JPH08286504A - Developing device - Google Patents

Abstract

PURPOSE: To reduce a defect in an image caused by the vibration of a control electrode plate and its ununiform pressing against a developing sleeve by fixing the control electrode plate with a vibration preventing member. CONSTITUTION: The developing sleeve 81 is rotated to carry a developer to a developing area A. The end surface opposite to an electrode part of the control electrode plate 84 is fixed on the side of a developing device 8 with the vibration preventing member 91, to be abutted on a layer of the developer, on the upstream side of the developing area A. The vibration of the control electrode plate 84 is suppressed by the vibration preventing member 91 and the plate 84 can be uniformly pressed on the developing sleeve 81.

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 electrophotographic copying machine, and more particularly to a developing device for developing a high quality image by reducing vibration of a control electrode plate provided in the developing device.

[0002]

2. Description of the Related Art Conventionally, as one of developing devices used in electrophotographic copying machines, there is a developing device using a one-component developer made of magnetic toner. This developing device includes a developing sleeve, which is a cylindrical developer carrier, which is rotatably supported around an outer circumference of an annular magnet having N poles and S poles arranged in the circumferential direction, and an electrostatic charge on the outer surface. An image forming body on which a latent image is formed and which moves close to the outer peripheral surface of the developing sleeve is provided, and the developer is attached to the outer peripheral surface of the developing sleeve by the magnetic force of the inner annular magnet and conveyed in the rotating direction of the developing sleeve, In a region where the developing sleeve and the image forming body are close to each other, the developer attached to the developing sleeve is flying-adhered to the electrostatic latent image of the image forming body to perform the development.

After development, an electric field is applied from one side of a separately supplied sheet to transfer the visible toner image on the surface of the image forming body to the sheet, and then heat or pressure is applied to fix the toner image on the sheet. . Further, after the transfer, the excess developer attached to the developing sleeve is scraped off and reused. The developer is
There is a two-component developer that uses a two-component developer composed of a magnetic carrier and a non-magnetic toner in addition to the above-mentioned one-component developer.
The two-component developer is suitable for a color copying machine because it is not necessary to include a black or brown magnetic substance in the toner, a toner image having a clear color can be obtained, and the toner charge control is easy.

[0004]

However, in all of the above-mentioned conventional developing methods, since a developer comprising non-magnetic toner particles having an average particle size of about 10 μm is used, delicate lines or dots, or dark and light There is a problem that it is difficult to obtain a high-quality image that reproduces differences and the like. In order to obtain such high image quality, it is considered necessary to make the toner particles finer.

However, if the toner particles are fine particles having an average particle size of 10 μm or less, the following problems occur. The influence of the Van der Waals force is relatively large with respect to the Coulomb force at the time of development, and the adhesion between the image forming body and the toner becomes strong, so that so-called fog in which toner particles adhere to the background of the image background is also generated. Will occur. Further, it is difficult to prevent fogging even by applying a DC bias voltage to the developer transport body.

Friction charging control becomes difficult because the toner movement becomes poor. In addition, toner aggregation is likely to occur. In the two-component development method, the carrier coverage of the toner is increased due to the finer particles, and the toner covering the carrier and the toner on the outside thereof are less likely to be exchanged. The chargeability deteriorates. Therefore, it becomes more difficult to control charging.

When the carrier particles are made into fine particles to reduce the carrier coverage, the carrier particles also adhere to the electrostatic image portion of the image forming body. It is considered that this is because the magnetic bias force is reduced and the carrier particles adhere to the image forming body side together with the toner particles. Further, when the bias voltage becomes excessively high, carrier particles also adhere to the ground portion of the image background.

The fine particles of the toner and the carrier have the problem that the above-mentioned side effects are more noticeable and a clear image cannot be obtained. Therefore, the fine particles of the toner and the carrier should be formed in an actual developing device. Was difficult. As a method for solving the above problems, a plate-shaped control electrode plate having an electrode in the upstream portion of the developing area is brought into contact with a developer transport body, and the control electrode plate, the developer transport body, and the developer transport body. A control electrode method in which an oscillating electric field that makes the former stronger is formed between the image forming member and the image forming body, and the toner in the developer is clouded (clouded) to perform development is disclosed in Japanese Patent Laid-Open No. Hei 5- 3467
No. 36 and Japanese Patent Laid-Open No. 6-175485.

A similar control electrode method has been proposed for a one-component developer which does not use carrier particles, and a one-component toner cloud developing method suitable for small particle size toner is disclosed in Japanese Patent Laid-Open No. 6-175485. Has been done. However, in the above-mentioned reference example, the control electrode plate vibrates in accordance with the vibration in the apparatus and the movement of the developer transport body, and horizontal stripes, white spots and stepped unevenness are easily generated in the image.

Therefore, the present invention has been made in view of such conventional problems, and provides a developing device capable of stably obtaining a high quality image by preventing the vibration of the control electrode plate. The purpose is to do. Another object is to uniformly press the control electrode plate against the developer layer to further improve the image quality.

[0011]

According to a first aspect of the present invention, there is provided an insulating member, which is in contact with a developer layer, at a developing area of a developer carrier which faces an image forming body or at an upstream portion of the developing area. In a developing device having a control electrode plate provided with a supported electrode portion to which a voltage can be applied, the control electrode plate is fixed to the developing device via a vibration preventing member.

According to a second aspect of the invention, the vibration preventing material is a rubber elastic body. According to a third aspect of the present invention, the control electrode portion is disposed at one end portion of the control electrode plate, and an end portion of the control electrode plate on a side opposite to an electrode portion side is sandwiched by a vibration preventing member, The anti-vibration member is fixed to the developing device via fixing means for fixing the vibration preventing member so that the force in the sandwiching direction acts.

According to a fourth aspect of the present invention, the fixing means includes two members that sandwich the anti-vibration material in the sandwiching direction of the end portion of the control electrode plate, and a fastening member that fastens these two members together. I tried to be. In the invention according to claim 5, one of the two members is a flat plate member in contact with one surface of the vibration preventing member in the sandwiching direction, and the other is in contact with the opposite surface and the back surface of the vibration preventing member. The fastening member is fastened to these two members in the same direction as the sandwiching direction of the control electrode plate end of the vibration prevention member.

According to a sixth aspect of the present invention, the two members are
One is a leaf spring member having two surfaces forming an acute angle capable of contacting one surface of the vibration prevention member in the sandwiching direction and the back surface, and the other is a member contacting the opposite surface of the vibration prevention member. When the two members are fastened to each other, the two surfaces of the leaf spring member having an acute angle are expanded, and the reaction force urges the force in the sandwiching direction.

According to a seventh aspect of the present invention, the two members are
One of them is a flat plate member that comes into contact with one surface of the vibration prevention member in the sandwiching direction, and the other is a member that comes into contact with the opposite surface of the vibration prevention member, and the fastening member can be freely attached to and detached from the two members. It was formed so as to be locked. Claim 8
The invention described in (1), the anti-vibration material is provided on both surfaces of the end portion opposite to the electrode portion of the control electrode plate, and a pressing member is provided on each surface of the anti-vibration material opposite to the surface in contact with the control electrode plate. The control electrode plate, the vibration preventive material, and the pressing member are sandwiched by an elastically biased fastening member, so that the control electrode plate, the vibration preventive material, and the fixing member are pressure-bonded to each other. Was fixed to the fixed side.

According to a ninth aspect of the invention, the control electrode plate is fixed to the developing device by adhesion via a vibration preventing member. According to a tenth aspect of the invention, an electrode portion is formed on the upper surface of one end of the control electrode plate, and the outer peripheral portion of the electrode portion exposed to the outside is covered with an electrode covering member.

In the eleventh aspect of the present invention, an electrode portion is formed on the upper surface of one end of the control electrode plate, and a flat plate-shaped electrode covering member is further provided on the upper surface of the electrode portion.

[0018]

According to the first aspect of the present invention, the control electrode plate is fixed to the fixed side via the anti-vibration material, so that the vibration of the control electrode plate is reduced during development and the image deterioration caused by the vibration is reduced. Can be made. In the invention described in claim 2, by using the rubber elastic body as the vibration preventing material, the vibration of the control electrode plate can be easily attenuated with a simple configuration. Further, due to the elastic characteristic of the vibration preventing member, it is possible to disperse the local pressing force generated at the mounting portion of the control electrode plate. As a result, the control electrode plate can be pressed against the developer transport body with a uniform pressure.

According to a third aspect of the present invention, the end portion of the control electrode plate opposite to the electrode portion is sandwiched between the vibration preventing members,
The vibration preventing member can be fixed to the developing device by means of a fixing means for fixing the vibration preventing member so that the force in the sandwiching direction acts. In the invention according to claim 4, the anti-vibration member is fixed to the developing device by two members that sandwich the anti-vibration material in the sandwiching direction of the end portion of the control electrode plate and a fastening member that fastens these two members together. be able to.

According to the fifth aspect of the invention, one of the flat plate member is in contact with one surface of the vibration prevention member in the sandwiching direction, and the other is a member in contact with the opposite surface and the back surface of the vibration prevention member. The two configured members can be fastened together by the fastening member in the same direction as the sandwiching direction of the control electrode plate of the vibration prevention member with a simple configuration. According to a sixth aspect of the present invention, one has a leaf spring member having two acute-angled surfaces capable of contacting one surface in the sandwiching direction of the vibration prevention member and the back surface, and the other is the opposite of the vibration prevention member. By the two members formed by the member that contacts the side surface, the two surfaces having the acute angle of the leaf spring member are expanded and pressed against the two surfaces of the vibration prevention member, and the reaction force causes the force in the sandwiching direction. Since it is biased, the vibration preventing member can be more reliably fixed.

According to a seventh aspect of the present invention, the two members are
One of them is a flat plate member that comes into contact with one surface of the vibration prevention member in the sandwiching direction, and the other is a member that comes into contact with the opposite surface of the vibration prevention member, and the fastening member can be freely attached to and detached from the two members. By forming it so as to be locked, the vibration preventing member can be easily fixed. According to an eighth aspect of the present invention, the vibration-preventing material is provided on both surfaces of an end portion of the control electrode plate opposite to the electrode portion, and the vibration-preventing material is provided on each surface opposite to the surface in contact with the control electrode plate. Arrange a pressing member,
By sandwiching the control electrode plate, the anti-vibration material, and the pressing member with a fastening member that is elastically biased, the control electrode plate, the anti-vibration material, and the fixing member are crimped,
The fastening member can be more securely fixed to the fixed side.

According to the ninth aspect of the invention, the control electrode plate can be fixed with a simple structure by adhering the control electrode plate to the developing device via the vibration preventing member.
According to a tenth aspect of the present invention, an electrode portion is formed on the upper surface of one end portion of the control electrode plate, and the outer peripheral portion of the electrode portion exposed to the outside is covered with an electrode covering member to form a developing member. It is possible to reduce the contamination of the electrode portion at the time.

The invention described in claim 11 has a simple structure by forming an electrode portion on the upper surface of one end of the control electrode plate and further providing a flat plate-shaped electrode covering member on the upper surface of the electrode portion. It is possible to reduce contamination of the electrode portion.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows a schematic configuration of a color image forming apparatus including a developing device. In FIG. 4, a photosensitive belt 1 (image forming body), which is a flexible belt coated or vapor-deposited with a photoconductor, is installed between rotating rollers 2 and 3 and is driven by the rotating roller 2 to drive the timepiece. Is conveyed in the direction. The guide member 4 is fixed to the main body of the developing device so as to be inscribed in the photoconductor belt 1, and the photoconductor belt 1 is tensioned by the action of the tension roller 5, so that the inner peripheral surface of the guide member 4 is fixed to the guide member 4. Rub against. The photosensitive belt 1 is charged by a scorotron charger 6 and image information is written by a laser writing device 7 using a laser beam. Development is performed by attaching a developer toward the latent image formed on the photosensitive belt 1 by this writing. This developing device is provided for each color component, and also includes a plurality of developing devices 8A, 8B, 8C, 8D according to the present invention, each containing a developer of a specific color. Each of the developing devices is arranged in a portion of the photoconductor belt 1 that is in contact with the guide member 4.

Although the details of the developing devices 8A to 8D will be described later, their constructions contain, for example, yellow, magenta, cyan, and black developers, respectively, and form a predetermined gap with the photosensitive belt 1. Keep each developing sleeve 81
The developing sleeve 81 of each of the developing devices 8A, 8B, 8C and 8D is applied with a bias voltage of direct current or further alternating current so that the latent image on the photosensitive belt 1 is not contacted by the reversal developing method. Can be visualized with. This non-contact development has an advantage that it does not hinder the movement of the photosensitive belt 1 unlike contact development.

A transfer device 12 is provided on the side of the rotary roller 2 of the photosensitive belt 1, and a cleaning device 13 is provided on the side of the rotary roller 3. The blade 13a and the toner discharge roller 13b of the cleaning device 13 are kept at a position separated from the surface of the photoconductor belt 1 during image formation, and the surface of the photoconductor belt 1 is only shown at the time of cleaning after image transfer as shown in the figure. Is pressed against.

The process of forming a color image by such a color image forming apparatus is performed as follows. (B) Color image data is obtained by an image data input unit or the like that scans the image sensor on the original image. (B) The color image data is arithmetically processed by the image data processing unit so as to be stored in the memory.

(C) The processed image data is temporarily stored in the image memory. (D) When recording (printing) this input image data, it is input to the color image forming apparatus of FIG. In this color image forming apparatus, an image is formed as follows.
That is, when image data, which is a color signal and a luminance signal output from a separate image reading device, is input to the laser writing device 7, in the laser writing device 7, it is generated by a semiconductor laser which is a writing light source (not shown). The laser beam (writing light) passes through a collimator lens and a cylindrical lens (not shown), is rotationally scanned by a rotary polygon mirror 74 rotated by a noise motor 71, passes through an fθ lens 75 and a cylindrical lens 76, and two beams in between. The main scanning performed by projecting onto the peripheral surface of the photoconductor belt 1 whose optical path is bent by the mirrors 77 and 78 of FIG. Raster scanning is performed by sub-scanning due to movement to form a latent image.

On the other hand, when the scanning is started, the laser beam is detected by an index sensor (not shown), and the first
The laser beam modulated by the color signal of (1) scans the peripheral surface of the photosensitive belt 1. Therefore, by the main scanning by the laser beam and the sub-scanning by the conveyance of the photosensitive belt 1,
A latent image corresponding to the first color is formed on the peripheral surface of the photosensitive belt 1. This latent image is first developed by the developing device 8A loaded with yellow toner (visual medium) in the developing means, and the toner adheres to the surface of the photosensitive belt 1 to form a toner image. The obtained toner image passes under the blade 13a and the toner discharge roller 13b of the cleaning device 13 which is kept away from the peripheral surface of the photosensitive belt 1 while being held on the surface of the photosensitive belt 1, and the next image is formed. Enter the cycle.

That is, the photoconductor belt 1 has the charger 6
Is charged again, and then the second color signal is input to the laser writing device 7, and writing is performed on the belt surface in the same manner as in the case of the first color signal described above to form a latent image. The latent image is developed by the developing device 8B loaded with magenta toner as the second color. This magenta toner image is formed in the presence of the previously formed yellow toner image.

Then, as the third color, the developing device 8C having a cyan toner forms a cyan toner image on the belt surface in the same manner as the first and second colors. Finally, a developing device 8D having a black toner forms a black toner image on the surface of the belt in the same manner as the above-described color processing. The toner image composed of yellow, magenta, cyan, and black thus formed on the peripheral surface of the photoconductor belt 1 is fed from the paper feed cassette 14 by applying a high voltage having a polarity opposite to that of the toner at the transfer portion. It is transferred to the transfer material sent through the paper guide 15.

One of the uppermost layers of the transfer material contained in the paper feeding cassette 14 is carried out by the rotation of the paper feeding roller 16,
It is supplied to the transfer device 12 via a timing roller 17 in synchronism with the image formation on the photosensitive belt 1. After the transfer of the toner image is transferred, the transfer material is surely separated from the photosensitive belt 1 which suddenly changes its direction along the rotating roller 2 and faces upward, and after the toner image is welded and fixed by the fixing roller 18. Then, the paper is discharged onto the tray 20 via the paper discharge roller 19.

On the other hand, the photosensitive belt 1 which has been transferred to the transfer material is further conveyed, and the residual toner is removed by the cleaning device 13 in which the blade 13a and the toner discharge roller 13b are in pressure contact with each other. After that, the blade 13a and the toner discharge roller 13b are separated again to start a new color image forming process. As such a color image forming apparatus, a belt-shaped image forming body has been described, but the developing device according to the present invention can be similarly used for an image forming apparatus having a drum-shaped image forming body.

The developing devices 8A to 8D have the same structure, and the developing device contains a two-component developer and a one-component developer, and any developing device can be used. . Hereinafter, a developing device containing a two-component developer is denoted by reference numeral 8, and a developing device containing a one-component developer is denoted by reference numeral
I will show it in 8a. FIG. 1 is a schematic sectional view of a developing device for a two-component developer showing a first embodiment of the developing device according to the present invention. 1 and 2 are a schematic sectional view and an enlarged sectional view of an essential part of this embodiment, and FIG. 3 is a diagram showing another example of a bias power supply.

A developing sleeve 81, which is a developer carrier made of a non-magnetic material such as aluminum, is rotatable in the direction of the arrow in the drawing, and a plurality of N / S magnetic poles are circumferentially arranged inside the developing sleeve 81. The magnet body 82 it has is fixed. In particular,
The one disposed in the developing area A at the closest position between the developing sleeve 81 and the photosensitive belt 1 will be referred to as a main magnetic pole.
In this figure, one magnetic pole 82a of the magnet body 82 becomes the main magnetic pole.
By rotating the developing sleeve 81 around the magnet body 82, the developer can be conveyed by the magnetic force of the magnet body 82. Each magnetic pole including the main magnetic pole 82a of the magnet body 82 is 500
It is magnetized to a magnetic flux density of ˜1500 gauss, and the magnetic force forms a layer of magnetic developer D, that is, a magnetic brush, on the developing sleeve 81. This magnetic brush has a developing sleeve 81
Is rotated to move on the peripheral surface of the developing sleeve 81 and is conveyed to the developing area A. The developing sleeve 81 and the regulation blade 86
And the gap between the developing sleeve 81 and the photosensitive belt 1 are adjusted in advance so that the magnetic brush formed on the developing sleeve 81 does not contact the surface of the photosensitive belt 1.

A control electrode plate 84 is provided on the upstream side of the developing area A so as to contact the layer of the developer D. The control electrode plate 84 includes an insulating support member 83 made of an electrically insulating material.
An electrode portion 84a capable of applying a voltage to the upper surface of the end portion of the insulating support member 83, and a covering member 84d covering the electrode portion 84a.
It is formed by and. Here, the electrode portion 84a is made of a conductive material such as metal, and is linearly provided integrally on the tip portion of the insulating support member 83.

A stirring screw 85 embedded in the developer D
A and 85B stir the developer D to make the components uniform and to charge the toner by friction with the carrier. A regulating blade 86 made of a non-magnetic material or a magnetic material regulates the height and amount of the magnetic brush, and the cleaning blade 87 has a developing area A.
It is provided to remove from the developing sleeve 81 the magnetic brush that has passed through. Further, the developer is stored in a developer reservoir 88 formed in the casing 89, and the control electrode plate 84 is fixed to a supporting portion 89a provided in the casing 89 by a holding plate 90 and a set screw 90s. The anti-vibration agent 91 is formed of, for example, urethane rubber having a rubber hardness of 50 ° for suppressing the vibration of the control electrode plate 84 and pressing the control electrode plate 84 against the developing sleeve with a uniform pressure.

As shown in FIG. 2, the control electrode plate 84 is installed at a position upstream of the developing area A with respect to the rotation direction of the developing sleeve 81, and the following conditions are set.
It is preferable in order to improve the sharpness of the developer D and maintain the development efficiency at a high level to prevent the toner from scattering. The angle between the closest position 81a of the developing sleeve 81 with respect to the photosensitive belt 1 and the main magnetic pole 82a about the rotation axis O of the developing sleeve 81 is θ ₁ , and the closest position 81a and the control electrode plate 84 are also the same. If the angle with the tip is θ ₄ (the value of the angle is positive on the upstream side of the closest position 81a and negative on the downstream side), −10 ° ≦ θ ₁ ≦ 10 ° (1 ) is preferably _{(θ 1 -5 °) ≦ θ} 4 ≦ (θ 1 + 5 °) ··· (2).

If θ ₁ is less than −10 ° or greater than 10 °, the spike of the developer D in the developing area A is deteriorated and the developability is deteriorated. Also, θ ₄ is (θ ₁ −5
If it is smaller than (°), the control electrode plate 84 covers too much the spiked portion of the developer D and the developability is lowered, and θ ₄ is (θ ₁ +5).
If it is larger than 0 °, the spikes of the developer D become too large, and the developer D comes into contact with the photoconductor belt 1, causing blemishes and carrier adhesion to cause image disturbance.

In this way, the main magnetic pole 82a is provided in the developing area A.
Then, the control electrode plate 84 is arranged in the vicinity thereof and the developer D layer is pressed.
By holding it, the ears of developer D are made to rise properly and carry
Application of low development bias voltage without causing adhesion
Can improve the developability. But the control electrode
Since the installation position of the plate 84 is on the upstream side of the developing area A,
Station θ _FourIs 0 ° <θ_Four≤ (θ₁ + 5 °) ... (3) is preferable.

When the developer D is conveyed onto the developing sleeve 81, the developer D enters between the insulating support member 83 and the developing sleeve 81 as shown in FIGS.
84 is slightly curved so that the insulating support member 83 faces the developing sleeve 81 with a slight gap or has almost no gap,
That is, the developing sleeve 81 and the developing sleeve 81 are opposed to each other.

In the above construction, the bias voltage in which the AC component is superimposed on the DC component is applied to the developing sleeve 81 by the DC bias power source E ₁ and the AC bias power source E ₂ through the protective resistor R ₁ . Further, the electrode portions 84a bias voltage only a DC component is applied via a protective resistor R ₂ from the DC bias power source E _3. It is preferable to apply a DC voltage having the same polarity as the toner in the developer to the electrode portion 84a from the viewpoint of preventing toner adhesion.

When the DC voltage applied to the developing sleeve 81 is equal to the DC voltage applied to the electrode portion 84a, the DC bias power source E ₁ can be shared as shown in FIG. 3, and the apparatus is complicated. Can be avoided. In the developing device 8 in the first embodiment, the control electrode plate is formed together with the alternating electric field (second oscillating electric field) 93 formed between the photosensitive belt 1 and the developing sleeve 81 by the above bias voltage application.
A first oscillating electric field 94 is generated between the electrode portion 84a of 84 and the developing sleeve 81. In this case, the electrode part 84
Since a is provided closer to the developing sleeve 81 than the photosensitive belt 1, the strength of the first oscillating electric field is larger than the strength of the second oscillating electric field.

Further, due to the first oscillating electric field, the developer D which has reached the vicinity of the electrode portion 84a in the direction perpendicular to the line of electric force thereof.
Since the toner particles are vibrated, it is possible to separate and fly the toner particles from the carrier and sufficiently generate a haze-shaped toner cloud. This toner cloud is second
The oscillating electric field assists the flight toward the latent image on the photoconductor belt 1, and thus uniform development can be performed.

At this time, since the AC bias is applied only to the developing sleeve 81, the first oscillating electric field and the second oscillating electric field have the same phase, and the toner particles are oscillated from the first oscillating electric field to the second oscillating field. It can be smoothly transferred to the electric field.
The waveform of the AC component is not limited to a sine wave, and may be a rectangular wave or a triangular wave. Under a certain frequency, the higher the voltage value, the more the magnetic brush of the developer D is vibrated, and the toner particles are easily separated from the carrier particles and fly. However, on the other hand, there is a drawback that dielectric breakdown such as fog and discharge phenomenon is likely to occur.

The occurrence of the fog can be prevented by reducing the DC bias component, and the dielectric breakdown is caused in the developing sleeve.
This can be prevented by insulating or coating the surface of 81 with a resin, an oxide film, or the like, or by using insulating carrier particles as described below as the carrier particles of the developer D. In the color image forming apparatus using this embodiment, a negatively charged OPC (Organic photo-conducer) is used as the photoconductor of the photoconductor belt 1.
reversal development is performed by using a photoconductor, the photoconductor is charged to, for example, -850 V, and the potential of the maximum density portion of the image is -5.
In the case of 0V, it is preferable to apply a bias voltage of −750V to the electrode portion 84a and a bias voltage of −750V to the developing sleeve 81, in which an AC voltage is superimposed on a DC voltage.

Here, a zero peak voltage V representing the maximum amplitude of the AC bias component applied to the developing sleeve 81.
_As shown in FIG. 1, _0-P is the closest distance d ₁ (mm) between the image forming body 1 and the developing sleeve 81, the height d ₂ (mm) of the electrode portion 84a from the developing sleeve, and the developer. Toner volume average particle size
dt (μm), where the average charge amount of the toner is Q ₂ (μC / g), 3Q ₂ dt d ₂ <V _0-P <20Q ₂ dt d ₁ (4) In particular, 5Q ₂ The range of dt d ₂ <V _0-P <10Q ₂ dt d ₁ (5) is preferable. Here, the average charge amount Q ₂ of the toner is such that a conductive plate of 2 cm × 5 cm is opposed to a developing roller having a diameter of 20 mm at a closest distance of 0.7 mm, and a developer is supplied to the developing roller while rotating at 350 rpm. A superimposed voltage of DC and AC (for example, DC voltage 1000V, AC zero peak voltage 750V _0-P , AC frequency 8kHz) is applied to the developing roller to develop the toner in the developer on the conductive plate, This is a value obtained by connecting a conductive plate on which this toner has been developed to a Faraday gauge, blowing the toner off with nitrogen gas, and measuring the charge amount and the weight of the toner blown off at this time.

Further, d ₂ is preferably (0.2 to 0.6) d ₁ from the viewpoint of preventing discharge to the developing sleeve and the image forming body and securing the developing property, and the frequency of the applied AC component is 100 Hz to 20 kHz, particularly 1 kHz. It is preferably -10 kHz. 5 and 6
FIG. 3A is a perspective view and an enlarged sectional view showing an example of a control electrode plate 84. The control electrode plate 84 shown in FIG. 5 uses a conventionally known printed circuit board manufacturing method, and as the insulating support member 83 (substrate), for example, polyester, polyimide, glass epoxy, ethylene-4 fluoride ethylene copolymer, tetrafluoride is used. Ethylene-6
Resin materials such as propylene fluoride copolymer, polytetrafluoroethylene, polyamideimide, polysulfone, triazine resin and polyethylene terephthalate, and inorganic materials such as glass fiber reinforced resin, ceramics, glass and alumina can be used.

Electrolytic copper foil, annealed electrolytic steel foil, beryllium steel foil, and the like are attached to these insulating support members 83 by an adhesive agent, and the photoetching method using a conventionally known photopolymer and the etching resist forming method by screen printing are used. The necessary electrode portion 84a is formed on the insulating support member 83. In addition, a method of printing a conductive ink corresponding to the electrode portion 84a with a relief printing plate, a stencil printing plate, an intaglio printing plate, or a metal deposition method can be used. Further electrode part 84
In order to prevent unnecessary discharge from a, it is preferable to form a covering member 84d which is an insulating layer on the electrode portion 84a, and this covering member 84d can be made of the same material as the insulating supporting member 83. . A method of applying an insulating ink instead of the covering member 84d can also be used.

Further, the control electrode plate shown in FIGS.
Besides 84, for example, the shape and connection method of the electrode portion 84a and the insulating support member 83 shown in FIGS. In FIG. 7, an electrode portion 84a having a circular cross section is arranged on the insulating support member 83, and in FIG. 8, an electrode portion 84a having a rectangular cross section is arranged. Figure 9
Is provided with a cutout 83a in the insulating support member 83, and the cutout
An electrode portion 84a having a circular cross section is disposed in 83a, and in FIG. 10, an electrode portion 84a having a rectangular cross section is disposed in the cutout portion 83a. FIG. 11 shows that the insulating support member 83 is provided with a groove portion 83c
An electrode portion 84a having a circular cross section is disposed in 83c, and in FIG. 12, an electrode portion 84a having a rectangular cross section is disposed in the groove portion 83c. Figure
13 is an electrode portion 84 having a circular cross section on the upper surface of the end of the insulating support member 83.
a is provided, and in FIG. 14, an electrode portion 84a having a rectangular cross section is provided on the upper surface of the end portion of the insulating support member 83. In FIG. 15, a plate-shaped electrode portion 84a is provided on the upper surface of the end of the insulating support member 83, and in FIG. 16, a plate-shaped electrode portion 84a is provided on the upper surface of the end of the insulating support member 83. Further, a covering member 84c which is an insulating support member is arranged on the upper surface of the electrode portion 84a.

As shown in FIG. 1, the control electrode plate 84 is fixed to the developing device via the vibration preventing material 91. As a method of fixing the control electrode plate 84, for example, the method shown in FIGS. Conceivable. In FIG. 17, the control electrode plate 84 is sandwiched between the vibration preventing members 91 provided on the supporting portion 89a, and the set screw 90s is passed through the vibration preventing member 91 via the holding plate 90 and fastened to the supporting portion 89a. FIG. 18 shows a control electrode plate 84 supporting portion similar to FIG.
89a Scissors into the anti-vibration material 91 and supports it on the outside of the anti-vibration material 91 with the holding screw 90 and the set screw 90s.
It is concluded with 89a. In FIG. 19, the control electrode plate 84 is fixed to the vibration preventing material 91 provided on the supporting portion 89a with an adhesive or the like. FIG. 20 shows that the control electrode plate 84 is sandwiched between the anti-vibration members 91 provided on the supporting portions 89a, and the anti-vibration members 91 are covered at one end by a leaf spring member 92 such as a phosphor bronze plate having a bent portion with an acute angle. The control electrode plate 84 is fixed by fastening the supporting portion 89a and the leaf spring member 92 with the set screw 90s at the other end. 21. As in FIG. 20, the control electrode plate 84 is scissored into the vibration preventing material 91 provided on the supporting portion 89a, and the leaf spring member 92 is formed.
Cover the anti-vibration material 91 at one end and set screw at the other end.
90s support plate 89a and leaf spring member via holding plate 93
The control electrode plate 84 is fixed by fastening with 92. In FIG. 22, the control electrode plate 84 is sandwiched between the vibration preventing members 91 provided on the support portion 89a, and is fixed to the support portion 89a by the buckle-shaped metal fitting 94 via the holding plate 90. FIG. 23 is a side view of FIG. In FIG. 24, the control electrode plate 84 is covered with the vibration preventing material 91, and pressing plates 96 are provided on both outer sides of the control electrode plate 84. It is sandwiched and fixed to the support portion 89a.

Here, as the vibration preventing material 91, foam such as cork, felt, urethane foam, polymer gel such as silicone gel, natural rubber, synthetic rubber and the like are preferable, but among them, vibration is sufficiently absorbed, In order to reduce the local pressing force and bias of the control electrode plate mounting portion, rubbers represented by polymer gels having a small Young's modulus and rubber-like elasticity, natural rubbers, and synthetic rubbers are particularly preferable. These rubber elastic bodies have two effects of (a) dispersing the local pressing force of the control electrode plate mounting portion, and (b) absorbing the vibration transmitted from the developing device and preventing the vibration of the electrode plate. .

Examples of these rubber elastomers preferably used are latex, raw rubber, styrene-butadiene rubber, isoprene rubber, butyl rubber, nitrile rubber,
Ethylene / propylene rubber, chlorosulphonated polyethylene, acrylic rubber, urethane rubber, silicone rubber,
Fluorine rubber, polysulfide rubber, epichlorohydrin rubber, propylene oxide rubber, alfin rubber, silicone gel and the like can be mentioned.

The hardness of these rubbers (JIS-A) is 30 ° to 80
°. In particular, 40 ° to 70 ° is preferable, and if it is less than 30 °, the permanent strain shown in JIS K6301 becomes large, so that it does not show rubber elasticity when used for a long period of time.
Transport irregularities will occur. If it is larger than 80 °, elastic deformation is less likely to occur, and it becomes difficult to make the pressing force uniform.

Next, the carrier used for the developer will be described. Generally, when the average particle size of the magnetic carrier particles is large, the state of the brush of the magnetic brush formed on the developing sleeve 81 becomes rough, so that even if the electrostatic latent image is developed while applying an oscillating electric field, the toner image becomes uneven. Tend to appear, and the toner concentration at the ears becomes low. Therefore, there arises a problem that high density development is not performed.

In order to solve this problem, the average particle size of the magnetic carrier particles may be reduced, and as a result of experiments, the above problems occur when the volume average particle size is 10 to 60 μm, preferably 20 to 50 μm. It turned out not to. When the thickness is less than 10 μm, it is difficult to magnetize the carrier sufficiently, and the particles are attached to the surface of the photosensitive belt 1 together with the toner particles, and the carrier is easily scattered. On the other hand, when it is larger than 60 μm, the specific surface area of the carrier becomes small, so that the toner cannot be sufficiently charged. Further, since the coverage ratio of the toner covering the carrier is high, the toner not in contact with the carrier around the carrier is easily scattered, and the toner in contact with the carrier is not sufficiently charged, so that the carrier moves It peels off from the surface of the carrier, and toner scattering easily occurs.

The volume average particle size is measured by a laser diffraction type particle size distribution measuring apparatus "HEROS" (SYMPAT) equipped with a wet dispersion machine.
It was measured by EC). First, use a wet disperser to disperse 10 mg of magnetic particles in 50 mg of water together with a surfactant, and then use an ultrasonic homogenizer (output 150 W), taking care not to cause re-aggregation due to heat generation. It is a value measured after the treatment.

The strength of magnetization of carriers (maximum magnetization) is 5
-60 emu / g, preferably 10-40 emu / g. This strength depends on the magnetic flux density on the developing sleeve 81, but under the general magnetic flux density of the developing sleep 81 of 500 to 1200 gauss, the magnetic binding force does not work at less than 5 emu / g. It may cause carrier scattering. If it exceeds 60 emu / g, the spikes of the carrier become too high, and it becomes difficult to maintain the non-contact state with the photosensitive belt 1.

Here, the magnetization intensity of the carrier is determined by tapping carrier particles into a sample cell of 0.25 cm × 3 cm, filling the sample cell with a pickup coil and setting the sample on a magnetizer, and then a DC magnetization characteristic automatic recording apparatus. It was obtained by drawing a hysteresis curve on an XY recorder using "TYPE3227", (manufactured by Yokogawa Hokushin Electric Co., Ltd.). Such a magnetic carrier is made of iron, which is the same as a conventional magnetic carrier as a magnetic body.
Chromium, nickel, cobalt and other metals, or their compounds and alloys, such as ferro-ferrous spherical bodies such as ferric tetroxide, γ-ferric oxide, chromium dioxide, manganese oxide, ferrate manganese-steel alloys Styrene-based resin, vinyl-based resin, ethyl-based resin, rosin-modified resin, acrylic-based resin, polyamide resin, epoxy-based resin, polyester-based resin, silicon-based resin , A fluorine-based resin or the like, or a spherical coating with a copolymer.

Further, a so-called resin dispersion type carrier in which magnetic fine particles are dispersed and contained in these resins can also be used. In this case, since the carrier has an irregular shape, the specific surface area increases, and a sufficient amount of toner necessary for development can be obtained with a lower surface coverage.
Therefore, toner scattering is less likely to occur and stable development can be performed.

Next, the toner particles will be described. Generally, when the average particle size of the toner particles becomes small, the charge amount decreases in proportion to the square of the particle size. As a result, the adhesive force due to the Van der Waals force is relatively increased and the particles are easily scattered, which may cause fog. Further, it becomes difficult for the toner to separate from the carrier particles of the magnetic brush.

In the conventional magnetic brush developing method, this problem becomes noticeable when the average particle diameter of the toner is smaller than 10 μm. In the developing device of this embodiment, this problem was solved by developing under the double oscillating electric field by the magnetic brush. On the other hand, when the volume average particle diameter of the toner is larger than 20 μm, the image roughness becomes conspicuous as described above. Furthermore, when a finely divided toner having a volume average particle size of less than 10 μm is used, the resolution is remarkably improved and a clear high quality image in which the difference in shade is faithfully reproduced can be obtained.
However, when the volume average particle diameter of the toner is smaller than 1 μm, adhesion to the carrier due to friction (toner spent) and carrier coverage are increased, so that charging failure and scattering are likely to occur.

For the above reasons, the volume average particle diameter of the toner is preferably 1 to 20 μm, and more preferably 3 to 10 μm. Here, the volume average particle size used as the average particle size is the Coulter Counter TA-II type (Averture 100 μm,
(Made by Coulter). Further, since the toner particles follow the electric field, the absolute value of the charge amount of the toner particles is 1 to
It is desirable that it is larger than 3 μC / g, preferably 3 to 50 μC / g from the viewpoint of securing developability and preventing fogging and scattering. Especially when the particle size of the toner is small, a high charge amount is required.

Examples of such toner include styrene resin, vinyl resin, ethyl resin, rosin-modified resin, acrylic resin, polyamide resin, epoxy resin, polyester resin, and styrene-acrylic resin. A coloring component such as a color pigment in a binder resin such as a polymer resin or a mixed resin, and if necessary, a charge control agent,
A release agent such as wax is added, and the toner can be obtained by a known method such as a pulverization / granulation method, a suspension polymerization method, or an emulsion polymerization method.

To summarize the above, the toner particles preferable in the developing device of the first embodiment use the resin, the charge control agent and the releasing agent as described above, and the coloring component such as carbon and, if necessary, Can be prepared in the same manner as in the known toner particle manufacturing method by adding a charge control agent and the like, and the volume average particle size is 1 to 20 μm, particularly preferably 3 to 10 μm.
m particles.

Next, the developer will be described. In the developing device of the first embodiment, a developer in which the spherical carrier particles and the toner particles as described above are mixed in the same ratio as the conventional two-component developer is preferably used. Above all, when a general coating carrier (density of 5 to 8 g / cm ³ ) is used as a carrier, the toner concentration in the developer is preferably 2 to 30% by weight, particularly 5 to 20% by weight. If the amount is less than 2% by weight, the number of toners required for development cannot be secured, and the coverage ratio is lowered, resulting in excessive charging and deterioration of developability. On the other hand, if it is more than 30% by weight, the coverage becomes large, and charging failure and toner scattering easily occur.

However, when a resin dispersion type carrier having a relatively light density (2 to 4 g / cm ³ ) as described above is used as a carrier in the developer, the toner concentration in the developer is the same as that of a general resin-coated carrier. Slightly higher than when using
It is 40% by weight, preferably 10 to 30% by weight. Next, a second embodiment applied to another developing device will be described with reference to FIG.

FIG. 25 and FIG. 26 are the second embodiment, and are a schematic sectional view and a sectional view of a main part showing a structure of a developing device for a non-magnetic one-component developer. The same parts as the device shown in FIG.
Since the operation is also the same, detailed description will be omitted. The developing sleeve 81 shown in FIG. 25 is a developer carrier made of a non-magnetic material such as aluminum, 85A is a stirring screw that stirs the developer D to make the components uniform, and 85B is the developing sleeve 81 while stirring the developer D. It is a fur brush to supply. Reference numeral 87 denotes a regulation blade, which is preferably an elastic blade type made of elastic rubber such as urethane rubber or silicon rubber in order to charge the toner by rubbing the developing sleeve 81 and the toner together.

If an angle about the rotation center O between the closest position A between the developing sleeve 81 and the photosensitive belt 1 and the downstream end of the control electrode plate 84 is θ ₄ , θ ₄ is −5. It is preferable that ° ≦ θ ₄ ≦ 15 ° (6) as in the first embodiment, but since the control electrode plate 84 is disposed on the upstream side of the developing area A also in this case, 0 ° ≦ θ ₄ ≦ 15 ° It is preferable to set the range of (7).

Therefore, in the second embodiment using the one-component developer D, it is preferable to coat the surface of the developing sleeve 81 with a material similar to the carrier coating material described later, depending on the chargeability of the toner. Also in the second embodiment, a bias voltage is applied to the developing sleeve 81 and the electrode portion 84a as in the apparatus shown in FIG. When the DC voltage applied to the developing sleeve 81 and the DC voltage applied to the electrode portion 84a are equal, the DC bias power source E ₁ can be shared, as shown in FIG.
It is possible to avoid complication of the device.

Here, when a non-magnetic one-component developer is used, the zero peak voltage V _0-P of the AC component applied to the developing sleeve 81 is the same as that of the image forming body 1 and the developer shown in FIG. The closest distance to the developing sleeve 81, which is a carrier, d ₁ (mm), the height of the electrode portion 84a from the developing sleeve d ₂ (mm), the toner volume average particle diameter dt (μm) in the developer, When the average charge amount of the toner is Q ₁ (μC / g), 5Q ₁ dt ・ d ₂ <V _0-P <100Q ₁ dt ・ d ₁ (8) Especially, 10Q ₁ dt ・ d ₂ The range of <V _0-P <80Q ₁ dt · d ₁ (9) is preferable. Here, the average charge amount Q ₁ of the non-magnetic one-component toner is the closest to the developing device 8a having a developing roller having a diameter of 20 mm, which is equipped with the above-mentioned regulating blade 87 having a conductive plate of 2 cm × 5 cm and having a closest distance of 0.7 mm. 180 rpm by supplying the charged one-component developer to the developing roller.
DC and AC superimposed voltage (eg DC voltage 1000V, AC zero peak voltage 750V)
_0-P , AC frequency 8kHz) is applied to develop the toner in the developer on the conductive plate, the conductive plate on which the toner is developed is connected to a Faraday gauge, and the toner is blown off by nitrogen gas. Is a value obtained by measuring the amount of charge and the weight of the toner that is blown off at this time.

Further, d ₂ is the height of the electrode portion 84a from the developing sleeve 81, and (0.2 to 0.6) d ₁ is preferable from the viewpoint of preventing discharge to the developing sleeve and the image forming body and securing developability, and is applied. The frequency of the AC component is 100Hz to 20kHz, especially 1kHz to 10kH
It is preferably z. As the developer, a fluidizing agent such as colloidal silica may be added to the toner and used as it is as the developer D.

The charge amount of the one-component developer is 1 to 1 in absolute value.
30 μc / g, especially 1 to 20 μc / g ensures developability,
It is desirable from the viewpoint of preventing fog and scattering. Also control electrode plate
84 can be commonly used for the developing devices 8 and 8a shown in FIGS. In the color image forming apparatus shown in FIG. 4 equipped with the developing apparatus shown in FIGS. 1 and 25 described above, reversal development was performed using an OPC photosensitive member that is negatively charged as a photosensitive member of the photosensitive belt 1. As the control electrode plate 84 provided in the apparatus used in this experiment, the following one was prepared.

That is, a glass epoxy plate having a thickness of 0.1 mm is used as the insulating support member 83 of the control electrode plate 84, and an electrode portion 84a is formed by an etching method using an electrolytic copper foil having a width of 0.5 mm in the circumferential direction and a thickness of 0.02 mm. To form a position retracted 0.3 mm from the tip,
A control electrode plate was provided with a cover member 83d made of a glass epoxy sheet having the same thickness as the insulating support member 83 and having a thickness of 0.1 mm.

First, the experimental method and the result of the developing device using the two-component developer will be described. An image was formed by the color image forming apparatus shown in FIG. 4 using the developing apparatus shown in FIG. The photoconductor belt 1 is an OPC photoconductor, the peripheral speed is 180 m / sec, the maximum potential of the electrostatic latent image formed on the photoconductor belt 1 is -850V (non-image part potential), the lowest potential is -50V (image part). Potential), the outer diameter of the developing sleeve 81 is 20 mm, the rotating speed of the developing sleeve is 350 rpm, the strength of the magnet in the developing sleeve is 700 gauss, d ₁ = 0.5 mm, d ₂ = 0.25 mm, θ ₁ = 1 °,
θ ₄ = 2 °, the control electrode plate 84 used was the one described above under the conditions shown in Table 1. Note that urethane rubber having a hardness of 50 ° was used as the vibration prevention material.

For the two-component developer, a spherical carrier obtained by coating spherical ferrite particles having a magnetization intensity of 25 emu / g with a methylremethacrylate / styrene copolymer resin as a carrier was used. Volume average particle size is 45 μm and density is 5.
It was 2 g / cm ³ . As the toner, 100 parts by weight of styrene-acrylic resin and 10 parts by weight of each color pigment are melted and kneaded, and then pulverized and classified to obtain yellow, magenta, cyan and black toners having a volume average particle diameter of 8.5 μm. It was Each toner was added with 2 parts by weight of colloidal silica as a fluidizing agent. The density was 1.1 g / cm ³ .

A mixture of the above carrier and toner was used so that the toner was 10% by weight of the whole.
The average charge amount Q ₂ of the toner in the developer is yellow; -21.7 µc / g, magenta; -22.0 µc / g, cyan;
It was -21.9 µc / g, black; -22.3 µc / g. still,
The density was measured using a dry densitometer Acupic 1330 (manufactured by Micromeritics).

Using the color image forming apparatus equipped with the control electrode plate, a comparative experiment was carried out under the image forming conditions of Table 1 to record 50,000 color images. The results are shown in the result column of Table 1.

[0079]

[Table 1]

In the presence of the anti-vibration material, there is no unevenness in conveyance, white lines, image missing, step unevenness, and density excellent in gradation,
And a good image with high resolution was obtained stably,
In the absence of the anti-vibration material, uneven transfer occurred from about 1000 copies, and white streaks, image blanks, and uneven steps occurred on the image.
Next, the experimental method and results of the developing device using the one-component developer will be described.

An image was formed using the developing device shown in FIG. 25 and the color image forming device shown in FIG. The photoconductor belt 1 is an OPC photoconductor, the peripheral speed thereof is 180 m / sec, and the maximum potential of the electrostatic latent image formed on the photoconductor belt 1 is -850V.
(Non-image part potential), minimum potential -50V (image part potential), outer diameter of developing sleeve 81 20 mm, rotation speed of the developing sleeve 180 rp
m, the surface of the developing sleeve is coated with styrene-acrylic resin, and the developer regulating blade 87 is an elastic blade made of urethane rubber. Also, d ₁ = 0.5m
m, d ₂ = 0.25 mm, θ ₄ = 2 °, and the control electrode plate 84 used was the one described above under the conditions shown in Table 2. Note that urethane rubber having a hardness of 50 ° was used as the vibration prevention material.

[0082]

[Table 2]

As a toner for a one-component developer, 100 parts by weight of styrene-acrylic resin, 10 parts by weight of each color pigment, and 2 parts by weight of nigrosine were melted and mixed, and then pulverized and classified to obtain a volume average particle diameter of 8.5 μm. To obtain yellow, magenta, cyan and black toners. The charge amount is yellow; -2.2 μc / g, magenta; -3.1 μc / g, cyan; -2.3
μc / g, black; -2.1 μc / g. Each toner was added with 2 parts by weight of colloidal silica as a fluidizing agent. The density was 1.1 g / cm ³ .

Using the color image forming apparatus equipped with the control electrode plate, a comparative experiment was conducted under the same image forming conditions as shown in Table 2 to record 50,000 color images. The results are shown in the results column of Table 2. With the anti-vibration material, it was possible to obtain a stable image with high density and excellent resolution without unevenness in conveyance, white stripes, image blanking, step unevenness. In the absence of this condition, uneven transport occurred from about 1000 copies, and white streaks, missing images, and uneven streaks occurred on the image.

From the above results, it is possible to improve the image quality by supporting the control electrode plate through the anti-vibration material and to perform stable development. The first and second
In the embodiment described above, the experimental results using the control electrode plates having the shapes shown in FIGS. 5 and 6 were described as an example, but similar results are obtained with the control electrode plates having the shapes shown in FIGS. 7 to 16.

The present invention is not limited to the developing device of the color image forming apparatus, but can be applied to the developing device of the monochrome image forming apparatus.

[0087]

As described above, according to the first aspect of the invention, the control electrode plate is fixed to the developing device via the vibration preventing member, so that the vibration of the control electrode plate during the development is prevented. It can be reduced by the member. As a result, it is possible to reduce the occurrence of image defects such as horizontal stripes, white spots, and stepped unevenness due to vibration, and to stably obtain a high-quality image having high resolution and developability.

According to the second aspect of the invention, the vibration of the control electrode plate can be reduced with a simple structure by using the rubber elastic body for the vibration preventing member. Further, the elastic characteristics of the vibration prevention member can disperse the local pressing force generated at the mounting portion of the control electrode plate. As a result, the control electrode plate can be pressed against the developer transport body with a uniform pressure, and the occurrence of image defects such as vertical stripes and white spots can be further reduced.

According to the third aspect of the invention, the fixing means for sandwiching the end portion of the control electrode plate opposite to the electrode portion in the vibration preventing member and fixing the vibration preventing member so that a force in the sandwiching direction acts. Thus, the vibration preventing member can be securely fixed to the developing device. According to the invention as set forth in claim 4, the vibration prevention member having the end portion of the control electrode plate sandwiched is sandwiched by the two members, and the two members are fastened to each other, whereby the vibration prevention member and the control electrode plate are evenly arranged. It can be fastened by pressing force.

According to the fifth aspect of the present invention, the flat member that contacts one surface of the vibration preventing member in the sandwiching direction and the member that contacts the opposite surface and the back surface of the vibration preventing member are fastened together by the fastening member. The vibration preventing member can be fastened in the same direction as the sandwiching direction of the control electrode plate with a simple structure. Claim 6
According to the invention described in (1), by fastening the leaf spring member that contacts the one side surface and the back surface of the vibration prevention member in the sandwiching direction and the member that contacts the opposite surface of the vibration prevention member in the sandwiching direction, , The repulsive force of the leaf spring member presses against the vibration prevention member,
The vibration prevention member can be more reliably fixed.

According to the invention described in claim 7, the flat plate member that comes into contact with one surface of the vibration prevention member in the sandwiching direction and the member that comes into contact with the opposite surface of the vibration prevention member are fastened together. Thus, the vibration preventing member can be fixed by a simple work by locking it freely. According to the invention as set forth in claim 8, the control electrode plate, the vibration preventing member and the pressing member are collectively pressure-bonded, so that the control electrode plate can be fixed to the vibration preventing member by a simpler operation. Further, the control electrode plate can be more reliably fixed by the urging action of the fastening member.

According to the ninth aspect of the invention, the control electrode plate can be fixed with a simpler structure by adhering the control electrode plate to the developing device via the vibration preventing member. According to the tenth aspect of the present invention, by covering the electrode portion of the control electrode plate so as not to be exposed to the outside, stains on the electrode portion during development can be reduced, and image defects can be further reduced.

According to the eleventh aspect of the present invention, by providing a plate-shaped covering material on the upper surface of the electrode portion of the control electrode plate, the electrode portion can be covered with a simple structure. In addition, it is possible to reduce contamination of the electrode portion during development, and further reduce image defects.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a developing device according to a first embodiment.

FIG. 2 is an enlarged cross-sectional view of the developing device according to the first embodiment.

FIG. 3 is a diagram showing another example of the bias power source of the developing device in the first embodiment.

FIG. 4 is a schematic configuration diagram showing a color image forming apparatus including a developing device in the first embodiment.

FIG. 5 is a perspective view showing an example of a control electrode.

FIG. 6 is an enlarged cross-sectional view showing an example of a control electrode.

FIG. 7 is a diagram showing an example of a method of disposing control electrodes.

FIG. 8 is a diagram showing an example of a method of disposing control electrodes.

FIG. 9 is a diagram showing an example of a method of disposing control electrodes.

FIG. 10 is a diagram showing an example of a method of disposing control electrodes.

FIG. 11 is a diagram showing an example of a method of disposing control electrodes.

FIG. 12 is a diagram showing an example of a method of arranging control electrodes.

FIG. 13 is a diagram showing an example of a method of disposing control electrodes.

FIG. 14 is a diagram showing an example of a method of arranging control electrodes.

FIG. 15 is a diagram showing an example of a method of disposing control electrodes.

FIG. 16 is a diagram showing an example of a method of disposing control electrodes.

FIG. 17 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 18 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 19 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 20 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 21 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 22 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 23 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 24 is a diagram illustrating a method of fixing the control electrode plate.

FIG. 25 is a schematic cross-sectional view of a developing device according to a second embodiment.

FIG. 26 is an enlarged cross-sectional view of the developing device according to the second embodiment.

[Explanation of symbols]

 1 photoconductor belt (image forming body) 6 scorotron charger 7 laser writing device 8 developing device for two-component developer 8a developing device for one-component developer 8A developing device for yellow component 8B developing device for magenta component 8C cyan component Developing device for 8D black component 81 Developing sleeve 82 Magnet 82a Main pole 83 Insulating support member 84 Control electrode plate 84a Electrode part 84c Covering member 84d Covering member 86 Regulation blade 91 Vibration preventive material 94 Locking member 95 Crimping member 96 Pressing member A Development area D Developer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroyuki Nomori Inventor Hiroyuki Nomori 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Co., Ltd.

Claims (11)

[Claims] 1. A voltage-applying electrode part supported by an insulating member in contact with a developer layer is arranged in a developing area of a developer transporting body arranged opposite to an image forming body or in an upstream part of the developing area. A developing device having a control electrode plate provided, wherein the control electrode plate is fixed to the developing device via a vibration preventing member. 2. The developing device according to claim 1, wherein the vibration preventing member is a rubber elastic body. 3. The electrode portion is disposed at one end of the control electrode plate, and an end portion of the control electrode plate opposite to the electrode portion mounting side is sandwiched by a vibration prevention member, and the vibration prevention member is provided. 3. The developing device according to claim 1 or 2, wherein the developing device is fixed to the developing device via a fixing means that fixes it so that a force in the pinching direction acts. 4. The fixing means includes two members for sandwiching the anti-vibration material in the sandwiching direction of the end portion of the control electrode plate, and these two members.
The developing device according to claim 3, further comprising a fastening member that fastens the two members together. 5. The two members are composed of a flat plate member, one of which is in contact with one surface of the vibration prevention member in the sandwiching direction, and the other of which is a member in contact with the opposite surface and the back surface of the vibration prevention member. 5. The developing device according to claim 4, wherein the fastening member fastens the two members to each other in the same direction as the sandwiching direction of the end of the control electrode plate of the vibration prevention member. 6. One of the two members forms an acute angle with which one of the two members can come into contact with the surface on one side of the anti-vibration member in the sandwiching direction and the back surface.
The leaf spring member having a surface and the other member that is in contact with the opposite surface of the vibration prevention member are formed. By fastening the two members together, the two surfaces forming an acute angle of the leaf spring member are expanded. The developing device according to claim 4, wherein the reaction force urges a force in the sandwiching direction. 7. The two members are composed of a flat plate member, one of which is in contact with one surface of the vibration preventing member in the sandwiching direction, and the other of which is a member in contact with the opposite surface of the vibration preventing member. The developing device according to claim 4, wherein the fastening member is formed so as to be detachably locked to the two members. 8. The anti-vibration material is provided on both surfaces of an end portion of the control electrode plate opposite to the electrode portion, and a pressing member is provided on each surface of the anti-vibration material opposite to the surface in contact with the control electrode plate. The control electrode plate, the vibration-preventing member and the pressing member are sandwiched by elastically biased fastening members,
3. The developing device according to claim 1, wherein the control electrode plate, the vibration preventing material, and the fixing member are pressure-bonded to each other, and the fastening member is fixed to the developing device. 9. The developing device according to claim 1, wherein the control electrode plate is fixed to the developing device by adhesion via a vibration preventing member. 10. An electrode part is formed on the upper surface of one end of the control electrode plate, and the outer peripheral part of the electrode part exposed to the outside is covered with an electrode covering member. The developing device according to claim 9. 11. The control electrode plate according to claim 1, wherein an electrode portion is formed on an upper surface of one end portion of the control electrode plate, and a flat plate-shaped electrode covering member is provided on the upper surface of the electrode portion. The developing device according to any one of claims.