JPS63311365A - Corona electrifying device - Google Patents

Abstract

PURPOSE:To obtain a corona electrifying device which is free from the generation of an uneven discharge and the decomposition and deteriorating of an electrifier constituting member, consists of a simple constitution, and also, can be miniaturized, by forming a integrally a shield member and a grid electrode member by an activated carbon fiber material. CONSTITUTION:In a corona electrifying device consisting of a corona discharge electrode 1, a shield member 2 for surrounding the corona discharge electrode, and a grid electrode 4 provided on an opening part 3 of a shield member, the shield member 2 and the grid electrode member 4 are formed integrally by an activated carbon fiber (ACF) material. As for the ACF, its spattering rate is smaller than that of a metals, therefore, it is suppressed that an atom. adheres to the grid/shield members, 2, 4 of the corona electrifying device. In such a way, a uniform and stable discharge characteristic is obtained, an effect of a catalyst action for decomposing the ozone generated at the time of corona discharge is also large, and also, since the grid electrode 4 and the shield member 2 are formed integrally, the constitution is simple and light in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corona charging device used in image forming apparatuses such as electrophotographic copying machines and laser printers.

BACKGROUND ART AND PROBLEMS An example of a conventional electrophotographic copying machine will be described with reference to the schematic diagram of FIG. 3.

The charge receptor 10, which has a photoconductor layer formed on an aluminum substrate, has a drum shape, and its surface is uniformly charged by a charging device 23 before being irradiated with image information. A document table 11 is provided above the document table 11 on which a document 13 to be copied is placed, and below the document table 11 there is a light source 12 that irradiates and covers the document 13, and a charge receptor that directs the reflected light from the document 13. An optical system 14 leading to the optical system 10 is installed.

Further, the electrostatic latent image formed on the surface of the charge receptor 10 by the exposure process is developed into a toner image by a developing device 15 installed around the charge receptor 10, and then transferred to a transfer device 16.
The toner image is transferred onto the paper 18 fed from the paper feeding device 17.

The paper 18 on which the toner image has been transferred is placed in a charging bag for peeling @ 19
The toner image is removed from the charge receptor 10 and sent to the fixing device 20, where the toner image on the paper 181 is fixed onto the paper 18.

On the other hand, untransferred toner remaining on the surface of the charge receptor 10 in contact with the transfer process is neutralized by a pre-cleaning corotron 21 and then removed from the surface of the charge receptor 10 by a cleaning device 22.

In such a conventional electrophotographic copying machine, in order to uniformly charge the photoreceptor (charging device 23), to transfer the toner image (transfer device 16), and to peel off the paper (separation charging device 19), ), a corona charging device is used to remove residual charges (pre-cleaning corotron 21), etc.

Examples of corona charging devices include a corotron, which has a corona electrode made of one or more thin metal wires surrounded by a metal shield plate, a corotron, which has a plurality of needle electrodes lined up instead of the metal wire, or a corotron.・There is something called a scorotron that has multiple parallel line grids on the front of a Ron-type corona charger.

In these corona chargers, the electrodes are exposed to the atmosphere, so toner used for development may adhere to them, and dust from within the copying machine may adhere to them, shortening the life of the electrodes. Causes or covers uneven discharge. In addition, when negative discharge or AC discharge is performed, since the discharge type is similar to glow discharge, atoms in the shield are sputtered out, causing deterioration of the shield and adhesion of shield atoms to the discharge electrode. This is one of the causes of discharge unevenness.Also, there is a drawback that the shield is oxidized by substances g'-1 such as ozone, nitrogen peroxide, NOx, etc. generated by corona discharge, resulting in discharge mucus.

As shown in FIG. 4, the present applicant has developed a corona charging device that overcomes these drawbacks by making at least the inner surface of the shield 6 made of activated carbon fiber.
r: Hereinafter abbreviated as ACF. ) 7, electrode wire 1
By decomposing 039 generated in the surface corona plasma region 8 in the ACF 7, the amount of 03 released from the corona charger, which is the source of O3, is reduced, and the generation of NOx is also reduced. 5i02 growing on the surface of 1
We have proposed a corona charger that slows down the deterioration of the electrode wire 1 and extends its operating life by adsorbing 3i gas (silicone oil vapor, etc.), which causes discharge products consisting of No. 1983-40396).

However, in recent years, organic photoreceptors (
OPC> etc. are often adopted in copiers, printers, etc., and often produce negative discharge, but negative discharge has more uneven discharge than positive discharge, and as a countermeasure to this, the scorotron method described above is used. .

In this case, a bias voltage is applied to the grid to control the potential of the object to be charged. Conventionally, a plurality of metal wires of about φ0.1 #W are stretched in parallel as grid electrodes, or
It has a very complex structure, such as etching a thin metal plate to form grid-like openings and tensioning them with springs in the longitudinal direction, resulting in a large number of parts and high costs. There was a drawback. Furthermore, the aforementioned grid electrode also has the disadvantage that it is oxidized by ozone generated by corona discharge and its quality deteriorates.

Therefore, it is an object of the present invention to eliminate the above-mentioned drawbacks of a corona charging device, and to prevent uneven discharge and deterioration of charger constituent members, and to provide a scorotron type corona charging device that is simple in construction and capable of being miniaturized. Our goal is to provide the following.

Means to Solve the Same Problem As shown in FIG. 1 in a perspective view and FIG. 2 in a side sectional view before assembly, the present invention comprises a corona discharge electrode 1, a shield member 2 surrounding the corona discharge electrode, and a shield member. In a corona charging device consisting of a grid electrode 4 provided in an opening 3 of
This corona charging device is characterized in that the shield member 2 and the grid electrode member 4 are integrally molded from an activated carbon fiber (ACF) material 11.

The 8CF used in the corona charging device of the present invention can be prepared by any conventionally known method. A can be built. For example, after oxidizing polyacrylonitrile fibers, or pre-oxidizing and carbonizing Cell Lithium fibers, pitch fibers, and phenolic resin fibers, the concentration of polyacrylonitrile fibers is 5Vo1% or more,
Preferably, it is produced by activating for 1 minute to 3 hours in a high temperature atmosphere of 350° C. or higher using an activating gas of 80 Vo 1% or higher (for example, water vapor, carbon dioxide, ammonia gas, or a mixture thereof).

However, the production of ACF is not limited to the above method.

The ACF used in the present invention has an adsorption surface area of 300 to 20
00TIt/9. Such ACF has an equilibrium adsorption maximum of about 1.5 to several times as much as granular activated carbon, and an adsorption rate of 10 to 100 times.

Such activated carbon fibers are electrically conductive and can be produced at low cost, and unlike baked crystals of powdered activated carbon, there is almost no dusting due to desorption of activated carbon, and by utilizing the characteristics of fibers, It can be easily processed into felt, paper, honeycomb, cloth, and coated shapes (adjusted by coating with pine goo mixed with fibers).

Therefore, by using the ACF material, the shield member and the grid electrode can be easily integrally molded,
Further, a bias voltage can be directly applied to control the potential of the charged object.

In the present invention, ACF can be used as (+) alone, or it can be used as a material in which ACF is supported with a substance having catalytic activity such as (ii) a metal, (iii) a metal acid compound, or (iv) a metal chelate compound. Also preferably used are corona charging devices constructed from these preferred materials, which are also objects of the present invention.

Examples of metals that are adhered and supported on 80F include Ti,
V, Cr, Mn, Fe, Co, Ni.

cu17r, Nb, MOlRulRh, Pd.

Examples include one type of P, Aq, Sn, W, Pb, or an alloy thereof.

Further, as the metal oxide, for example, one of the above metal oxides is used.
A species or two or more species may be mentioned.

Among these, ACF materials carrying manganese oxide are particularly preferred.

The corona charging device shown in FIGS. 1 and 2 has the simplest configuration in which the grid electrode and the shield member are integrally molded. Corotron wire (corona discharge electrode) 1 has a wire diameter of 1
It is a tungsten wire with a thickness of about 0 to 100 μm, and is installed under a specific tension via springs or the like to insulating blocks at both end portions (not shown).

The thickness of the ACF material can be arbitrarily set to about 0.1 to 2M, but in order to form the opening 3 of the grid part,
In order to maintain the shape of the grid shield, the thickness is desirably 0.3al111 or more.

According to the studies of the present inventors, ACF is a paper-like ACF that is obtained by pulverizing 80F and mixing it with cellulose fibers, then making paper using a normal wet papermaking method, and firing the paper.
A thickness of 0.3 to 1.5 m) was most suitable for integral molding. Further, it has been found that if the aperture ratio of the openings 3 is 70% or more, there is no problem in controlling the charging property.

Since the grid electrode and shield member integrally molded article 2 is paper-like, it is very light and easy to handle.

In addition, it has sufficient strength and can be easily attached to the machine body 5 by inserting it along the groove in the axial direction, or by opening the open part A to the right and snap-fitting it to the machine body 4. Can be done.

Effects of the Invention Since the ACF used in the scorotron type corona charging device of the present invention has a lower sputtering rate than metal, adhesion of atoms to the grid shield member of the corona charging device is suppressed, and uniform and stable discharge characteristics are achieved. can get. In addition, the catalytic effect of decomposing ozone generated during corona discharge is highly effective, contributing to low ozone production in copiers, printers, etc.

In addition, since the grid electrode and shield member are integrated, the configuration is extremely simple, and the corona charger has a low system I.
It is possible to reduce the size and weight.

Furthermore, ACF has many advantages such as no problem of environmental pollution, and is also effective in downsizing the entire device using the corona charging device of the present invention.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the corona charging device of the present invention, Fig. 2 is a side sectional view of the corona charging device before installation in the main body of the machine, Fig. 3 is a schematic diagram of an example of an electrophotographic copying machine, and Fig. 4 is FIG. 2 is a side sectional view of an example of a conventional corona charging device using ACF. Symbols in the figure: 1...Discharge wire; 2...Amount of grid electrode/shield member integrally molded; 3...1 opening; 4...Grid electrode; 5...Lower part of the machine body): 6...
Metal shield; 7...Activated carbon fiber (ACF):
8... Corona plasma area; 9... A-sin; 1
0...Charge receptor; 11...Original table; 12...
・Light source; 13... Original; 14... Optical system; 15
Developing device; 16 Transfer device; 17 Paper feeding device; 18 Paper; 19 Charging device for peeling;
20... Fixing device; 21... Pre-cleaning corotron; 22... Cleaning device; 23... Charging device. Figure 1 Figure 2

Claims (1)

[Claims] 1) A corona charging device comprising a corona discharge electrode, a shield member surrounding the corona discharge electrode, and a grid electrode provided in an opening of the shield member, wherein the shield member and the grid electrode member are A corona charging device characterized by being integrally molded from activated carbon fiber material. 2) The corona charging device according to claim 1, wherein the activated carbon fiber material carries a metal. 3) The corona charging device according to claim 1, wherein the activated carbon fiber material supports a metal oxide. 4) The corona charging device according to claim 3, wherein the metal oxide is manganese oxide. 5) The corona charging device according to claim 1, wherein the activated carbon fiber material supports a metal chelate compound.