portion and a grounded conductor portion are regularly or irregularly exposed on the surface with a small area. 2, 7 or 13 developing device. 17. A developing device having a developer carrier and a layer thickness regulating member for regulating a layer thickness of a one-component developer carried on the developer carrier, wherein the developer carrier is a latent image carrier. The layer thickness regulating member is arranged so that a free end contacting the developer carrier is located at an opposing portion between the developer carrier and the latent image carrier. Developing characterized in that the layer thickness regulating member is provided with voltage applying means for applying a voltage for forming an alternating electric field between the layer thickness regulating member and the developer carrier. apparatus. 18. A method according to claim 18, wherein at least a portion of said developer carrier which is located at said facing portion is formed by laminating a medium resistance material and an insulating material, and the surface of said insulating material faces said latent image carrier. 18. The developing device according to claim 17, wherein the developing device is arranged as follows. 19. The developing device according to claim 18, wherein said layer thickness regulating member is constituted such that a time constant of said insulating material in said voltage applying circuit is sufficiently larger than 1 / (2πf). apparatus. Here, π is the pi, and f is the frequency of the alternating electric field.