JP2570594B2 - Electric field curtain generator for transporting developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric field curtain generator for conveying a developer to a photosensitive drum or the like by means of an electric field curtain, and more particularly to a device for conveying a developer stably and without scattering. The present invention relates to an electric field curtain generator for transporting a developer.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of an essential part showing an example of a conventional electric field curtain generator for transporting a developer, and FIG. 4 is a schematic structural view showing a developing apparatus using the conventional electric field curtain generator. It is. Hereinafter, description will be made based on these drawings.

[0003] The electric field curtain generator 50 comprises electrodes 52a, 52b, 52c,.
4 and has a flat plate shape as a whole. The electric wires 58 of each phase of the three-phase AC power supply 56 are connected to the electrodes 52a, 52b, 52c. The electric field curtain generating device 50 is installed in a developer storage container 60 and transfers a developer 62 such as a toner to an electrostatic latent image holder 6 such as a photosensitive drum.
4.

Next, the operation of the electric field curtain generator 50 will be described.

[0005] The developer 62 is charged in advance by any method. Here, when a three-phase AC voltage is applied from the three-phase AC power source 56 to the electrodes 52a, 52b, 52c,..., A traveling wave of the electric field curtain having the direction of the arrow 66 is generated.
The developer 62 receives an attractive force and a repulsive force from the electrodes 52a, 52b, 52c,... And vibrates in an arc shape in a floating state, and the electrostatic latent image holder 64 from the lower portion of the developer storage container 60.
Transported to Then, a part of the developer 62 jumps to the electrostatic latent image holder 64 corresponding to the electrostatic latent image. The remaining developer 62 climbs on the electric field curtain generator 50,
As shown by an arrow 68, the developer drops to the lower part of the developer storage container 60.

The force exerted on the developer 62 by the electric field curtain generator 50 is a combined force of a suction force and a repulsion force by the electrodes 52a, a centrifugal force due to the arc-shaped vibration of the developer 62, and the like. This resultant force is a force repelling the electric field curtain generator 50. Therefore, the electric field curtain generator 5
Reference numeral 0 indicates that the developer 62 is floated by repelling the developer 62 upward due to the resultant force when the developer 62 falls by its own weight into the electric field curtain generator 50.

[0007] Such an electric field curtain generating device 50 includes:
For example, it is described in JP-A-63-13067.

[0008]

However, the conventional electric field curtain generator 50 has the following problems.

The electric field curtain generator 50 merely floats the developer 62 above it. Therefore, the structure is limited to a flat plate or the like, and the installation position is also limited below the electrostatic latent image holder 64. This point
This reduces the degree of freedom in designing the device, and hinders miniaturization of the device.

It is impossible to forcibly attract the developer 62 that has soared upward due to a collision or the like. In addition, since the only method of collecting the developer 62 that has climbed on the electric field curtain generating device 50 is to drop naturally, the developer 62 always scatters in the developer storage container 60. Therefore, the developer 62 on the electric field curtain generating device 50 is distributed to the upper part. The developer 62 distributed above this adheres to a portion other than the electrostatic latent image of the electrostatic latent image holding member 64, causing a deterioration in image quality.

[0011]

An electric field curtain generating apparatus according to the present invention has been made to solve the above-mentioned problems, and has an electrode layer including an electrode for generating an electric field curtain;
It is composed of a laminate with an electret layer charged to the polarity to attract the developer.

The laminate may be cylindrical, and the electret layer may be on the side in contact with the developer.

[0013]

The electrode layer generates an electric field curtain to give a repulsive force to the developer, thereby causing the developer to float. The electret layer attracts developer that is too far away from the electric field curtain generator. Since the electrode layer and the electret layer are stacked, the developer is conveyed to the electrostatic latent image holding member without being too far from the electric field curtain generator.

When the laminate is formed in a cylindrical shape, the developer is recovered by transporting the developer along the circumference.

If the electret layer is on the side in contact with the developer, the electret layer needs to be charged less.

[0016]

FIG. 1 is a sectional view of an essential part showing an embodiment of an electric field curtain generator according to the present invention, and FIG. 2 is a schematic structural view showing a developing device using the electric field curtain generator. Hereinafter, description will be made based on these drawings.

The electric field curtain generator according to the present invention is a laminate of an electrode layer 12 including electrodes 10a, 10b, 10c,... For generating an electric field curtain, and an electret layer 14 charged to a polarity for attracting a developer 62. 16.

The laminated body 16 is arranged so as to face the electrostatic latent image holding body 64, and has a cylindrical shape, more specifically, a horseshoe shape opened to the developer storage container 20 side. The electret layer 16
It is on the outer peripheral side of the laminate 16, that is, on the side in contact with the developer 62. On the inner peripheral side of the laminate 16, an insulating member 22 and a reinforcing base material 24 are sequentially laminated. The reinforcing substrate 22 is formed of metal or resin.

The insulating member 22 is connected to the electrodes 10a... In response to the output voltage of the three-phase AC power supply 56 applied to the electrodes 10a.
It is provided for insulation between them and insulation with the reinforcing base material 24. The electrodes 10a are formed by disposing long wires or thin plates in the direction perpendicular to the drawing, that is, in the axial direction of the electrostatic latent image holder 64, at regular intervals in the circumferential direction of the electrode layer 12 with an insulating material interposed therebetween. As a set, the electric wires 58 of each phase of the three-phase AC power supply 56 are sequentially wired and connected.

The electret layer 14 has a thickness of 50 to 500 μm.
This is an electretized film having a uniform thickness D of m. That is, it is a film in which a charge is given by an electrode to which a high voltage is applied while a mechanical or thermal treatment or the like is applied to a resin film such as polyethylene terephthalate, and the charge is permanently retained. The electret layer 14 is laminated so as to be in close contact with the electrode layer 12.

The laminate 16 and the like thus constructed are placed in the developer storage container 20 with a gap of 20 to 2000 μm from the electrostatic latent image holder 64 to form the developing section 26. . Around the stacked body 16, a developer thickness regulating plate 32 is provided on the upstream side in the moving direction of the developer 62 (arrows 28 and 30), and the developer 62 is stored in the developer storage container 20 on the downstream side. A recovery sheet 34 that collects and prevents the developer 62 from leaking from the developer storage container 20 is provided.

The developer thickness regulating plate 32 is made of a metal member, and is supplied with an output voltage from ground or another power source (not shown).
A stirring paddle 36 for stirring the developer 62 is rotatably mounted in the developer storage container 20.

The electrostatic latent image holding member 64 is composed of, for example, a photoreceptor, a dielectric drum, or a belt having a Se-based metal layer or an OPC layer, and rotates in the direction of arrow 38. Here, the description will be made assuming that the negative polarity OPC is used. Developer 62
Is a non-magnetic one-component developer having a diameter of 5 to 15 [mu] m and containing a styrene-acrylic or polyester resin as a main component. Here, the negative electrode is charged.

Next, the operation of the electric field curtain generator and the developing device thus configured will be described.

When the image forming operation is started, an output voltage from the three-phase AC power supply 56 is applied to the electrodes 10a. Also,
The stirring paddle 36 starts rotating, and the developer 62 in the developer storage container 20 is conveyed to the laminate 16 side. Then, the developer 62 is transported on the laminate 16 toward the developer thickness regulating plate 32 by the electric field curtain. At this time, the developer 62
As the developer is transported, the developer 62 is charged and charged.

The presence of the electret layer 14 on the electrode layer 12 allows the developer 62 to be transported without the developer 62 falling off or separating from the laminate 16. In this way, the developer 62 is conveyed to the developing unit 26 while being charged one after another.

The developer 62 conveyed to the developing section 26 faces, via a gap, an electrostatic latent image holding member 64 (an OPC photosensitive member) holding an electrostatic latent image on the surface. Then, due to the electric field formed by the electrostatic latent image and the voltage difference between the output voltage of the three-phase AC power supply 56, the charged developer 62 migrates and adheres to the photoreceptor surface where the charge has been reduced and develops. Form an image. The photoreceptor having the developed image formed on its surface proceeds to a transfer section (not shown), is transferred to a recording medium, and is then fixed and output.

On the other hand, the developer 62 remaining on the laminate 16
Is also the transport force by the electric field curtain and the laminate 1
6 is constrained by the electret layer 14 formed on the surface, and is conveyed in the direction of the recovery sheet 34 on the laminate 16. Then, the developer is again guided to the developer storage container 20, and is again subjected to development. By performing the above repetition, the operation of the developing device proceeds.

In the above description, the developer 62
Is -charged, but is not particularly limited thereto, and may be + charged. A full-color developer can be used as the developer 62.

Although the electrostatic latent image holding member 64 is a negatively charged OPC, the present invention is not limited to this, and any member may be used as long as it can hold an electrostatic latent image as described above.

Although the example in which the stirring paddle 36 is used has been described, another electric field curtain generating means may be provided in the developer storage container 20 to transport and agitate the developer 62. The stirring paddle 36 and another electric field curtain generating means may be combined.

The shape of the laminate 16 may be an elliptical cylinder, a flat plate, or the like.

The moving direction of the developer 62 on the laminate 16 is as follows.
Since the developer 62 does not drop due to the electret layer 14, the developer 62 can be moved in a direction opposite to that in FIG.
In this case, the positions of the recovery sheet 34 and the developer thickness regulating plate 32 in FIG. 2 are reversed, and the shape of the developer thickness regulating plate needs to be different to prevent the developer 62 from leaking. .

A three-phase AC power source 56 for generating an electric field curtain
Is not limited to a sine wave but may be a triangular wave, a rectangular wave, or a combination thereof.

[0035]

According to the electric field curtain generator according to the present invention, while an electric field curtain is generated in the electrode layer to float the developer, the developer which is too far away is attracted by the electret layer, so that the electrostatic latent image is formed. By transporting the developer to the holder, the following effects can be obtained.

Since the falling of the developer can be suppressed, it can be formed into any shape such as a cylindrical shape. Therefore, the degree of freedom of the device configuration is increased, and downsizing of the device can be achieved.

Since the falling and scattering of the developer can be suppressed, it is possible to prevent the developer from adhering to portions other than the electrostatic latent image. Therefore, the image quality can be improved.

When the laminated body is formed in a cylindrical shape, the developer is conveyed along the circumference thereof, so that the developer can be collected without falling, and the scattering of the developer can be prevented.

When the electret layer is on the side in contact with the developer, the amount of electret layer charged can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a developing device using the electric field curtain generating device of FIG.

FIG. 3 is a sectional view of a main part showing a conventional example.

FIG. 4 is a schematic configuration diagram illustrating a developing device using the electric field curtain generating device of FIG. 3;

[Description of Signs] 10a, 10b, 10c, 10d, 10e, 10f Electrode 12 Electrode layer 14 Electret layer 16 Laminated body 62 Developer

Claims (3)

(57) [Claims] 1. An electric field curtain generator for transporting a developer, comprising: a laminate of an electrode layer including an electrode for generating an electric field curtain and an electret layer charged to a polarity to attract the developer. 2. An apparatus according to claim 1, wherein said laminate has a cylindrical shape. 3. The laminate according to claim 1, wherein the electret layer is on a side in contact with the developer.
An electric field curtain generator for conveying a developer according to the above.