JPS63271279A - Screen for carrying fine particles - Google Patents

Abstract

PURPOSE:To obtain a member appropriate for carrying fine particles by the attractive force of electrons charged on the surface of a screen by sticking metal oxide to the surface of the screen consisting of a conductor to adjust the surface resistance of the screen. CONSTITUTION:In an electronic printer or other equipments utilizing toner 3, metal oxide is stuck to the surface of a thin plate such as the screen 9 consisting of a conductor to adjust its surface resistance. The screen 9 to be used for carrying fine particles such as toner with uniform thickness is usually constituted of a conductor, and if the surface resistance is too small, electrified charge is leaked. When the surface resistance is too large, sufficient charge can not be supplied from a power supply to the surface of the screen 9 and the toner can not be stuck to the surface of the screen 9. Consequently, the member is appropriate for carrying fine particles with uniform thickness in addition to application to a toner carrying device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a screen used to convey particulate matter in an electronic printing machine or other equipment using toner.

Taking an electrophotographic copying machine that uses toner as an example of a device for transporting fine particles, FIG. 2 is provided, toner 3 is stored in the hollow roll, and the fiber hair is charged by friction between the fiber hair body 5 implanted on the surface of the hollow roll and the frictional charging member 6 interposed around the fiber hair body 5. The body 5 is charged with an electric charge, the toner 3 flowing out from the through hole 2 is transferred to the charged fiber body 5, and this is transferred to the surface of the screen 9 which is charged by another power source, and the surface of the screen 9 is transferred to the charged fiber body 5. In a developing device of an electrophotographic copying machine having a structure in which toner attached to the fiber body 5 is transferred to an electronic latent image previously formed on the surface of the photoreceptor 11, the toner attached to the fiber body 5 and the screen 9 are transferred. By applying an appropriate potential difference between the photoreceptor 11 and the screen 9, the toner is transferred to the surface of the screen 9 by the potential difference between the photoreceptor 11 and the screen 9. Polar means that it adheres to the surface of the screen 9 where there is a potential difference, and is further transported to an electrostatic latent image on the surface of the photoreceptor 11 where there is a potential difference from the screen 9.

Moreover, in FIG. 2, instead of storing the toner 3 in the hollow roll as described above, the toner 3 is stored in a hopper 14, and the toner is sprinkled onto the surface of the fiber bristle body 5 by a toner roll 15. The rest of the structure is the same as that shown in FIG. 1, and in this case, the rescreen 9 plays an important role in conveying the toner to a uniform thickness onto the photoreceptor.

FIG. 3 shows another embodiment of an electrophotographic copying machine, in which a screen 9 is arranged around a hollow roll 1 in which fibers are implanted. The principle of transporting the toner is the same, in which a voltage with a potential difference from the charge charged on the toner 3 is applied to the screen 9 rotating in the direction of the arrow in the figure, and the photoreceptor 1
The toner 3 is conveyed to the fibrous body 5 and further to the screen 9 and the photoreceptor 11 by applying a voltage having an appropriate potential difference with the screen 9 to the toner 1 in advance.

In each of the above figures, 12 is a bias power source for adjusting the potential difference between the screen 9 and the photoreceptor 11, which is charged by the electrode 10, and 13 is a bias power source for adjusting the potential difference. A regulated power supply, the electrode 1
It is charged by 4.

In order to transport fine particles such as toner with a uniform thickness, a screen is often used.

By the way, the screen is usually made of a conductor, and as it is, the surface resistance is very low. However, if the surface resistance is too low, the charged charges will leak and it will not be possible to provide enough electrons to the surface of the screen. If the surface resistance is too high, the power supply will not be able to supply enough charge to the screen surface, making it impossible to deposit toner on the screen surface.

Of course, this surface resistance value must be adjusted depending on the mass of the toner, the insulation properties and chargeability of the toner, the size of the toner particles, etc., but in any case, it is necessary to Some kind of processing would have to be done to give it some resistance.

(Means and effects for solving the problem) The present invention has been made to solve the above problems, and the surface resistance is adjusted by attaching metal oxide to the surface of the screen made of a conductor. By doing so, it is an object of the present invention to provide a member suitable for transporting fine particles by the attraction of electrons charged on the surface of the screen as described above.

(Example) The present invention will be explained in detail below according to examples.

Although the screen is not shown, in the example, when toner having an average particle diameter of about 20 microns is used, an iron mesh of the mesh screen is used, and the mesh interval of the iron mesh is set to the diameter of the toner. A mesh having a diameter of 30 microns, which is slightly larger than the certain 20 microns, will be described below, and will be described using a mesh made by oxidizing the mesh to form iron oxide.

In what the inventor carried out, the iron mesh formed in the mesh gap of the previous example was heated in an oxygen atmosphere for an appropriate period of time, and when the surface resistance reached the above value, it was taken out. By doing so, the value of surface resistance can be adjusted freely.

However, the structure of the screen and the type of metal oxide are not necessarily limited to these. For example, a thin metal plate with many holes drilled and coated with not only ferric oxide but other metal oxides may also be used. Needless to say, it is good as long as it is electrically conductive.

Also, the method of attaching the metal oxide to the surface of the mesh is not limited to the above, but it is possible to adjust the thickness of the metal oxide coating using plating or other appropriate means so that the resistance becomes appropriate. good.

The screen used in the above example had a surface resistance of 1
Good results were obtained using 30 kilohms/cm2.

The reason for using metal oxides as a means for adjusting the resistance on the surface of the screen is that metal oxides are cheap and easily available, and they can be easily produced by oxidizing the surface of the metal screen as is, as shown in the example above. This is because it is easy to adjust the thickness attached to the surface of the screen, and it is resistant to corrosion.

Examples of thin plates such as screens are not limited to the meshes described above, but metal foils, synthetic resin sheets, or those with a large number of small holes formed therein can also be used.

(Effects of the Invention) As described above, the present invention adjusts the surface electrical resistance of the screen by attaching a metal oxide to the surface of the screen made of a conductor. The material used can be freely controlled and the thickness of the material deposited on the surface can be freely controlled, making it possible to inexpensively manufacture a screen with an appropriate surface resistance suited to the mass of the toner, the diameter of the toner particles, the chargeability of the toner, etc. Moreover, since it is resistant to corrosion, it provides a screen with a long life.

Therefore, the use of the screen of the present invention is not limited to the toner conveying device in an electronic printing machine as in the embodiment described above, but is very suitable for conveying fine particles with a uniform thickness.

[Brief explanation of the drawing]

FIG. 1 is a conceptual side view showing how the present invention is applied to a developing device of an electrophotographic printing machine. Figure 2 is also a drawing similar to Figure 1, but with a slightly different structure of the electronic printing machine. FIG. 3 is a conceptual side view showing an example in which the position of the thin plate such as the screen of the present invention is changed from that in FIGS. 1 and 2. FIG. In the figure, 1...Hollow roll, 3...Toner, 5...Fiber hair, 9...Screen, 11...Photoreceptor .

Claims (1)

[Claims] A screen for transporting particulate matter that has a metal oxide attached to the surface of a thin plate such as a screen made of a conductor to adjust the surface resistance.