JP3427283B2 - Corona discharge electrode and corona charging device using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge electrode which applies a corona discharge phenomenon to uniformly charge an object to be charged, and more particularly to a corona discharge electrode using a non-contact type sharpened electrode. In particular, in an electrophotographic image forming apparatus, a corona discharge electrode using a non-contact type sharpened electrode used for the purpose of charging, transferring, separating, removing charge of a photoconductor, and a corona charging device using the same .

[0002]

2. Description of the Related Art Conventionally, corona discharge electrodes of this type of corona discharge are roughly classified into a wire discharge system and a pin discharge system (pin electrode type, sawtooth electrode type, etc.). The latter is small and generates low ozone, and has recently been used in electrophotographic copying machines, printers and the like. In particular, as shown in FIG. 16, an electrode plate in which a plurality of saw-toothed electrodes 812 are provided on one thin plate member 810 as a discharge part is a USP. 472573
2 and a corona charging device having a structure using the same is disclosed in Japanese Patent Laid-Open No. 63-15272.

[0003]

However, the sharpened electrode as the discharge part according to the above-mentioned proposal is very difficult to manufacture because the tip of the electrode is protruding and bending or bending is likely to occur during manufacturing. Becomes Further, there is a problem that normal discharge cannot be obtained due to breakage or bending during cleaning or replacement during use.

An object of the present invention is to solve the above problems and to provide a method for producing a corona discharge electrode in which the tip of the sharpened electrode is not easily broken or bent during production or use. Further, another object of the present invention is to provide a corona charging device in which the tip of the sharpened electrode of the corona discharge electrode is not easily broken or bent during cleaning or replacement during use.

[0005]

The above object is to provide a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a plating method. It is achieved by the corona discharge electrode characterized by the above (first invention).

Further, the above object is that in a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, the sharpened electrode plate is formed on an insulating substrate by a vapor deposition method. And a corona discharge electrode (2nd invention).

Further, in the corona charging device having a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, the sharpened electrode plate is formed on an insulating substrate by a plating method. It is achieved by a corona charging device characterized in that (3rd invention).

Further, the above object is to provide a corona charging device having a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a vapor deposition method. The present invention is achieved by a corona charging device characterized in that (4th invention).

The structure of the corona discharge electrode of the present invention will be described with reference to FIGS. 1 and 2.

The sharpened electrode plate 10 is composed of a common electrode 11 and sharpened electrodes 12 which are a plurality of discharge parts at one end of the common electrode 11 and have a constant pitch Dp (mm). Provided on top. By the manufacturing method described below, the tip portion 13 of the sharpened electrode 12 does not protrude from the surface of the insulating substrate 20, and the insulating substrate 20
Provided on top. The curvature of the tip portion 13 of the sharpened electrode 12 is R = 40 μm or less. Tip 13 of sharpened electrode 12
And the distance Ds (mm) between the end of the insulating substrate 20 and Ds is Dp.
And is equal to or more than the same distance as the pitch Dp of the tip portion 13,
It does not enter on the insulating substrate 20. When the tip portion 13 enters Dp or more, electric discharge occurs on the creeping surface of the insulating substrate 20, and stable electric discharge cannot be obtained. It is preferable that the tip portion 13 of the sharpened electrode 12 and the end portion of the insulating substrate 20 coincide with each other, that is, Ds = 0.

By forming the sharpened electrode plate 10 on the insulating substrate 20, the sharpened electrode plate 10 can be attached to the photosensitive drum with high accuracy. In particular, since bending, bending, and waviness do not occur, it is possible to obtain uniform chargeability with little discharge unevenness. By forming the tip portion of the tip portion 13 of the sharpened electrode 12 on the insulating substrate 20, this effect becomes particularly remarkable.

The structure of the corona discharge electrode is, as shown in FIG. 2, a corona discharge electrode 1 (FIG. 2A) in which a sharp electrode plate 10 is provided on one surface of an insulating substrate 20, or
Any of the corona discharge electrodes 1b (FIG. 2B) having a structure provided on both sides of the insulating substrate 20 for improving charging performance may be used. In the case of both sides, the tips of the sharpened electrode plates on the front and back sides are formed. The parts may be arranged at the same position, or may be arranged in a staggered manner. Also, in the case of one surface, for example, in order to compensate the cracking of ceramics used as the insulating substrate 20, a reinforcing member 21 such as an insulating resin is provided on the surface opposite to the side where the sharpened electrodes 12 are provided. Corona discharge electrode 1c with a structure attached (Fig. 2
(C)).

The insulating member used for the insulating substrate 20 may be an insulating member used for a conventionally known printed circuit board or the like. However, since a high voltage is applied to discharge, the dielectric strength and tracking are improved. It is preferable to select a material with excellent properties, and the dielectric strength is 5 KV / m
m or more is preferable. The thickness is preferably 0.1 mm to 3 mm, though it depends on the type of material. If it is less than 0.1 mm, there is a problem in linearity and strength, and if it is more than 3 mm, it becomes heavy in weight and installation becomes difficult.

As a preferable insulating member, from the above-mentioned points, it is excellent in strength, linearity and dielectric strength, and in the manufacturing method described later, from the viewpoint of chemical resistance at the time of plating and high temperature resistance at the time of vapor deposition, a ceramic-based material. It is particularly preferable to use the above material.

Alumina (Al
₂ O ₃ ) system, single crystal sapphire (Al ₂ O ₃ ), forsterite (2MgO / SiO ₂ ) system, steatite (Mg)
O / SiO ₂ ) type, zircon (ZrO ₂ · SiO ₂ ) type,
Cordierite _{(2MgO · 2Al 2 O3 · 5SiO} 2)
Series, titania series, silicon carbide (SiC) series, silicon nitride (S
i ₃ N ₄ ) type, zirconia (ZrO ₂ ) type, cermet type, mycarex, soda quartz glass, borosilicate glass, quartz glass and the like are used. These ceramic materials contain 5% by weight to improve the fragility.
It is also possible to use a resin which contains ˜20 wt% of resin and is appropriately imparted with elasticity.

As described above, when the discharge electrode is formed on only one side, the ceramic is liable to be broken due to impact, vibration, stress concentration at the mounting portion, etc. only with ceramics. Therefore, the reinforcement shown in FIG. After forming the discharge electrode, it is preferable to mount an insulating resin as the member 21 on the surface opposite to the surface on which the discharge electrode is formed.
For example, polyester, polyimide, glass epoxy,
Insulating resins such as ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-6-fluoropropylene copolymer, polytetrafluoroethylene, polyamideimide, polysulfol, triazine resin, polyethylene terephthalate, polyurethane, or the like. In addition to composite materials reinforced with glass fiber or the like, materials such as paper phenol and silicone rubber can be used.

FIG. 3 shows an example of the pattern of the sharpened electrode provided on the sharpened electrode plate. As shown in FIG. 3, it is preferable that the portion where the discharge is performed is sharpened, and the sharpened portion is preferable. As a discharge part of the striped electrode plate, a sharpened electrode plate 10 provided with a serrated sharpened electrode 12 and sharpened electrode plates 10b, 1 provided with arrow-shaped sharpened electrodes 12b, 12c are provided.
0c, a sharpened electrode plate 10d provided with a diamond-shaped sharpened electrode 12d, or the like is used.

Next, a method of manufacturing the sharpened electrode plate 10 will be described.

First, the manufacturing method of the sharpened electrode plate provided on the corona discharge electrode of the present invention by the plating method will be described with reference to FIG.

The overall flow of the method for producing a sharpened electrode plate by the plating method is as follows: a) pretreatment of the insulating substrate, b) resist preparation, c) electroless plating, as schematically shown in FIG. The order is d) preparation of a sharp electrode plate pattern by electrolytic plating, and e) cleaning, which is substantially the same as the conventionally known plating technique.

A) Pretreatment The insulating substrate 20 is pretreated so that the metal is easily deposited on the insulating substrate 20 by plating. As a pretreatment, the following three steps are performed.

To remove oils and fats and stains such as fingerprints adhering to the insulating substrate, an aqueous solution of an inorganic or organic acid such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, formic acid or acetic acid, or sodium hydroxide or carbonic acid. A degreasing step in which an alkaline aqueous solution of sodium, sodium phosphate or the like is impregnated at 60 ° C. to 65 ° C. for about 10 to 20 minutes.

A surface roughening step of chemically or mechanically roughening the surface of the insulating substrate in order to improve the adhesion between the deposited metal and the insulating substrate. When an insulating resin, which will be described later, is used as the insulating substrate, chemical roughening is generally performed using a sulfuric acid-chromium solution, a permanganate curry phosphoric acid mixed solution, or the like. However, when an inorganic material such as ceramic is used, chemical roughening cannot be performed, and mechanical roughening also causes cracks and the like, so that it is not always necessary.

An activation step of adsorbing tin ions having a strong reducing power, for example, on the insulating substrate so that the electroless plating is deposited on the insulating substrate in the subsequent step. There are the following two main methods of the activation process.

Sensitizer activator method: After immersing the substrate in an aqueous solution of stannous chloride and hydrochloric acid for 1 to 5 minutes,
Immerse in an aqueous solution of palladium chloride and hydrochloric acid for 1 to 5 minutes.

Catalyst method: Immerse in a colloidal hydrochloric acid solution of palladium chloride and stannous chloride for 1 to 3 minutes.

B) Preparation of Resist Before the plating, the sharp electrode plate 1 is placed on the insulating substrate 20.
Resists 102 and 103 corresponding to the pattern 01 are prepared. As a means for forming the resists 102 and 103, a conventionally known photoetching method, an etching resist forming method by screen printing or the like can be used, but the photoetching method is preferably used from the viewpoint of accuracy. As the resist material, the following materials are preferably used. Similar to the method for producing a printed circuit board of the adjective system, any resist material is applied to the insulating substrate 20 to form a sharpened material. The portion corresponding to the pattern of the electrode plate 101 is not cured but removed by cleaning, and plating is deposited on that portion in the next electroless plating process to form the pattern of the sharpened electrode plate 101. When the sharp electrode plates are formed on both surfaces, the same steps are performed on both surfaces of the insulating substrate 20.

As the resist material, negative type polyvinyl alcohol-dichromate, shellac-dichromate, casein-dichromate, polyvinyl alcohol-
Diazo, acrylic, polyvinyl cinnamate, cyclized rubber-
Azide, polyvinyl cinnamylidene acetate, polycinnamic acid vinyl-β-vinyloxyethyl ester, azido polymer, and positive o-naphthoquinone azide are used.

C) Electroless plating of the insulating substrate 20 having the electroless plating resist is performed. Although there are various metals used for plating as shown below, electroless copper plating using copper sulfate is generally most widely used because it is easily deposited and has high adhesion. p
While carefully paying attention to H and the liquid temperature, the insulating substrate 20 is immersed in the electroless plating solution 105a in the bath 104a, and after sufficient plating is formed on the pattern of the sharpened electrode plate 101, the resist is alkalinized. Etc., removal, washing with water,
Dry.

As the liquid composition, when copper is used as the metal, copper sulfate, Rossell salt, formalin and sodium hydroxide are used, and when nickel is used as the metal, nickel sulfate, sodium acetate and hypophosphorus are used. Sodium acid, sodium citrate, lactic acid, and lactic acid are used. In addition, tin (first tin chloride), chromium (chromium bromide, chromium chloride), cobalt (cobalt chloride), cobalt-nickel (cobalt chloride-nickel chloride), iron (ferrous sulfate),
It is possible to perform plating with a metal such as silver (silver nitrate).

D) Electrolytic plating After the pattern of the sharpened electrode plate 101 is formed by electroless plating, the pattern is electrolessly plated in order to prevent rust, corrosion, and impart sufficient conductivity. Electrolytic plating may be performed as the cathode. The insulating substrate 20 is immersed in the electrolytic plating solution 105b in the bath 104b to form plating on the pattern of the sharpened electrode plate 101. Reference numeral 106 is an electrode plate. Before performing electroplating, degreasing, pickling, washing with a surfactant, washing with water, and drying are performed on the electroless plated portion. Electrolytic plating can be performed by a conventionally known method, and as the electrode plate 106, copper, nickel, chromium, zinc, cadmium, tin, gold, gold alloy, silver, rhodium, or the like can be used. Copper, gold, rhodium and the like are preferably used. The electrolytic plating solutions are shown in Tables 1 to 3.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

E) Cleaning / Resist Removal After completion of electroless plating or electrolytic plating, cleaning, resist removal with alkali, cleaning and drying are performed to obtain a corona discharge electrode on which the pattern of the sharpened electrode plate 101 is formed. Alternatively, a method of forming the sharpened electrode plate 101 only by electroless plating can be used.

In such a plating method, since the sharpened electrode can be formed relatively thick (several tens of μm), the sharpened electrode having high dischargeability from the tip portion and excellent durability is required. You can

Secondly, FIG. 5 shows the method of manufacturing the sharpened electrode plate provided on the corona discharge electrode of the present invention by the vapor deposition method.
~ It demonstrates using FIG.

The general flow of the method for producing a sharpened electrode plate by vapor deposition is as follows: a) removal of substrate stains, b) resist fabrication, and c) electrode pattern fabrication by vapor deposition. This is in the order of, and is substantially in accordance with the conventionally known metal thin film manufacturing technology.

A) Pretreatment The dirt on the insulating substrate 20 is removed so that the conductor is easily deposited on the insulating substrate 20. As a method, pickling,
A heating method of heating in a vacuum, a sputtering method of causing accelerated Ar ions to collide, and the like are used, but generally, the following two types of methods are preferably used.

B) Preparation of resist Before the deposition, the sharp electrode plate 20 is formed on the insulating substrate 20.
Resists 202 and 203 corresponding to the pattern 1 are manufactured. As a means for forming the resists 202 and 203, a conventionally known photoetching method, an etching resist forming method by screen printing, or the like can be used, but the photoetching method is preferably used from the viewpoint of accuracy. Although the following resist materials are preferably used, whichever resist material is used, the resist material is applied onto the insulating substrate 20 and the portion corresponding to the pattern of the sharpened electrode plate 201 is cured. Instead, it is removed by cleaning, and a conductive member is deposited on that portion in the next vapor deposition step to form the pattern of the sharpened electrode plate 201. When the sharp electrode plates are formed on both surfaces, the same steps are performed on both surfaces of the insulating substrate 20.

As the resist material, negative type polyvinyl alcohol-dichromate, shellac-dichromate, casein-dichromate, polyvinyl alcohol-
Diazo, acrylic, polyvinyl cinnamate, cyclized rubber-
Azide, polyvinyl cinnamylidene acetate, polycinnamic acid vinyl-β-vinyloxyethyl ester, azido polymer, and positive o-naphthoquinone azide are used.

Further, depending on the type of vapor deposition method, for example, the CVD method, the insulating substrate may reach a very high temperature. Therefore, a metal such as molybdenum and kovar, graphite, It is preferable that a mask 204 made of glass is prepared and placed on the insulating substrate 20 to form a sharpened electrode plate.

C) Preparation of electrode pattern by vapor deposition method The vapor deposition method is roughly classified into PVD method (physical).
vapor deposition, CVD method (ch
Although there are two types, the former method is preferably used in the present invention because the temperature of the insulating substrate at the time of depositing the conductive member 205 is low. Table 4 shows the conductive members used in the PVD method.

[0044]

[Table 4]

Although the sharpened electrode plate is formed by using these methods, it is not always necessary to use only a single metal. For example, in order to prevent moisture absorption of the insulating substrate and oxidation of the insulating substrate by the air, You may vapor-deposit on the flexible substrate in the order of titanium, copper, and gold. Among the following methods, the vacuum vapor deposition method and the sputtering method are most often used. PVD method Providing heat, physical energy (eg heat, laser, energetically stressed atoms, molecules, ions, etc.),
The PVD method dissociates and vaporizes atoms and molecules on the solid surface and deposits them on an insulating substrate. The PVD method suitable for the present invention will be described.

In the vacuum vapor deposition method, as shown in FIG. 6, a material substance (conductive member) 511 is heated in a vacuum to evaporate or sublimate, and the vapor is transported onto an insulating substrate 512 at a relatively low temperature. Then, it is condensed and deposited to form a sharp electrode plate. The atmospheric pressure is 10 ⁻³ Torr to 10 ⁻¹¹ Torr, and is generally around 10 ⁻⁶ Torr. For heating the conductive member, tungsten, tantalum, or molybdenum is preferably used as an evaporation source. In addition, heating with an electron beam or a laser beam can also be performed.

In the sputtering method, the conductive member 521 is composed of particles (atoms, molecules, ions) that are energetically stressed in a vacuum.
The surface of the electrode is hit to release atoms, molecules, and clusters on the surface of the conductive member and deposited / deposited on the insulating substrate 522 to form a sharpened electrode plate. Atmospheric pressure is 1 Torr to 10
^-6 Torr is generally around 10 ^-2 Torr.
Ar is most often used as the sputtering ions. Generally, a two-station DC sputtering device shown in FIG. 7,
The high frequency sputtering apparatus shown in FIG. 8 is often used.

In the ion plating method, as shown in FIG. 9, in a vacuum chamber, A of 10 ^-1 Torr to 10 ^-4 Torr was used.
A voltage of 100V to several KV is applied between the conductive member (anode) 531 and the cathode on which the insulating substrate 532 is placed (the cathode side is raised) by r gas, and the insulating substrate is sputter cleaned by argon ions. At the same time, the conductive particles evaporated by heating are accelerated and ionized by a high electric field and discharge (glow discharge), and are deposited on the insulating substrate to form a sharp electrode plate.

In addition, an ion beam sputtering method in which the surface of a conductive member is hit with an ion beam to perform sputtering, an ion beam method in which a film is formed on a substrate by the ion beam itself, a cluster ion method, or the like can be used.

CVD Method As a typical structure, as shown in FIG. 10, the CVD method is a method in which a volatile substance 541 is used as a raw material and a product (conductive member) is deposited on an insulating substrate 542 through a chemical reaction. . Table 5 shows the raw material gas and the product.

[0051]

[Table 5]

In addition, plasma CVD method, MOCDV method using organic metal gas as a raw material, MBE (Molecular)
r Beam Epitaxy) method or the like can be used. However, since the system may have a relatively high temperature (500 ° C. to 1000 ° C.) in some cases, ceramic is used as the insulating substrate, and resin resist is used as the masking material. Instead, it is preferable to form a sharp electrode plate by placing a mask made of metal such as molybdenum or kovar, graphite, or glass on the substrate.

In such a vapor deposition method, since a sharp electrode having a sharp edge is formed with a high-purity metal, it is necessary to form a sharp electrode which is less likely to cause discharge unevenness and leakage and has excellent charging stability. You can

A corona charging device using the corona discharge electrode formed by the above method will be described with reference to FIGS. 11 to 14.

The sharpened electrode plate 10 is composed of a common electrode 11 and sharpened electrodes 12 which are a plurality of discharge parts at one end of the common electrode 11 at a constant pitch Dp (mm). The corona discharge electrode 1 provided on the insulating substrate 20, for example, ceramic is used for an electrophotographic image forming apparatus without the tip portion 13 of the sharpened electrode 12 protruding from the surface of the insulating substrate 20. The photosensitive drum 7, which is an image forming body, is arranged orthogonal to the moving direction indicated by the arrow. The curvature of the tip portion 13 of the sharpened electrode 12 is R = 40 μm or less. The distance Ds (mm) between the tip portion 13 of the sharpened electrode 12 and the end portion of the insulating substrate 20 is Dp or less, and the tip portion 1
3 does not penetrate into the insulating substrate 20 for the same distance as the pitch Dp. When the tip portion 13 enters Dp or more, electric discharge occurs on the creeping surface of the insulating substrate 20, and stable electric discharge cannot be obtained. Preferably, the tip portion 13 of the sharpened electrode 12 and the end portion of the insulating substrate 20 coincide with each other, that is, Ds = 0.
Is desirable. The control grid 5 is, for example, made by etching a stainless steel plate having a plate thickness of 0.1 mm, and the side plates 3 and 4 which are shield members are formed of, for example, one stainless steel plate. It is a thing.

The corona discharge electrode 1 is dropped into the groove 2a of the supporting member 2 made of an insulating resin such as ABS resin, and fixed with an adhesive, for example. Side plate 3,
4 are attached and fixed to both ends of the supporting member 2 in parallel with the longitudinal direction of the corona discharge electrode 1 by, for example, resin screws (not shown), and a control grid 5 is attached to both ends of the supporting member 2 for attaching control grids. The scorotron charger 100, which is a corona charging device, is formed on the surfaces 2b and 2c by, for example, attaching and fixing it with a resin screw (not shown).

The scorotron charger 100 described above is attached so as to face the photosensitive drum 7, but the sharpened electrode plate 10 is attached downstream of the photosensitive drum 7 in the rotational direction of the photosensitive drum 7. Because the discharge spreads to
Charge is stable, which is particularly preferable. When the image is formed,
The DC voltage E1 is applied to the sharpened electrode plate 10 by the control grid 5
Is applied to the side plate 4 on the side where the sharpened electrode plate 10 is provided.

When the distance Dp between the tips 13 of the sharpened electrodes 12 is set to 1 mm or less, electric discharge occurs to the adjacent sawtooth electrodes, resulting in significant charging unevenness. When the distance Dp between the tips 13 of the sharpened electrodes 12 is set to 4 mm or more, the discharges from the adjacent sawtooth electrodes do not overlap with each other and unevenness occurs according to the pitch of the sawtooth electrodes, and the discharges from the sawtooth electrodes are completely independent. Then, it reaches the photosensitive drum and the charging unevenness is severe.

As shown in FIG. 13, the distance Dp between the tips 13 of the sharpened electrodes 12 so that uneven discharge is not generated is set to 1.
If the distance is not less than 4 mm and not more than 4 mm, the distance to the points where the radial spreads of the corona discharge intersect each other is doubled.
By arranging the control grid 5 at a position where the value Dg of the distance between and becomes 2Dp or more, the adjacent sharp electrode 12
Since the discharge from the battery reaches the control grid 15 in a state of overlapping, the controllability of the control grid is improved, and a uniform discharge state can be obtained.

By forming the sharpened electrode plate 10 on the insulating substrate 20, the sharpened electrode plate 10 can be attached to the photosensitive drum 7 with high accuracy. In particular, since bending, bending, and waviness do not occur, it is possible to obtain uniform chargeability with little discharge unevenness. Sharpened electrode 12
By forming the tip portion of the tip portion 13 on the insulating substrate 20, this effect becomes particularly remarkable.

The above-mentioned sharp electrode plate 10 does not necessarily need to be installed vertically to the photosensitive drum 7, and in order to obtain a stable discharge by widening the discharge surface, as shown in FIG. The scorotron charger 100b installed by tilting to the side having the electrode 12 may be used, and when the corona discharge electrode 1 is installed by tilting, the same relationship as the above is given by Dp.
And Dg.

Further, as the corona charging device, in addition to the corona discharge electrode 1 provided on one surface with the sharp electrode plate 10 described in the above embodiment, the sharp electrode plate 10 as shown in FIG. 2 is used. The corona discharge electrode 1b provided on both sides or the corona discharge electrode 1c having the reinforcing member 21 fixed to the corona discharge electrode 1 provided with the sharpened electrode plate 10 on one side may be attached.

[0063]

【Example】

Example 1 The insulating substrate 20 was activated by tin ions,
A corona discharge electrode 1 was manufactured by forming a sharp electrode plate 10 on an alumina (Al ₂ O ₃ ) ceramic having a thickness of 1 mm by electroless plating using copper sulfate and then electrolytic plating using copper sulfate. . Table 6 shows the electroless plating solution and Table 7 shows the electrolytic plating solution.

[0064]

[Table 6]

[0065]

[Table 7]

A reinforcing member made of glass epoxy having a thickness of 0.2 mm is attached to the entire surface of the side on which the sharpened electrode plate 10 is not formed with an adhesive, and the corona discharge electrode 1c is formed.
Was produced.

Using the scorotron charger 100 shown in FIG. 11 provided with the corona discharge electrode 1c having the structure shown in FIG. 2C, the sharp electrode 12 is formed.
The distance Dp between the tip portions 13 of the electrodes is 3 mm, and the distance Ds between the tip portions 13 of the sharpened electrodes 12 and the ends of the insulating substrate 20 is 0.2.
mm, the value Dg of the distance between the tip 13 of the sharp electrode 12 and the control grid 5 is 7 mm, and -4.7 kV is applied to the sharp electrode plate 10 of R = 30 μm of the tip 13 of the sharp electrode 12.
(DC) is applied, and -800V (D
C) is applied and the surface potential of the photosensitive drum 7 is -800V.
In order to maintain effective controllability of the control grid 5, the side plate 4 on the side of the sharpened electrode plate 10 is applied with −600 V (DC), which is lower than the voltage applied to the control grid 5, and the result of the experiment. A uniform charging property was obtained.

Example 2 As the insulating substrate 20, 1 mm thick alumina (Al
Corona discharge electrode 1 was manufactured by depositing titanium, copper and gold in this order on the ₂ O ₃ ) ceramic by the apparatus shown in FIG. Sharp electrode plate 10
A reinforcing member made of glass epoxy and having a thickness of 0.2 mm was attached to the entire surface on which no corona was formed by an adhesive to form a corona discharge electrode 1c.

E1 = -5.5 using the scorotron charger 100 shown in FIG. 11 provided with the corona discharge electrode 1c having the structure shown in FIG. 2 (C).
kV (DC), E2 = -800V (DC), E4 = -6
As a result of an experiment at 00V (DC), uniform charging property was obtained.

Example 3 As the insulating substrate 20, 1 mm thick alumina (Al
_A corona discharge electrode 1 was manufactured by forming a sharpened electrode plate 10 of copper on ₂ O ₃ ) by a CVD method using CuCl ₃ as a raw material gas by the apparatus shown in FIG. Sharp electrode plate 10
A reinforcing member made of glass epoxy and having a thickness of 0.2 mm was attached to the entire surface on which no corona was formed by an adhesive to form a corona discharge electrode 1c.

Experiments were conducted under the same experimental conditions as in Example 2 using the scorotron charger 100 shown in FIG. 11 provided with the corona discharge electrode 1c having the structure shown in FIG. 2C. As a result, uniform chargeability was obtained.

Example 4 (Double-sided electrode) Electrolytic plating using copper sulfate and then electrolytic plating using copper sulfate were performed on both sides of an alumina (Al ₂ O ₃ ) ceramic having a thickness of 3 mm to form a sharpened electrode plate. Formed 10. At this time, the corona discharge electrode 1 having the structure shown in FIG. 2B is formed by shifting the positions by 1/2 pitch so that the tips 13 of the sharp electrodes 12 on both sides do not overlap.
b was manufactured and an experiment was performed using the scorotron charger 100c having the cross-sectional shape shown in FIG. Dp = 3 mm, Ds =
0.4 mm, Dg = 6.5 mm, R = 30 mm, E
1 = 3.5KVDC, E2 = -800VDC, E3 = E
4 = -600V. A more uniform charging property was obtained.

Comparative Example (Sharp Electrode without Insulating Substrate) Instead of the sharp electrode plate used in the examples, the thickness is 0.1 m.
Charging was performed using a scorotron charger using a sharp electrode formed by etching a stainless steel plate of m. Dp = 3 mm, Dg = 7 mm, E1 = -4.5 KV
(DC), E2 = -800V, E3 = E4 = -600V
And

An image density of 0.8 (Macbeth) was used as an evaluation method for uniform charging according to the above-mentioned Examples and Comparative Examples.
A halftone of Macbeth densitometer RD-918 manufactured by Co., Ltd. is output on the paper, and density unevenness in the vertical direction with respect to the conveyance is measured with an image analyzer (RT-20.
00C, manufactured by Yerman Co., Ltd., and the standard deviation thereof was calculated and compared. Table 8 shows the results.

[0075]

[Table 8]

The smaller the standard deviation (closer to 0), the smaller the variation and the more uniform the charging.

Of course, the corona charging device using the corona discharge electrode provided with the sharpened electrode plate is a transfer / separation device other than the charger in the electrophotographic image forming apparatus,
It can be used as a static eliminator or the like, and can also be used in fields other than electrophotography.

[0078]

According to the first aspect of the present invention, the sharpened electrode plate having the sharpened electrode is formed on the insulating substrate by the plating method. By using such a manufacturing method, a sharpened electrode is formed without protruding from the insulating substrate, and a corona discharge electrode that is easy to handle and is easy to handle with no breakage, bending, etc. can be obtained accurately and easily. You can Further, since it is possible to use the same chemicals, base materials, and processing equipment as in the conventionally known plating method, it is possible to easily obtain a corona discharge electrode at low cost. In addition, the sharp electrode is relatively thick (tens of μ
m) Since it can be formed, it is possible to form a sharp electrode having high dischargeability from the tip and excellent durability.

According to the second aspect, the sharpened electrode plate having the sharpened electrode is formed on the insulating substrate by the vapor deposition method. By using such a manufacturing method, a sharpened electrode is formed without protruding from the insulating substrate, and a corona discharge electrode that is easy to handle and is easy to handle with no breakage, bending, etc. can be obtained accurately and easily. You can Further, since it is possible to use the same chemicals, base materials, and processing devices as those used in the conventionally known thin film forming method (vapor deposition method), a corona discharge electrode can be easily obtained at low cost. In addition, since a sharp electrode having a very sharp edge is formed of a high-purity metal, it is possible to form a sharp electrode that is less likely to cause uneven discharge and leak and has excellent charging stability.

According to the third aspect, it is particularly preferable in terms of strength, linearity, dielectric strength, and chemical resistance during plating.

According to the fourth aspect, stable and uniform charging performance can be obtained.

According to the fifth aspect, the easiness of cracking of the insulating substrate, especially the susceptibility of the ceramic to cracking can be compensated.

According to the sixth aspect, a corona discharge electrode can be obtained in which the tip of the sharpened electrode is not easily bent or bent during manufacture or use. Further, by forming the sharpened electrode plate on the insulating substrate, the sharpened electrode plate can be attached to the photoconductor with high accuracy, and in particular, the tip of the sharpened electrode plate provided on the sharpened electrode plate. By forming the portions on the insulating substrate without protruding from the insulating substrate, bending, bending, and waviness do not occur, and uniform chargeability with less discharge unevenness can be obtained.

According to the seventh aspect, it is possible to obtain a corona charging device in which the tip of the sharpened electrode is not easily bent or bent during cleaning or replacement during use. Further, since the sharpened electrode can be formed relatively thick (several tens of μm), it is possible to obtain a corona charging device having a sharpened electrode having high dischargeability from the tip portion and excellent durability.

According to the eighth aspect, it is possible to obtain a corona charging device in which the tip end of the sharpened electrode is not easily broken or bent during cleaning or replacement during use. In addition, since a sharp electrode having a sharp edge is formed of a metal of high purity, it is possible to obtain a corona charging device having a sharp electrode which is less likely to cause uneven discharge and leak and has excellent charging stability.

According to the ninth aspect, it is possible to obtain a corona charging device which is particularly preferable in terms of strength, linearity, dielectric strength, and chemical resistance during plating.

According to the tenth aspect, it is possible to obtain a corona charging device that can stably obtain uniform charging performance.

According to the eleventh aspect, it is possible to obtain a corona charging device which compensates the cracking of the insulating substrate, particularly the cracking of the ceramic.

According to the twelfth aspect, at the time of manufacture or use,
It is possible to obtain a corona charging device in which the tip of the sharpened electrode is easily broken and is not bent. Further, by forming the sharpened electrode plate on the insulating substrate, the sharpened electrode plate can be attached to the photoconductor with high accuracy,
In particular, since the tip of the sharpened electrode provided on the sharpened electrode plate is formed on the insulating substrate without protruding from the insulating substrate, bending, bending, or waviness does not occur, and therefore, uneven discharge occurs. It is possible to obtain a less uniform charging property.

[Brief description of drawings]

FIG. 1 is a diagram showing a corona discharge electrode of the present invention.

FIG. 2 is a diagram showing a structural example of a corona discharge electrode.

FIG. 3 is a view showing a pattern of a sharpened electrode.

FIG. 4 is a diagram showing a flow of a method for manufacturing a sharpened electrode plate by a plating method.

FIG. 5 is a diagram showing a flow of a method for manufacturing a sharpened electrode plate by a vapor deposition method.

FIG. 6 is a diagram showing a vacuum vapor deposition device.

FIG. 7 is a diagram showing a two-station DC sputtering apparatus.

FIG. 8 is a diagram showing a high frequency sputtering device.

FIG. 9 is a diagram showing an ion plating method.

FIG. 10 is a diagram showing a CVD method.

FIG. 11 is a sectional configuration diagram of a scorotron charger using the corona discharge electrode of the present invention.

12 is an assembly diagram of the scorotron charger of FIG. 11. FIG.

FIG. 13 is a diagram showing a discharge state of a scorotron charger.

FIG. 14 is a view showing a scorotron charger in which corona discharge electrodes are obliquely attached.

FIG. 15 is a diagram showing a scorotron charger having a double-sided electrode structure.

FIG. 16 is a diagram showing a conventional sawtooth electrode plate.

[Explanation of symbols]

1, 1b, 1c Corona discharge electrode 2 Support member 3, 4 Side plate 5 Control grid 7 Photosensitive drum 10, 10b, 10c, 10d, 101, 201 Sharp electrode plate 12, 12b, 12c, 12d Sharp electrode 13 Tip Part 20, 512, 522, 532, 542 Insulating substrate 21 Reinforcing member

Front page continuation (72) Inventor Satoshi Haneda 2970 Ishikawa-cho, Hachioji City, Tokyo Konica Co., Ltd. (56) References JP-A-6-35294 (JP, A) JP-A-63-307479 (JP, A) ) JP 5-94078 (JP, A) JP 5-204226 (JP, A) JP 5-224507 (JP, A) JP 6-3923 (JP, A) JP 4- 14784 (JP, A) JP-A-4-233560 (JP, A) JP-A-7-181781 (JP, A) JP-A-7-5746 (JP, A) JP-A-6-130831 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/02 G03G 15/16 101 H01T 19/04

Claims (12)

(57) [Claims] 1. A corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a plating method. electrode. 2. A corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a vapor deposition method. electrode. 3. The corona discharge electrode according to claim 1, wherein the insulating substrate is ceramic. 4. The corona discharge electrode according to claim 1, wherein the sharpened electrode plates are provided on both surfaces of the insulating substrate. 5. The reinforcing member for the insulating substrate is provided on the surface of the insulating substrate opposite to the surface on which the sharpened electrode plate is provided. Or 1
The corona discharge electrode according to the item. 6. The corona discharge electrode according to claim 1, wherein a tip portion of the sharpened electrode does not protrude from the insulating substrate. 7. A corona charging device having a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a plating method. Characteristic corona charging device. 8. A corona charging device having a corona discharge electrode provided with a sharpened electrode plate having a plurality of sharpened electrodes, wherein the sharpened electrode plate is formed on an insulating substrate by a vapor deposition method. Characteristic corona charging device. 9. The corona charging device according to claim 7, wherein the insulating substrate is ceramic. 10. The corona charging device according to claim 7, wherein the sharpened electrode plates are provided on both surfaces of the insulating substrate. 11. The reinforcing member for the insulating substrate is provided on the surface of the insulating substrate opposite to the surface on which the sharpened electrode plate is provided. The corona charging device according to item 1. 12. The corona charging device according to claim 7, wherein a tip portion of the sharpened electrode does not protrude from the insulating substrate.