JPH07114250A - Wire material for electrode of corona discharge and its production - Google Patents

Abstract

PURPOSE:To provide an electrode wire material for corona discharge having high surface accuracy, improved strength against peeling, and a long life used for an electrophotographic copying machine, and to provide the production method. CONSTITUTION:The electrode wire material for corona discharge consists of a metal core wire and a surface layer comprising at least one of Au, Pt, Ru, Rh, Pd, Os and Ag covering the core wire. The surface layer has at most 0.9mum Rmax surface roughness. The wire is produced by a coating method by forming the surface layer selected from Au, Pt, Ru, Rh, Pd, Os and Ag on the metal wire core and drawing the wire through a drawing die with at least 1% reduction rate of the cross section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire for a corona discharge electrode used in an electrophotographic copying machine (copier), an image forming apparatus, a dust collector, etc., and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, W has been used as an electrode material for corona discharge.
Or for high melting point metal wire such as Mo, Au, Pt, Ru, R
It is well known that a wire coated with a noble metal such as h, Pd, Os, Ir, Ag, or a platinum group element is effective. Generally, the manufacturing method of this type of covered wire is classified into the following two types.

One is a method called a clad method in which a wire is thinned by using the above-mentioned noble metal or a metal pipe of a platinum group element as a raw material and using a W or Mo wire rod as a core wire and performing a process such as wire drawing. There are (JP-A-59-204058, JP-A-61-219414, and JP-A-61-161).
219415). Another method is to form a surface layer made of fine particles on a wire material such as a refractory metal by plating, chemical vapor deposition (CVD), physical vapor deposition (PVD), etc. (hereinafter, these are referred to as coating methods,
JP-A-64-42666 and JP-A-58-8878.
No. 7, publication).

The latter coating method has a predetermined wire diameter (for corona discharge electrodes, the diameter is generally 50 mm).
Coating is performed on the W or Mo wire of about 100 μm) by the above method.

[0005]

However, no matter how the noble metal or platinum group element is coated, the fine particles of the coated metal are all on the surface of the W or Mo wire which is the core wire regardless of the method described above. Is applied to the coating metal, and through a process called a seizure process in the manufacturing process, heat treatment is performed at a temperature near the softening temperature of the coating metal,
It is generally practiced to increase the adhesion strength to W and Mo wires. Therefore, as the heat treatment temperature rises, the higher the heat treatment temperature, the more the metal fine particles undergo solid phase diffusion,
The adhesion strength between the particles and between the metal particles and the W and Mo rays increases. However, when the melting point of the coating metal is reached, the coated metal itself melts and flows out from the surface of the core W or Mo, and a uniform coating layer cannot be obtained. In order to prevent this non-uniform coating formation, heat treatment near the softening temperature of the coating metal is unavoidable.

FIG. 6 shows a wire for an electrode for corona discharge (hereinafter referred to as a charging wire) by a conventional heat-treated coating method.
3 is an electron micrograph showing the metal structure of the above. As shown in Fig. 6, the morphology of the coated metal particles remains on the W or Mo line even after this heat treatment. You can see it. On the other hand, without heat treatment,
The strength of the coated wire is much lower than that of the clad wire. As described above, the charged wire by the coating method is cheaper than the clad method, but (the amount of coating metal used is small. Generally, the coating method uses 0.1 to 3 μm.
m, and the cladding has a coating of 3 μm or more. The reason is that the coating is expensive because it takes a long time to increase the coating amount, while the clad method reduces the coating amount by tearing the substrate during machining such as drawing. This is because it is difficult to form a thin layer because the W and Mo lines of are exposed. ), It is easy to peel off, and there are irregularities of fine particles, and there is a problem that performance as a charging line, that is, (a) corona discharge characteristics and (b) decrease in adhesion strength of the coating film occurs.

On the other hand, it is important to improve the surface roughness of the charging line used in the electrophotographic copying machine in order to improve its performance. The reason for this is that if the surface is rough, that is, a line with irregularities, corona discharge is non-uniformly generated, and when copying is performed, an unclear object, and eventually white stripes or black stripes are generated. At the same time, due to the evaporation of the silicone oil used for fixing the copy, etc., SiO ₂ adheres to the charging line,
In order to cause the same performance deterioration as described above, the recovery of performance is measured manually or automatically after a certain period of use, by removing the deposits on the charging wire. At this time, alcohol or the like is attached to cotton felt or the like to remove it, but if the adhesion strength of the coating film is low, the coating metal peels off and uniform corona discharge characteristics cannot be obtained.

Therefore, a technical object of the present invention is to provide a wire rod for corona discharge electrodes, which has high surface accuracy, improved peeling strength, and has a long life even for an electrophotographic copying machine, and a manufacturing method thereof. is there.

[0009]

The inventors of the present invention improve the surface roughness of the wire by performing cold oil wire drawing in the surface accuracy improvement test of the tube wire and the dot printer wire. It was found that by applying this method to a fine particle coating material, it is possible to measure a significant increase in accuracy, and it was possible to measure the life extension of the electrode material for corona discharge, and the present invention was accomplished. It is a thing.

According to the present invention, it has a core wire portion made of metal and a surface layer covering the core wire portion, and the surface layer is made of Au, P or P.
A wire for a corona discharge electrode comprising at least one selected from t, Ru, Rh, Pd, Os and Ag and having a surface roughness of R _max of at least 0.9 μm is obtained. Here, in the present invention,
As the core wire portion, W and Mo which are refractory metals, alloys containing at least one of them, stainless steel wire,
A Co type amorphous alloy containing Cr can be exemplified, but it is particularly preferable to be one of W, Mo and an alloy containing at least one of these.

According to the present invention, the core wire made of refractory metal is coated with Au, Pt, Ru, Rh, P by a coating method.
A wire rod for corona discharge electrode, characterized in that a surface layer made of at least one element selected from d, Os, and Ag is formed, and a wire drawing process is performed through a wire drawing die at a cross-section reduction rate of at least 1%. A manufacturing method is obtained.

According to the present invention, in the method of manufacturing the wire for corona discharge electrode, the coating method is at least one method selected from a plating method, a CVD method and a PVD method. A method of manufacturing a wire rod for a corona discharge electrode is obtained.

That is, the manufacturing method of the present invention provides an improved material relating to the fine particle coating method by plating, CVD, PVD, etc. (hereinafter referred to as a coating method). Here, in the present invention, as the core portion, W and Mo which are refractory metals and alloys containing at least one of these, stainless steel wires, and Co-based amorphous alloys containing Cr can be exemplified.
It is preferably any one of W, Mo and an alloy containing at least one of these.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an electron micrograph showing the metal structure of a wire (charging wire) for a corona discharge electrode according to an embodiment of the present invention. As shown in this photograph, it can be seen that the surface roughness of the charged wire is improved, and thus the adhesion strength of the metal film forming the surface layer is improved.

The charged wire according to the embodiment of the present invention is a coated wire of noble metal or platinum group element formed by a coating method, using a general drawing machine, and the lubricant is a general one such as oil. By using a diamond die and drawing the coated wire, the surface roughness is improved. As a method of drawing,
The surface roughness of the coated wire is JIS B060.
_Rmax was checked by 1 and a cross-section reduction rate equal to or higher than the roughness was given, and the wire was drawn with a diamond die for wire drawing.

Next, FIGS. 2 to 4 are explanatory views of the apparatus used for measuring the characteristics of the charged wire, FIG. 2 is a perspective view showing the charged wire shield case, and FIG. 3 is a cross-sectional view showing the schematic structure of the forced silicon adhering apparatus. FIG. 4 and FIG. 4 are views showing a voltage distribution measuring device for charging lines. In FIG. 2, the band line shield case 2 is A
The end fixing members 2a and 2b for fixing both ends of the W wire rod 1 as a charging wire to be measured and a U-shaped plate 2c sandwiching the end fixing members 2a and 2b at both ends are provided. ing.

In FIG. 3, the charged wire shield case 2 is shown.
Is housed in the forced silicon adhesion container 3 and the lead wire 4
Is pulled out of the container 3 and grounded via the ammeter 5. On the other hand, to the W wire 1, a voltage of +7.5 kV is applied from a high voltage supply device outside the forced silicon adhesion container 3. The upper part of the forced silicon adhesion container 3 is connected to the silicon vapor generation container 7 via a communication pipe 7a. Inside the silicon vapor generation container 7, a silicone oil container 8 containing silicone oil and the silicone oil container 8 are provided. A heater 9 for heating the container 8 is provided. An exhaust fan 10 is provided at the bottom of the forced silicon adhesion container 3 to exhaust the inside of the container.
The lead wire 6a and the lead wire 4 are filled with an insulating material (not shown) between the walls of the container 3 to completely seal the inside of the container 3.

In FIG. 4, the charging shield case 2 is
It is grounded via a conductor 12.

A stainless steel plate 13 is provided so as to face the W wire 1 of the charging shield case 2, and a sensor 13 is movably provided on the stainless steel plate 13. This sensor 14 is connected to a voltage recorder 15 and its voltage is detected. The W wire 1 is connected to the high voltage supply device 16, and one end is grounded via the lead wire 17.

Hereinafter, the examples of the present invention will be described in detail with reference to specific examples of production.

(Example 1) An Au-plated W wire having a film thickness of 0.5 μm formed by wet plating and an Au-plated W wire having a film thickness of 1.5 μm formed by wet plating, each having an outer diameter of 60 μm. Prepare the wire of, and general W
Using a wire drawing machine, commercially available cold wire drawing oil was used as a lubricant, and the wire was drawn with a diamond die.

The surface roughness of these two types of wire and the surface roughness of the drawn wire are shown in Table 1 below. The surface roughness of the element wire is 0.5 μm Au-plated W wire and the film thickness is 1.5 μm.
Since it is different from the mAu-plated W wire, 1-3 kinds of diamond dies with different dies diameter are prepared.
Tests with different cross-section reduction rates were also conducted. The surface roughness R _max
Was measured according to JIS B 0601, and an average value was obtained by measuring 10 points on the same line. The measurement method is
Using a commercially available surface roughness meter, measurement was performed by running a measuring terminal (pickup) in the longitudinal direction of the wire. Measurement conditions are speed, 0.3 mm / sec, vertical magnification 2,000 times, horizontal magnification 20
A portion having a total length of 2.5 mm was measured by doubling. The Au plating amount is shown by calculating the average Au adhesion amount by the weight method using a wire 10 m having an outer diameter of 60 μm.

[0024]

[Table 1] As can be seen from the results in Table 1 above, the larger the cross-section reduction rate, the more significantly the surface roughness increases, and the Au-plated W wire with a thickness of 0.5 μm and the Au-plated W wire with a thickness of 1.5 μm have almost the same roughness. ， In other words, it can be seen that the drawing roughness is unavoidable due to the dice.

Next, A of the surface layer portion of the drawn Au plated wire
The adhesion strength between the u-plating and the W wire in the drawn portion was simply examined. 1 for each drawn wire for each outside diameter (with Au plating)
Prepare m × 10 pieces, hit the die edge-shaped die wire, iron, measure the peeling of the surface layer with a microscope,
Table 2 below shows the number of peeled pieces.

[0026]

[Table 2] As is clear from Table 2 above, at least the working rate is 1.3% or more as drawn by the following equation (1).
It can be seen that the plated W wire does not peel off.

[0027]

[Equation 1] Next, using these drawn Au-plated wires as charging wires, set the drawn Au-plated W wires 1 in the charging wire shield case 2 shown in FIG. Using the equipment shown in, use silicon oil at 140 ℃
The sample was heated to 6000 V forcibly and charged with a silicone oil vapor to 6000 V or less and applied to the charging wire. After 200 hours, the sample (outer diameter 60 μm, 59.5 μm, 59.0 μm, 58.
0 μm) of four types of charging lines were taken out and used as voltage distribution measurement samples.

Next, using the voltage distribution measuring device of FIG.
The voltage distribution within one line was measured by applying 00 volt, and the amount of maximum change was used to check the corona discharge above. In addition, the copy mounting was used to check the presence or absence of white and black streaks. The results are shown in Table 3 below.

[0029]

[Table 3] As shown in Table 3, the occurrence of white and black streaks after 200 hours is a phenomenon that occurs independently of the surface roughness.
It was found that the white / black streaks after the time cleaning disappeared when the area reduction rate was 1.3% or more and the surface roughness was R _max 1.0 μm or less.

Here, the voltage change amount (mV) after cleaning for 200 hours is the change in voltage variation after wiping the adhered SiO ₂ with cotton containing alcohol as shown in FIG. The amount is shown. When this amount of change exceeds a certain voltage, black and white streaks generally occur. (Example 2) Example 1 except that the wet plating was Pt
Similarly to the above, an outer diameter of 89 μm was prepared with a Pt-plated W wire.
The amount of Pt adhered was 1.5 μm, and the same wire drawing as in Example 1 was carried out to examine the surface roughness and peel strength (adhesion strength), and the results are shown in Table 4 below.

[0031]

[Table 4] Although the result of the forced life test of the charged wire is omitted in Table 4 above, the same result as that of the Au-plated W wire is obtained. In this case, the cross-section reduction rate 0.9% shown by the following formula 2 is obtained. It was found that good results can be obtained by performing the above wire drawing.

[0032]

[Equation 2] Similar results were obtained for the noble metals coated with Ru, Rh, Pd, Os, Ir and Ag, and platinum group elements.

The corona discharge charging line of the present invention can be applied to an ionizing discharge line such as an image forming apparatus other than an electrophotographic copying machine or a dust collector, and as the charging line, a W line or a Mo line is used. A conductive material other than the wire can also be used and is not limited to this embodiment.

[0034]

As described above, according to the present invention, in the wire material having the surface layer formed by the coating method, the fine particles are in a state of being adhered. It is possible to provide a wire for a corona discharge electrode and a method for manufacturing the same, which has improved peeling strength and a long life as a copy.

[Brief description of drawings]

FIG. 1 is an electron micrograph showing a metal structure of a wire for a corona discharge electrode according to an example of the present invention.

FIG. 2 is a diagram of an apparatus used for measuring the characteristics of the wire for a corona discharge electrode of FIG. 1, and is a perspective view showing a charging wire shield case.

3 is a cross-sectional view showing a schematic configuration of a silicon adhering device used for measuring the characteristics of the wire for corona discharge electrode in FIG.

FIG. 4 is a diagram showing a voltage distribution measuring device for a wire for a corona discharge electrode in FIG.

FIG. 5 is an electron micrograph showing the SiO ₂ particle structure of a wire with SiO ₂ attached.

FIG. 6 is an electron micrograph showing a metal structure of a wire for a corona discharge electrode according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 W wire rod 2 Charging wire shield case 2a, 2b End fixing member 2c U-shaped plate body 3 Forced silicon adhesion container 5 Ammeter 7 Silicon vapor generation container 8 Silicon oil container 9 Heater 10 Exhaust fan 12 Conductor wire 13 Stainless plate 14 Sensor 15 Voltage recorder 16 High voltage supply device 17 Lead wire

Claims (5)

[Claims] 1. A core wire part made of metal and a surface layer covering the core wire part, wherein the surface layer is made of Au, Pt, Ru, Rh,
A wire rod for a corona discharge electrode, which is made of at least one selected from Pd, Os, and Ag and has a surface roughness of R _max of at least 0.9 μm. 2. The corona discharge electrode wire according to claim 1, wherein the core wire portion is any one of W, Mo and an alloy containing at least one of them. Wire rod. 3. Au, Pt, Ru, Rh, Pd, Os, Ag by a coating method on a core wire made of a refractory metal.
A method for producing a wire rod for a corona discharge electrode, which comprises forming a surface layer made of at least one element selected from the above, and subjecting the surface layer to a wire drawing die at a cross-section reduction rate of at least 1%. 4. A method of manufacturing a wire rod for a corona discharge electrode according to claim 3, wherein the coating method is a plating method,
A method for producing a wire for a corona discharge electrode, which is at least one method selected from a CVD method and a PVD method. 5. The method for manufacturing a wire rod for a corona discharge electrode according to claim 3, wherein the core wire portion is any one of W, Mo and an alloy containing at least one of them. And a method for producing a wire rod for a corona discharge electrode.