JP2002040757A - Ion generator, method and device for electrifying, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a reduction of ozone at the place of an ion generating part, without additionally installing an ozone filter and a heating mechanism, in the ion generator used for an electrifying device for an image forming device. SOLUTION: As for the ion generator, a dielectric 8 is arranged between conductive electrodes 6 and 7, and the generator is provided with an electrode structure with a fine discharge space which is formed to almost a closed space sandwiched by them, and an AC voltage is applied between the conductive electrodes by an AC power supply 11, and then, charged particles are generated by discharging, and as for the dielectric 8, the value of the dielectric dissipation factor out of high frequency dielectric characteristics is >=30×10-4. Besides, the ion generator is constituted of two kinds of elements, that is, an element 1 constituted of a member having the high dielectric dissipation factor and an element 2 constituted of a member having the low dielectric dissipation factor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to the ozone and nitrogen oxides (NO _X) ion generator for generating charged particles without generating toxic product, such as, and, electrophotographic recording, such as copiers and printers Carrier such as a photoreceptor (charged body) using the above-mentioned ion generator in an image forming apparatus of a system
More particularly, the present invention relates to a charging method and a charging device for charging an image carrier such as a photoreceptor using charged particles (electrons and ions) generated by electric discharge and without generating harmful products such as ozone due to electric discharge. The present invention relates to a charging method and a charging device for charging. The present invention also relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile, and a plotter using the ion generator, the charging method, or the charging device. Further, the ion generator of the present invention uses charged particles generated by space discharge between electrodes for charging, and further changes the discharge conditions (applied voltage, electrode arrangement, etc.) and the structure to form an image forming apparatus. It can also be used as a charge (ion) generator used for transferring and removing electricity. On the other hand, although the application fields for application are different, space discharge generates a large number of charged particles and reactive neutral particles that retain high energy, and therefore harmful substances such as volatile organic compounds (VOCs) floating in the atmosphere. It can also be used as a reactor for decomposing and removing substances.

[0002]

2. Description of the Related Art Standards such as UL standards, TUV standards, and BAM standards have been set by a plurality of organizations in a plurality of countries and regions to regulate the amount of ozone generated for electrophotographic image forming apparatuses. Therefore, reducing the generation of ozone in a charging device or the like has become an important issue. Further, in an image forming apparatus, a substance caused by nitrogen oxides (NO _x ) generated by the discharge of the charging device adheres to the photoreceptor and absorbs moisture, thereby lowering the surface potential of the photoreceptor, thereby generating a defective image. Is a problem.

Conventionally, copiers, printers, facsimile machines,
Used in an electrophotographic image forming apparatus such as a plotter,
Examples of a charging device for charging a photosensitive member as an object to be charged include a corona charger, a roller charger, a brush charger, and a solid charger. Of these, the corona charger is the most widely used charging method. However, the corona charger, for non-contact charging method utilizing corona discharge in air, there is a problem of generating a large number of ozone and NO _X.
Therefore, in order to solve this problem, for example, a corona charger designed to reduce the amount of generated ozone is disclosed in Japanese Patent Laid-Open No. 9-11 / 1991.
No. 4192. This corona charger reduces the amount of generated ozone to 50% or less by performing discharge using a very fine wire of 40 to 50 microns (μm). Japanese Patent Application Laid-Open No. 6-324556 has a metal housing disposed so as to surround three sides of a wire, and a metal mesh electrode disposed near an opening of the metal housing. A corona charger is described that reduces the amount of released ozone by increasing the probability of confinement and collision of ozone molecules. However, Japanese Patent Application Laid-Open Nos. Hei 9-114192 and Hei 6-32
In the corona charger described in JP-A No. 4556, which reduces the amount of ozone, the amount of ozone can be reduced at most by about 50%. Treatment such as use was necessary.

As one method of reducing ozone generated by a charging device such as a corona charger, a method using an ozone adsorbent is known. This ozone adsorbent converts ozone generated by a charging device into activated carbon or the like. It is used to oxidize by the catalytic function or to be adsorbed on the surface. However, when an ozone adsorbent is used in combination, the amount of ozone can be reduced, but the ozone adsorbent has a problem that it requires replacement and maintenance of an ozone filter because of deterioration over time, which increases costs.

On the other hand, roller chargers have been disclosed in
This is one of the contact charging methods that have been actively studied in recent years. Since the roller charger is a system in which a charged roller is brought into contact with an object to be charged to perform charging, the generation of ozone can be extremely reduced, and thus the roller charger is considered promising. However, the roller charger can generate very little ozone due to the contact charging method,
There is a problem that charging is likely to be non-uniform, and when used in an electrophotographic image forming apparatus, toner contamination on the roller surface, vibration due to a bias AC applied to the roller, and image moire are likely to occur. In addition, the roller charger is a rotating body, and the cleaning of the roller surface requires cleaning, so there are many members and a problem that the manufacturing cost is high. There is a problem that a pinhole is apt to be generated due to breakage, a charging roller trace due to a vibration noise, a plasticizer or the like, a permanent deformation of the roller, and the like are easily generated.

A brush charger is disclosed in Japanese Patent Publication No. 55-29837.
This is one of the contact charging systems. Since this brush charger performs charging by bringing a charged brush into contact with an object to be charged, generation of ozone can be extremely reduced. However, since the brush charger is a contact charging system, streaky charging unevenness and uneven charging due to environmental fluctuations are likely to occur, and low-temperature streamer discharge, white spots,
There are drawbacks such as abrasion of the photoreceptor, accumulation of abrasion photoreceptor, removal of the brush, etc., and melting of the brush which is considered to be caused by abnormal discharge due to scratches on the photoreceptor.

[0007] The solid-state charger has been described in Japanese Patent Application Laid-Open No. 54-535.
No. 37, for example. Also, Japanese Unexamined Patent Publication No.
Japanese Patent Application Laid-Open No. 94077 discloses an apparatus in which a large number of discharge electrodes are provided on an insulating member at minute intervals. Further, Japanese Patent Application Laid-Open No. 6-75457 discloses that the distance between the charger and the recording medium is set to 500 to 3000 μm, thereby shortening the flight distance of ions and suppressing the diffusion of ozone, and the toner and the like. What prevents adhesion is described. Japanese Patent Application Laid-Open No. 9-244350 describes a discharge device provided with a discharge electrode on a plate-like substrate, a creeping glow discharge means disposed on the outer periphery thereof, and a cover for covering the entire charger. JP-A-9-115646, it is described that reduce of the NO _X by using a material of a specific work function electrode material in a planar type solid-state discharge device. These solid-state chargers are expected to be less likely to deteriorate, break, or be contaminated as corona discharge electrodes, and have the advantage of being able to reduce the size of the device. There easily diffused, not be the reduction of unpleasant substances such as ozone and nO _X as expected.

[0008]

[SUMMARY OF THE INVENTION The present invention is to provide an ion generator capable of reducing the generation of discharge products such as the ozone and NO _X, and the charged using the ion generator An object of the present invention is to provide a charging method and a charging device for charging an object. Further, in the present invention, using the ion generator or charging method or charging apparatus to reduce the generation of discharge products such as ozone and NO _X,
It is an object of the present invention to provide an image forming apparatus that satisfies standards such as UL standard, TUV standard, and BAM standard. Hereinafter, the problems to be solved by the claimed invention will be described in more detail.

(1) Problems to be solved by the invention of claim 1 As a means for suppressing the generation of ozone which is not directly involved in the charging action and is released into the air as a harmful substance in ion generation by gas ionization, removal by an ozone adsorption filter and ozone decomposition by heating are known. However, the installation of the filter has a limited period of its effect, and regular maintenance is inevitable. On the other hand, providing a separate heating means is difficult in terms of the design of the charging device, and is not preferable in terms of power consumption of the device. In view of the above, an object of the present invention is to provide an ion generator capable of reducing ozone on the spot of an ion generator without providing an ozone filter or a heating mechanism.

(2) Problems to be solved by the invention of claim 2 It is an object of the present invention to suppress ozone emission by promoting the decomposition of ozone released into the air as a harmful substance without being directly involved in the charging action of ion generation by gas ionization. The charged particles generated by the gas ionization due to the discharge are used for the charging action, the discharge stability is maintained, and the thermal influence on the charged object such as the image carrier (photoconductor) to be charged is avoided. It is an object of the present invention to provide an ion generator capable of performing the above. In addition, gas ionization due to discharge generates many ions and neutral excited species,
Excessive input of electric energy for discharge promotes not only ozone but also a large amount of nitrogen oxide (NO _x ), which is said to adversely affect the image carrier. Therefore, in the second aspect of the present invention, the amount of charged particles necessary and sufficient for charging is secured by optimizing the use efficiency of electric energy, and heat and unpleasant discharge products affecting the image carrier are minimized. Therefore, an object of the present invention is to provide an ion generator having a configuration that solves this problem.

(3) Problems to be solved by the invention of claim 3 According to the third aspect of the present invention, there is provided the same problem as in the second aspect, and it is possible to secure a sufficient amount of charged particles generated by gas ionization due to discharge for a charging operation, and to secure a charging speed capable of withstanding high-speed processing. It is an object to maintain discharge stability and to avoid thermal influence on an image carrier (photoconductor) to be charged. In view of the above, an object of the present invention is to provide an ion generator configured to solve the above-mentioned problem.

(4) Problems to be solved by the invention of claim 4 In the ion generator, ozone generated intensively in the ion generating portion is prevented from diffusing to the outside, and generation of unpleasant discharge products and reduction of power consumption, which are difficult to stably maintain the discharge at a low voltage. It is necessary for In view of the above, the invention of claim 4 provides an ion generator having a configuration capable of preventing ozone generated intensively in an ion generating portion from diffusing to the outside and stably maintaining discharge at a low voltage. Aim.

(5) Problems to be Solved by the Invention of Claim 5 Since gas ionization due to discharge generates a large number of ions and neutral excited species, excessive input of electric energy for discharge is caused not only by ozone but also by ozone. prompting the outbreak of nitrogen oxides NO _X which are said to adversely affect the image bearing member to nitrite, etc. to form charging and photosensitive characteristics. Therefore, in the invention of claim 5,
A major challenge is to secure the amount of charged particles necessary and sufficient for charging by optimizing the efficiency of use of electric energy, and to minimize heat and unpleasant discharge products that affect the image carrier. An object of the present invention is to provide an ion generator configured to solve the problem.

(6) Problems to be solved by the invention of claim 6 In the ion generator, ozone generated intensively in the ion generating portion is prevented from diffusing to the outside, and generation of unpleasant discharge products and reduction of power consumption, which are difficult to stably maintain the discharge at a low voltage. It is necessary for In view of the above, the invention of claim 6 provides an ion generator configured to prevent ozone generated intensively in an ion generating portion from diffusing to the outside and to stably maintain discharge at a low voltage. Aim.

(7) Problems to be solved by the invention of claim 7 In an ion generator, it is necessary to maintain a stable discharge at a low voltage in order to generate unpleasant discharge products and reduce power consumption. introduction of electric energy for discharge not only ozone, prompting outbreaks of nitrogen oxides NO _X which are said to adversely affect the image bearing member. Therefore, in the invention of claim 7, the amount of charged particles necessary and sufficient for charging is secured by optimizing the utilization efficiency of electric energy, and heat and unpleasant discharge products affecting the image carrier are minimized. Therefore, an object of the present invention is to provide an ion generator configured to solve this problem.

(8) Problems to be Solved by the Invention of Claim 8 When an ion generator is used as a charger, it is necessary to minimize the effects of heat, light, and discharge products on the image carrier. Therefore, in the invention of claim 8, charged particles (ions) necessary and sufficient for charging are secured, and discharge products are decomposed and removed at a place as far as possible from the image carrier to reduce heat radiation. It is also a major problem to prevent light accompanying the discharge from directly reaching the photosensitive member serving as the image carrier, and an object of the present invention is to provide an ion generator having a configuration that solves this problem.

(9) Problems to be Solved by Claim 9 In order to improve the utilization efficiency of electric energy required for discharging, it is necessary to transfer charged particles (ions) generated in the ion generator to the image carrier without delay and charge them. Therefore, the drift of charged particles by the electric field is necessary,
To perform this drift efficiently, extract ions,
An action to promote the ejection of ions is required. In general, a discharge current accompanying discharge occurs in a discharge power source (discharge circuit) for generating ions. In the present invention, it is measured as “drum current”). Therefore, in the invention of claim 9,
Improving the ratio of the discharge current to the drum current is an issue in reducing low power consumption and unnecessary discharge products,
An object of the present invention is to provide an ion generator configured to solve this problem.

(10) Problems to be Solved by the Invention of Claim 10 When an ion generator is used as a charger, it is necessary to minimize the effects of heat, light, and discharge products on the image carrier. Therefore, in the invention of claim 10, it is a major problem to prevent light generated by discharge from directly reaching the photoconductor, and an object of the invention is to provide an ion generator having a configuration that solves this problem.

(11) Problems to be solved by the invention of claim 11 In order to improve the utilization efficiency of electric energy required for discharging, it is necessary to transfer charged particles (ions) generated in the ion generator to the image carrier without delay and charge them. Therefore, the drift of charged particles by the electric field is necessary,
To perform this drift efficiently, extract ions,
An action to promote the ejection of ions is required. In particular, it is a problem to expel ions quickly in a portion near the image carrier. On the other hand, residence prone ozone fine discharge space, discharge products such as NO _X is because it decomposed and removed by the catalyst, reducing the discharge products to cause catalytic activated by discharge light in the discharge space Important above. Therefore, an object of the present invention is to provide an ion generator having a configuration that solves the above-mentioned problem.

(12) Problems to be Solved by the Invention of Claim 12 The input energy for discharge becomes larger as the discharge space becomes larger, and unnecessary and unpleasant discharge products are generated. When the discharge space is large and the system is open, the discharge products are diffused. As a countermeasure for the above, it is necessary to separate and miniaturize the discharge space. Further, when the ion generator is used as a charging device, the ion generator is often mounted on an electrophotographic image forming apparatus such as a copying machine or a printer. Therefore, in the invention of claim 12, the problem is to form an array in which a large number of simple shapes are integrated in order to make the discharge space finer, and an object of the present invention is to provide an ion generator having a configuration that solves this problem. I do.

(13) A problem to be solved by the invention of claim 13. The invention of claim 13 has the same problem as the above (12). In particular, since a photoreceptor is frequently used as an image carrier to be charged, it is necessary to eliminate the influence of heat and light. This is a major problem in the structure of the charging device. Therefore, claim 1
An object of the third invention is to provide an ion generator configured to solve the above-mentioned problem.

(14) Problems to be Solved by Claim 14 When an ion generator is used as a charging device, the ion generator is often mounted on an electrophotographic image forming apparatus, and the document size varies depending on the model. Therefore, it is inconvenient to design and manufacture the charging device unit according to the document size one by one. In addition, if a part of the charging device should be damaged by sparks, etc., if the function can be restored by replacing only the failed unit, the running cost of equipment can be reduced. There is a strong tendency to require equipment. Therefore, an object of the present invention is to provide an ion generator having a configuration that solves the above-mentioned problems.

(15) Problems to be Solved by the Inventions of Claims 15, 16, and 17 Electrophotographic image forming apparatuses such as copiers, printers, and facsimile machines are required to be environmentally friendly in addition to being inexpensive, multifunctional, and are subject to virtually global regulations such as ozone emission regulations. Therefore, with the increasing tradeoff that ozone is not emitted without impairing the performance of the charging device, it is desired to supply a charging device that is low in cost and does not pollute the environment. On the other hand, high performance is desired for the above-described image forming apparatus, and one of the requirements is high-speed recording. For high-speed recording, the charging speed must be high. The roller charger found in the prior art has a small amount of discharge products such as ozone, but performs a charging action by contact with an image carrier and is not suitable for high speed operation. Therefore, it is necessary to satisfy minimization of discharge products in a non-contact state and high-speed recording. In order to solve the above-mentioned problems, the present invention provides a charging method and a charging device that can minimize discharge products in a non-contact state and can perform high-speed charging. With the goal. The invention of claim 17, wherein the foregoing problems, and reduce the occurrence of discharge products such as ozone and NO _X, UL standards, T
It is an object of the present invention to provide an image forming apparatus that satisfies the standards such as the UV standard and the BAM standard and enables high-speed recording.

[0024]

As means for solving the above-mentioned problems, the invention according to claim 1 is to dispose a dielectric between conductor electrodes and form a substantially closed space sandwiched between them. An ion generator comprising an electrode structure having a fine discharge space, and applying an AC voltage between the conductor electrodes to generate charged particles by discharge, wherein the dielectric is a dielectric tangent of a high-frequency dielectric characteristic. The value is 30 × 10 ⁻⁴ or more.

According to a second aspect of the present invention, there is provided an electrode structure having a fine discharge space which forms a substantially closed space between the conductor electrodes by disposing a dielectric between the conductor electrodes. An ion generator for generating charged particles by discharging by applying an AC voltage, characterized in that the ion generator is composed of an element composed of a member having a large dielectric tangent and an element composed of a member having a small dielectric tangent. And

According to a third aspect of the present invention, there is provided a semiconductor device comprising:
An electric body is arranged, and a fine
An electrode structure having a discharge space between the conductive electrodes.
An AC voltage is applied to generate charged particles by discharging.
An on-generator, wherein the value of the dielectric loss tangent of the dielectric is 3
0x10^-FourElements composed of the above members and 10 × 10 ^-Four
It is characterized that it consists of two types of elements composed of the above members.
Sign.

According to a fourth aspect of the present invention, in the ion generator of the first aspect, a gap of the discharge space formed by the conductor electrode and the dielectric is 280 μm to 390 μm. The invention according to claim 5 is
2. The ion generator according to claim 1, wherein the frequency of the applied AC voltage is between 2.0 kHz and 5.0 kHz, and the leading value of the AC voltage is between 2.5 kV and 5.0 kHz.
kV.

According to a sixth aspect of the present invention, in the ion generator of the third aspect, the gap of the discharge space formed by the conductor electrode and the dielectric is 280 μm to 390 μm. The invention according to claim 7 is
4. The ion generator according to claim 3, wherein the frequency of the applied AC voltage is between 2.0 kHz and 5.0 kHz, and the head value of the AC voltage is between 2.5 kV and 5.0 kHz.
kV.

The invention according to claim 8 is the invention according to claim 2 or 3.
The ion generator described above is characterized in that an element composed of a member having a large dielectric tangent generates ions by silent discharge, and an element composed of a member having a small dielectric tangent generates ions by creeping discharge. According to a ninth aspect of the present invention, in the ion generator according to the second or third aspect, an element formed of a member having a large dielectric tangent and an element formed of a member having a small dielectric tangent are provided.
A first ion extraction electrode is provided, and a second ion extraction electrode is provided inside an element made of a member having a small dielectric loss tangent. According to a tenth aspect of the present invention, in the ion generator according to the second or third aspect, a shield plate for shielding discharge light is provided between the element made of a member having a small dielectric loss tangent and the member to be charged. It is characterized by the following. Still further, according to an eleventh aspect of the present invention, in the ion generator according to the second or third aspect, the second ion extraction electrode disposed inside the element made of a member having a small dielectric loss tangent is higher than the surrounding discharge space. Is maintained at a negative potential, and the surface of the ion extraction electrode contains a photocatalytic substance.

According to a twelfth aspect of the present invention, in the ion generator of the first aspect, the electrode structure includes a conductor electrode having a coaxial cylindrical shape and a dielectric member. Are arranged. According to a thirteenth aspect of the present invention, in the ion generator according to the second or third aspect, the element made of a member having a large dielectric loss tangent is formed of a conductor electrode having a coaxial cylindrical shape and a dielectric member, or is formed in parallel. It is characterized by comprising a conductor electrode having a flat plate shape and a dielectric member, and the element comprising a member having a small dielectric loss tangent is constituted by a conductor electrode having a parallel plate shape and a dielectric member. According to a fourteenth aspect of the present invention, in the ion generator according to the twelfth or thirteenth aspect, a unit in which a plurality of elements constituted by a conductor electrode having a coaxial cylindrical shape and a dielectric member are arranged as a unit, or A unit composed of a pair of opposing parallel-plate-shaped conductor electrodes and a dielectric member is used as a unit, and each unit has a structure that can be brought into contact with and separated from the unit. It can be set to.

According to a fifteenth aspect of the present invention, there is provided a charging method for charging an object to be charged, wherein the ion generator according to any one of the first to fourteenth aspects is used. The charged object is charged by the charged particles. The invention according to claim 16 is
A charging device for charging an object to be charged, comprising the ion generator according to any one of claims 1 to 14, wherein the object to be charged is charged by charged particles generated by the ion generator. It is characterized by.

According to a seventeenth aspect of the present invention, there is provided an image carrier which is an object to be charged, forms a latent image on the image carrier, develops the latent image into a visible image, In an image forming apparatus that forms an image by transferring a visible image on a carrier to a transfer material,
15. As a means for charging an image carrier which is an object to be charged, a means for transferring a visible image on the image carrier to a transfer material, or a means for discharging the image carrier, any one of claims 1 to 14. An ion generator according to one aspect, a charging method according to claim 15, or a charging device according to claim 16 is mounted.

Here, the ion generator according to the present invention, the charging method using the ion generator, and the principle of the charging device will be described. Generating charged particles (ions) by generating gas ionization by discharging is an efficient and advantageous means for charging an image carrier (for example, a photoconductor) as a member to be charged. A representative example is corona discharge. However, in a corona charger that generates a corona discharge by applying a high voltage between a thin metal wire (for example, a tungsten wire) and a shield electrode, the discharge space is large and ions are formed in the vicinity of the wire. Ozone is produced in large quantities. On the other hand, in the ion generator of the present invention and the charging device using the ion generator, the discharge product is confined in a fine discharge space composed of a conductor electrode and a dielectric, and ozone is decomposed in the discharge heat space. It is characterized by

In general, the theory of ozone generation by electric discharge explains that the rate of thermal decomposition of ozone is inversely proportional to the oxygen concentration under excess oxygen, and that the ozone concentration has a quadratic relationship. The above description is about ozone generation by oxygen raw materials, for example, "Plasma Material Chemistry Handbook" (edited by Japan Society for the Promotion of Science, Plasma Material Science 153 Committee, Ohmsha, published in 1992), Chapter III, Chapter 1, P .
274-277 ". The present inventors presume that ozone generation from air raw materials has a similar effect,
I made the following hypothesis.

FIG. 7 shows an equation based on the reaction rate equation for the generation and decomposition of ozone. FIG. 7 is an explanatory diagram of the rate of generation / decomposition of ozone in a thermal space and the rate of decomposition reaction. The equation shown in FIG. 7: −dC / dt = K · C ² indicates that the ozone decomposition rate is remarkably accelerated in a system having a relatively high ozone concentration in a fine space.

On the other hand, in the present invention, gas ionization is performed in air, and it is inferred that the pressure is high as in the atmospheric pressure, and that molecules tend to stay in a fine space. This is described, for example, in “Physics and Application of Vacuum” (Hirio Kumagai et al., Shokabo, published in 1977), p. 93 to 94 ". This can be briefly summarized as follows. For the sake of clarity, a fine inner diameter such as a capillary tube shown in FIG. Taking a cylindrical tube having L) as a model, the “gas flow in the model thin tube” is as follows. At high pressures, the gas mass is considered a continuum and becomes viscous. From the gas molecule kinetic theory, the viscosity coefficient η is represented by the following equation without depending on the pressure. η = 0.499ρυλ ρ: density of gas υ: average velocity of gas molecules Therefore, the flow rate Q of gas flowing through the model capillary shown in FIG. 8 is given as follows. Q = (π / 8ηL) a ⁴ · ((P ₁ + P ₂ ) / 2) (P ₁ −P ₂ ) Under the atmospheric pressure, the gas flow in the tube is small because P ₁ ≒ P _{2 in the} thin tube. Therefore, Q can be made very small by reducing the radius a of the pipe and increasing the length L of the pipe (Q → 0: turbulent flow). As described above, stagnation of gas molecules such as ozone is likely to occur in a gas under atmospheric pressure by miniaturizing the space. When an ion generator having a discharge space such as the above-mentioned model capillary is used as a charging device, an electric field is applied to the discharge space to transfer charged particles. Therefore, ions easily drift, and neutral particles such as ozone tend to stay in the discharge space. That is, discharge products such as ozone can be confined in the discharge space. The above can be conceptually explained as shown in FIG.

The present invention has the following features as a result of intensive studies. (1) In the present invention, an AC (high frequency) silent discharge is performed by applying an AC voltage by using a space having a small gap in an electrode structure formed of a cylindrical or parallel plate formed of a conductor electrode and a dielectric member as a discharge space. By utilizing alternating current (high frequency) surface discharge, the action of removing the discharge products is realized by promoting the ozonolysis reaction and retaining the neutral molecules as described above. (2) In the present invention, a dielectric member having a large dielectric loss tangent: tan δ is used for one of the electrode structures of the above (1), a part of the discharge energy is stored in the electrode member as heat energy, and the discharge space is decomposed with ozone. The optimal heat space to promote the ozone decomposition is realized. In the present invention, since the discharge space is fine, charged particles required for charging are generated without consuming extra energy input to the space. (3) In the present invention, a dielectric member having a small dielectric loss tangent: tan δ is used for one of the electrode structures of the above (1), an induction electrode is provided inside the dielectric, and a linear (stripe) is provided on the surface. By providing the discharge electrode of the above, it is possible to generate a discharge on the surface of the discharge electrode without excessive heat generation of the electrode member and to secure an amount of ions necessary for charging.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction, operation and operation of the present invention will be described below in detail with reference to the illustrated embodiments.

[Embodiment 1] First, claims 1, 15, 1
The configuration and operation of the invention according to No. 6 will be described. FIG. 1 is an explanatory diagram of the configuration and operation when the ion generator according to the present invention is used as a charging device. As shown in a partially enlarged manner in FIG. 1, the coaxial cylindrical discharge electrode constituting the ion generator of the element 1 is formed by forming a thin center electrode 6 with a minute gap in a dielectric cylinder (insulating cylinder) 8. It is a configuration that is arranged,
The gap portion serves as a discharge space. An external induction electrode 7 is arranged on the outer periphery of the dielectric cylinder 8. In the coaxial cylindrical discharge electrode having such a configuration, an AC power supply 11 is connected between the center electrode 6 and the external induction electrode 7 as shown in FIG. When an AC voltage is applied between the electrodes 7 to generate a discharge, a silent discharge by an AC is generated in a gap in the discharge electrode. In the example of FIG. 1, an image carrier (eg, a photosensitive drum) 17, which is a member to be charged, is charged.
DC voltages from bias power supplies 12 and 13 are applied to a common electrode 9 which is a common electrode of the center electrode 6 and a common electrode 10 which is a common electrode of the external induction electrode 7, respectively. A member having a large dielectric loss tangent is used for the dielectric cylinder 8 of the coaxial cylindrical discharge electrode. Dielectric loss occurs due to the input of AC high-frequency electric energy, and heat is generated. It does not happen until the member is damaged.

FIG. 1 shows a representative embodiment of a charging device using an ion generator according to the present invention. The center electrode 6 has a diameter of 6
It is a metal wire of 5 μm, and a tungsten wire or a stainless wire is used. The dielectric cylinder 8 has a dielectric tangent (tan δ) value, which is one of the dielectric characteristics in the MHz band, approximately 110 × 1.
0 ^-4 cylindrical soda glass which is (1 MHz), an inner diameter of 0.85 mm, an outer diameter is 1.65 mm. Another dielectric material is a dielectric loss tangent (tanδ) at 1 MHz.
Aluminoborosilicate glass having a value of about 100 × 10 ⁻⁴ , low expansion borosilicate glass having a value of about 46 × 10 ⁻⁴ , and aluminosilicate glass having a value of about 37 × 10 ⁻⁴ can also be used.

The external induction electrode 7 is provided in close contact with the outer periphery of the dielectric cylinder 8, and is formed, for example, of a metal thin film with a thickness of several μm to several tens μm by means of vacuum deposition, sputtering, plating or the like. In addition, a metal vapor-deposited tape or the like may be simply adhered so that no void is formed on the outer periphery of the dielectric cylinder 8. Using the above-described coaxial cylindrical discharge electrode as a unit, 25 pieces of the same electrode were arranged over a width of 50 mm to form an ion generator as shown in "Element 1" in FIG. A common electrode 9 serving as a common electrode is provided on the insulating substrate 5 holding each center electrode 6.
Is connected to Similarly, a dielectric cylinder 8 having an external induction electrode 7 attached to the outer periphery is also arranged on another insulating substrate 5, and a common electrode 10 provided on the insulating substrate 5 is connected to each external induction electrode 7. . Since the ion generator of the “element 1” performs a charging action on the image carrier 17, a negative potential (about −1.5 kV) is applied by the bias power supplies 12 and 13.
Biased. An AC power supply 11 is provided between the center electrode 6 and the external induction electrode 7 of the coaxial cylindrical discharge electrode, and an AC high frequency voltage (maximum voltage 6 kV) having a frequency of several kHz is applied. The mesh-like first ion extraction electrode 15 held by the insulating support 14 is
It has a role of extracting negatively charged ions among charged particles generated in the coaxial cylindrical discharge electrode to the outside of the cylinder. The power supply indicated by reference numeral 16 is an ion extraction power supply for this purpose, which is positively high when viewed from the coaxial cylindrical discharge electrode and is set to a negative potential (about -0.8 kV) when viewed from the ground.

The photosensitive drum serving as the image carrier 17 can be charged by the ion generator of the "element 1". In the present invention, it is necessary to obtain the characteristics of the ion generator. In order to measure the ion current as an ion current, a current obtained by placing a conductor such as an aluminum drum at the position of the image carrier 17 (hereinafter referred to as a drum current) Was evaluated using the drum current measuring device 18. The charging potential of the image carrier 17 was evaluated using a dielectric film having a dielectric constant close to that of the photoconductor and using a surface voltmeter.

Next, FIG. 2 is a view showing another embodiment of the coaxial cylindrical discharge electrode constituting the ion generator according to the first aspect. In the present invention, the coaxial cylindrical discharge electrode having the configuration shown in FIG. 1 is called a coaxial type A, and the coaxial cylindrical discharge electrode having the configuration shown in the embodiment of FIG. In FIG. 2, reference numeral 6 denotes a center electrode made of a metal wire and has a diameter of 65 mm.
μm. On the outer periphery of the center electrode 6, a thin film 19 of a dielectric material is formed over the entire surface including the top.
The dielectric thin film 19 has a dielectric loss tangent (tan δ), which is one of the dielectric properties, depending on the frequency, but is approximately 50 to 2.
Barium titanate (BaTiO ₃ ) exhibiting 50 × 10 ^-4
Is a film having a thickness of 8 μm. An existing method such as a sol-gel method is used for forming the dielectric thin film 19. The center electrode 6 on which the dielectric thin film 19 is formed outside has an inner diameter of 0.1 mm.
It is arranged with a slight gap 21 in a metal cylinder (external induction electrode) 20 of 85 mm and having an outer diameter of 1.65 mm. The configuration of the ion generator is such that the coaxial cylindrical discharge electrode of FIG. 2 is arranged in the same manner as in FIG. 1, and the operation is also the same as that shown in FIG.

Next, FIG. 3 shows another embodiment of the ion generator according to the first aspect, and is a structural explanatory view showing an example of an ion generator comprising parallel plate type discharge electrodes. FIG.
In (a), three metal conductor electrodes 23 made of a conductor electrode plate having a thickness of 0.5 mm are inserted and fixed at a predetermined interval in an insulating member 22 except for a metal conductor electrode at the center. The surface of the metal conductor electrode on both sides has a dielectric tangent (ta
A vitreous dielectric member 24 whose value of nδ) is approximately 110 × 10 ⁻⁴ (1 MHz) is fused. The gap width between the center metal conductor electrode and each dielectric member 24 is approximately 0.3 mm. The insulating member 22 has a metal conductor electrode 2
3, a conductive electrode 25 for connecting a power source is provided. Between the central metal conductor electrode and the metal conductor electrodes including the dielectric members on both sides thereof, an alternating current (not shown) is provided in the same manner as in the method shown in FIG. A power supply and a DC bias power supply are connected, and an AC high frequency voltage and a bias voltage are applied. In this case, a high-frequency silent discharge occurs in a gap (discharge space) between the central metal conductor electrode and the metal conductor electrodes on both sides to generate ions.
These ions are extracted to the outside using an ion extraction electrode as in the method shown in FIG. In addition, FIG.
The ion flow drawn from this ion generator is shown schematically.

[Embodiment 2] Next, claim 2, 15, 16
The configuration and operation of the invention according to the above will be described. FIG. 4 is an explanatory diagram of the configuration and operation when the ion generator according to the present invention is used as a charging device. In this example, the ion generators 1 and 2 of the element 1 and the element 2 in which two kinds of dielectric members having different values of dielectric loss tangent are included in the electrodes are arranged in series. In this configuration example, a discharge is generated in the ion generator 1 of “element 1”, and the ions are used as charged particles for charging. The generation of ozone is suppressed by using a means that promotes the decomposition of ozone in the fine discharge heat space, and at the same time, the first ion extraction electrode 2 attached to the ion generator 1 of the “element 1” is effective in charging. Draw out negative ions. Further, in the ion generator 3 of “element 2”, heat radiated from the heat space of the ion generator 1 of “element 1” is prevented from reaching the image carrier (for example, the photosensitive drum) 4 and “ion 2” The ion generator 3 generates ions having a negative charge used for charging. Note that a dielectric having a small dielectric loss tangent is used for the electrode member of the ion generator 3 of the “element 2”, and the heat generated when the discharge energy is input is small.

(Embodiments according to the second, fifteenth, and sixteenth aspects) The ion generator 1 of the "element 1" is made of a dielectric member having a large dielectric loss tangent. This "element 1" ion generator 1
Has a member and a structure shown in the embodiment of the above-mentioned claim 1 (one of FIGS. 1 to 3). "Element 2" ion generator 3
As shown in the structural explanatory view of FIG. 5, is composed of two discharge electrodes 26, an insulating support 31, a side wall 32, a light shielding plate 33, a second ion extraction electrode 34, and the like.
As shown in FIG. 5A, the discharge electrode 26 is made of a 1 mm-thick tungsten material inside a dielectric member 27 made of fused quartz, alumina ceramic, or the like having a small dielectric loss tangent (tan δ). It comprises an induction electrode having a structure in which an embedded electrode 28 is provided, and a linear electrode 29 formed on a surface of a dielectric member 27 using a metal such as copper. The embedded electrode 28 of the discharge electrode 26 and the linear electrode 2
The distance of 9 is about 0.9 mm. The linear electrode 29 has a width of 1.
5 mm and a thickness of 80 μm. The distance between adjacent linear electrodes is approximately 300 μm, and is formed by a method such as plating. A second ion extraction electrode 34 is disposed at the center of the insulating support 31, and two discharge electrodes 26 each having the embedded electrode 28 and the linear electrode 29 disposed at a symmetrical position with respect to the second ion extraction electrode 34. Are placed. The second ion extraction electrode 34 is a 0.3 mm thick stainless steel mesh. The gap between the second ion extraction electrode 34 made of the stainless mesh and the linear electrodes 29 of the two discharge electrodes 26 is 0.3 mm.
In accordance with this gap, for example, a parallel plate-shaped discharge electrode constituting the ion generator of "element 1" shown in FIG. 3 is installed, but when a coaxial cylindrical discharge electrode as shown in FIG. 1 is used. Are arranged such that the ion flow from the ion generator of "element 1" reaches the gap of FIG. Therefore, two sets of coaxial cylindrical discharge electrodes arranged in a line are used. An AC voltage having a maximum of 6 kV (Vp-p) and a frequency of several kHz is applied by an AC power supply 30 between the embedded electrode 28 and the linear electrode 29 of the discharge electrode 26. Insulation support 3
1 is surrounded by a side wall 32 and a light-shielding plate 33, and the light-shielding plate 33 has an opening 3 through which an ion flow is radiated to the outside.
3a. In addition, the second ion extraction electrode 34
The potential is set to be positively higher than that of the first extraction electrode 2 shown in FIG.

[Third Embodiment] Next, a third embodiment will be described.
The configuration and operation of the invention according to the above will be described. In the charging device of the present embodiment, a coaxial cylindrical discharge electrode having the configuration shown in FIG. 1 or FIG. 2 or a parallel flat plate discharge electrode having the configuration shown in FIG. 3 was used as the ion generator of “element 1”. It has a large value as a dielectric loss tangent of a dielectric member constituting a discharge electrode, so that a dielectric loss occurs in a high-frequency discharge in a kHz frequency band, and a fine discharge space is made a heat space advantageous for ozone decomposition. At the same time, negative ions used for charging are released to the outside. In the latter part of the ion generator of "element 1" (closer to the image carrier), "element 2" of the structure shown in FIG. 5 having a discharge electrode using a dielectric member having a small value as a dielectric loss tangent is provided. ), Radiation heat from the discharge electrode due to dielectric loss is suppressed, and deterioration of the physical characteristics of the photoconductor as an image carrier is eliminated.
Further, since the charging operation is performed using the ion currents from both ion generators, it is possible to cope with a case where a high charging speed is required.

(Embodiments according to Claims 3, 15, and 16) In the coaxial cylindrical discharge electrode of the ion generator having the structure shown in FIG. 1, a dielectric is provided outside the center electrode 6 made of a metal wire having a diameter of 65 μm. The body cylinder 8 is arranged. The dielectric cylinder 8 having an inner diameter of 0.85 mm and an outer diameter of 1.65 mm is a soda glass having a dielectric loss tangent (tan δ) of 1 × 10 MHz, which is one of the dielectric properties, of about 110 × 10 ^−4. For example, aluminoborosilicate glass of about 100 × 10 ⁻⁴ , low expansion borosilicate glass of about 46 × 10 ⁻⁴ , aluminosilicate glass of about 37 × 10 ⁻⁴ and the like are used. In addition, materials such as soft mica, rubber-based dielectric materials, and porcelain ceramics having large values of dielectric loss tangent are not preferable because of poor heat resistance and workability as an electrode member. In the coaxial cylindrical discharge electrode having the configuration shown in FIG. 2, the metal center electrode 6 is coated with a dielectric thin film 19. As a coating material, a glass member such as a barium titanate thin film or soda glass having a large value of dielectric loss tangent (tan δ) in a 1 MHz band of 50 to 200 × 10 ^-4 is coated with a thickness of several μm to 20 μm. Use what was done. As described above, the ion generator using the dielectric member having a dielectric loss tangent of 30 × 10 ⁻⁴ or more at the high frequency in the MHz band as the electrode member is used as the element 1. Further, in the subsequent stage of the ion generator of "element 1" (closer to the image carrier), as shown in FIG. 5, fused quartz whose dielectric loss tangent in the MHz high-frequency band is approximately 5 × 10 ^-4. Electrode 2 for guiding in dielectric member 27 of aluminum or alumina
8, a discharge electrode having a configuration in which a large number of linear electrodes 29 are arranged on the surface of the dielectric member 27 with a gap therebetween is used. The discharge electrode having the configuration shown in FIG.
An ion generator using a dielectric member having a dielectric loss tangent of ⁻⁴ or less as an electrode material is configured, and this ion generator is used as the element 2.

[Fourth Embodiment] Next, a fourth aspect of the present invention will be described.
The configuration and operation of the invention according to the above will be described. In the ion generator of the present embodiment, as in the configuration shown in FIG. 1, a space is provided between the center electrode 6 and the external induction electrode 7 serving as an induction electrode to form a discharge space, and a dielectric cylinder 8 is disposed therebetween. are doing. Then, an AC voltage is applied between the center electrode 6 and the external induction electrode 7 to generate a discharge. 2 is an example in which the center electrode 6 is covered with a dielectric thin film 19 without using a dielectric cylinder. Further, the configuration shown in FIG. 3 uses a flat electrode 23 and a dielectric member 24 without using a cylindrical discharge electrode. In each case, a high-frequency silent discharge is generated in a slight gap by applying an AC voltage. It is in a shape suitable for letting it go.

(Embodiments of the Inventions of Claims 4, 15, and 16) The ion generator of this embodiment has the structure shown in FIG. 1, FIG. 2, or FIG. This is the same as that described in (Embodiments of the first, fifteenth, and sixteenth aspects) of [Embodiment 1]. In the coaxial cylindrical discharge electrode having the configuration shown in FIG. 1, the outer diameter of the center electrode 6 is 65 μm and the inner diameter of the dielectric cylinder (insulating cylinder) 8 is 850 μm.
Therefore, the gap between them was approximately 390 μm.
In the case of the electrode structure of FIG. 1, the outer diameter of the center electrode 6 is 3
Discharge generation was possible between 0 μm and 350 μm, that is, when the gap length of the air gap was between 410 μm and 250 μm, but it was stable under the conditions of an AC high frequency of 1 kHz to 5 kHz and a maximum applied voltage of 5 kV (Vp-p) or less. In order to obtain a good discharge, the gap length of the air gap should be 280 μm to 390 μm.
It is desirable to set it to μm. On the other hand, in the case of the coaxial cylindrical discharge electrode structure shown in FIG. 2, the surface of the center electrode 6 having an outer diameter of 65 μm is covered with a dielectric film 19 to a thickness of about 8 μm so as to maintain a gap between the electrode and the external electrode 20. A voltage application method similar to that of FIG. 1 is applied. In this case as well, a discharge could be generated under the same power supply conditions as described above with a gap length of the air gap between 240 μm and 400 μm, but the stable discharge continued for 280 μm.
It was possible between m and 390 μm. Further, in the case of the parallel plate type discharge electrode structure having the configuration shown in FIG.
A soda-glassy dielectric is fused to a surface of a 5 mm metal conductor electrode 23 with a thickness of 0.3 mm. In this case, the gap gap length with the metal conductor electrode at the center is 2
Although discharge generation was possible between 00 μm and 400 μm, small sparks frequently occurred when the gap length was small, and stable discharge could be sustained when the gap length was approximately 270 μm to 400 μm.

[Embodiment 5] Next, claims 5, 15, and 16 will be described.
The configuration and operation of the invention according to the above will be described. In the ion generator of the present embodiment, as in the configuration shown in FIG. 1, a space is provided between the center electrode 6 and the external induction electrode 7 serving as an induction electrode to form a discharge space, and a dielectric cylinder 8 is disposed therebetween. are doing. Then, an AC voltage is applied between the center electrode 6 and the external induction electrode 7 to generate a discharge. In the configuration of FIG. 2, the center electrode 6 is covered with a dielectric film 19 without using a dielectric cylinder. Further, the configuration shown in FIG. 3 uses a flat metal conductor electrode 23 and a dielectric member 24 without using a coaxial cylindrical discharge electrode. In each case, a high-frequency silent discharge is slightly reduced by applying an AC voltage. The shape is suitable for generating in the void.

(Embodiments of the Inventions of Claims 5, 15, and 16) This embodiment has the structure shown in FIG. 1, FIG. 2, or FIG. 3, and the materials and dimensions of the components are [Embodiment 1]. (Embodiments according to the first, fifteenth, and sixteenth aspects of the invention). In the present embodiment, a high-frequency silent discharge can be generated in the electrode structure having the configuration shown in FIG. 1, FIG. 2, or FIG. it can. In general, as the frequency of the high frequency is higher, the input energy is more efficiently injected into the discharge space, the discharge efficiency is increased, and the discharge current is increased. The current flowing in the discharge system is referred to as a current, and the current flowing in the discharge system is referred to as a collector current or a drum current. However, since the frequency of the AC voltage applied between the electrodes of the discharge electrodes is increased unnecessarily large and the generation of ozone, also tends to increase rapidly the generation of nitrogen oxides more to (NO _X), charging The frequency that is necessary and sufficient for the operation and that the electrode member can withstand heat generation is 2 kHz.
To 5 kHz is most desirable. Also, with the configuration of the first aspect of the present invention, it is possible to obtain a discharge current from 1 kV for the value of the leading value Vp-p of the AC voltage. However, the power consumption is large and the power supply capacity and shape must be large. In addition, a value of Vp-p from 2.5 kV to 5 kV was appropriate for stable discharge without abnormal discharge.

[Embodiment 6] Next, claims 6, 15, and 16 will be described.
The configuration, operation and embodiment of the invention according to the present invention will be described. The configuration and operation of the “element 1” ion generator 1 made of a member having a large value of the dielectric loss tangent are as described in the above [Embodiment 1]. Further, the gap of the discharge space of the ion generator of “Element 1” is stable between 280 μm and 390 μm as shown in (Embodiment 4). Discharge was sustained. As shown in FIG. 5, the configuration of the ion generator 3 of the "element 2" made of a member having a small dielectric tangent value is such that the thickness of the ion generator 3 is small inside a dielectric member 27 of fused quartz or alumina ceramic having a small dielectric tangent value. An embedded electrode 28 of 1 mm in tungsten material is provided to form an induction electrode. On the surface of the dielectric member 27, a linear electrode 29 using a metal such as copper is formed to form a discharge electrode. The distance between the embedded electrode 28 and the linear electrode 29 is about 0.9 mm. Linear electrode 29
Has a width of 1.5 mm and a thickness of 80 μm, the distance between adjacent linear electrodes is approximately 300 μm, and is formed by a method such as plating. Embedded electrode 28 and linear electrode 2
During the period 9, an AC voltage having a maximum of 6 kV (Vp-p) and a frequency of several kHz is applied by the AC power supply 30. With the above configuration, the distance between the linear electrodes is set to 250 μm, 280 μm, 300 μm.
When the characteristics of discharge generation were examined by changing to μm, 350 μm, and 400 μm, discharge breakdown frequently occurred at intervals of 250 μm. At 400 μm, discharge stopped, but at 390 μm, stable discharge was performed. did it. The discharge extended from the end of the linear electrode along the surface of the electrode.

[Embodiment 7] Next, a seventh embodiment will be described.
The configuration, operation and embodiment of the invention according to the present invention will be described. The configuration and operation of the “element 1” ion generator 1 made of a member having a large value of the dielectric loss tangent are as described in the above [Embodiment 1]. Further, the power supply condition when the ion generator of “Element 1” performs the charging operation is, as shown in (Embodiment 5 according to the fifth, fifteenth, and sixteenth inventions), a frequency. 2kHz to 5kHz,
It is desirable to generate a discharge at a voltage of Vp-p from 2.5 kV to 5 kV. The configuration of the ion generator of “element 2” made of a member having a small dielectric loss tangent is as shown in FIG. 5, and the description is as described in the above [Embodiment 6]. And the AC frequency is 1k
When the frequency was changed from Hz to 6 kHz, discharge products such as ozone greatly increased at 6 kHz. Also, 1 kHz
At the frequency of z, the form of discharge along the linear electrode could not be confirmed. At 2 kHz, a sufficient ion current for charging could not be secured by discharging.

[Embodiment 8] Next, claims 8, 15, and 16 will be described.
The configuration, operation and embodiment of the invention according to the present invention will be described. As shown in FIG. 4, the value of the dielectric loss tangent is 30 × 10
"Element 1" ion generator 1 with ^-4 or more dielectric members
And the entire ion generator consisting of two elements of the "element 2" ion generator 3 having a dielectric member having a dielectric loss tangent of 10 × 10 ⁻⁴ or less was used as the charging device. The configuration and operation example of the ion generator 1 is described in [Embodiment 4].
This is the same as the configuration and operation described in (Embodiments 5 and 16). When the discharge electrode including the dielectric member has a gap gap length of 280 μm to 390 μm and an AC voltage of Vp-p from 2.5 kV to 5 kV under a condition of a frequency of 2 kHz to 5 kHz, the entire gap within the minute gap is applied. Discharge was confirmed, high-frequency silent discharge occurred, and generation of ozone was confirmed by an ozone densitometer. However, compared to a normal ozonizer for the purpose of mass production of ozone, the discharge gap is small, and in addition, the ozone thermal dissociation reaction proceeds,
The detection amount was 0.09 ppm or less, which was extremely small.
During the discharge, the temperature was measured at a position 3 mm below the center of the ion generator 1, and as a result, it was found to be about 96 ° C.

The configuration and operation example of the ion generator 3 of “element 2” are as described in Examples such as [Embodiment 6]. The distance between the linear electrodes of the discharge electrode 26 is 280 μm to 390 μm, and the AC voltage is 2.5 kV or more and 5 kV.
When Vp-p was applied under conditions of a frequency of 2 kHz to 5 kHz, thin discharge light was observed on the dielectric surface along the linear electrodes. In this case, no discharge was confirmed at the center of the ion generator 3 but concentrated on the electrode surface including the dielectric, and a creeping discharge was confirmed. The temperature was measured at a position 3 mm below the center of the ion generator 3, and as a result, the temperature was about 58 ° C. This is because the temperature in the discharge space is "element 1"
It is considerably lower than that of the ion generator 1 of FIG.

[Embodiment 9] Next, the ninth, fifteenth and sixteenth aspects will be described.
The configuration, operation and embodiment of the invention according to the present invention will be described. In the present embodiment, as shown in FIG. 4, an ion generator 1 of "element 1" having a dielectric member having a large dielectric loss tangent;
The entire ion generator including the two elements of the "element 2" ion generator 3 having a dielectric member having a small dielectric loss tangent was used as a charging device. As shown in FIG. 4, the ion generator 1 of “element 1” having a dielectric member having a dielectric loss tangent of 30 × 10 ⁻⁴ or more has a first ion made of a 0.5 mm thick stainless steel mesh. An extraction electrode 2 is provided, and the first ion extraction electrode 2 has a configuration similar to the first ion extraction electrode 15 of the ion generator of “element 1” shown in FIG. A voltage of, for example, -0.8 kV, which is a negative potential from the ground, is applied by the ion extraction power supply 16 so that the potential of the first ion extraction electrode 15 becomes a positive potential when viewed from the ion generator 1. When the length of the ion generator 1 is set to 50 mm and the discharge current of the ion generator 1 is 550 μA, if the first ion extraction electrode 15 is not provided, the ion generator 1 flows into an aluminum drum 10 mm away. The drum current is 1.
Although it was about 5 μA, the first ion extraction electrode 15
In the case of the addition, the drum current of 8.5 μA could be secured with the same ion generator having a width of 50 mm. On the other hand, the ion generator 3 of “element 2” composed of a member having a small dielectric loss tangent
Is similar to the configuration described in the example of [Embodiment 2] as shown in FIG. 5, and the second ion extraction electrode 34 of this ion generator is a stainless mesh having a thickness of 0.3 mm. is there. This second ion extraction electrode 3
The potential applied to 4 is positively high when viewed from the bias potential of the ion generators 1 and 3, and is maintained at, for example, -0.55 kV as a substantially negative potential with respect to the ground. The second ion extracting electrode 34 extracts a negative ion current coming out of the ion generator 1 in the direction of the ion generator 3 and also drives a negative ion generated by discharge in the ion generator 3 to the outside of the repeller. Plays a role.

The “element 1” ion generator 1 having the above configuration
And the ion generator 3 of the "element 2" is arranged with respect to the image carrier 4 as shown in FIG. 4 to constitute a charging device having a width of 50 mm. The drum current flowing through the aluminum drum was examined. When the discharge current of the ion generator 1 was 550 μA and the first ion extraction electrode 15 was operated, the current flowing into the aluminum drum 10 mm away from the center of the ion generator 3 was examined. When the discharge current of the ion generator 3 was 320 μA, the drum current was 2.2 μA. This value is when the second ion extraction electrode 34 is not provided. When the above-mentioned potential was applied by attaching the second ion extraction electrode 34, the drum current was 11.7 μA.

[Tenth Embodiment] Next, the tenth, fifteenth,
The configuration and operation of the invention according to the sixteenth embodiment and an embodiment will be described. In the present embodiment, as shown in FIG. 4, the ion generator 1 of "element 1" having a dielectric member having a large dielectric loss tangent is used.
The entire ion generator including the ion generator 3 of "element 2" having a dielectric member having a small dielectric loss tangent was used as a charging device. The configuration and operation of the “element 1” ion generator 1 made of a member having a large value of the dielectric loss tangent are as described in the above [Embodiment 1]. “Ion generator 2” ion generator 3 made of a member having a small dielectric loss tangent
Is similar to the configuration described in the example of [Embodiment 2] as shown in FIG. 5, and in FIG. 5, the elements of the discharge electrode are side walls 32 made of a black alumite plate having a thickness of 1.0 mm. And a light shielding plate 33 made of a black alumite plate having a thickness of 0.3 mm, and only the outlet 33a of the ion flow is opened to the outside. The width of the open portion 33a is approximately 1 mm, and the creeping discharge along the dielectric 27 is inside the open portion with respect to the light shielding plate 33. There is no direct discharge light irradiation. This effect was obtained by charging the image carrier (for example, the photosensitive drum) 4 with the configuration shown in FIG. 4 as a charging device with or without the light shielding plate 33.
In the case where there was no 3, the charging potential did not reach 300 V, but in the case where the light shielding plate 33 was provided, a desired charging potential of 700 V or more could be obtained.

[Embodiment 11]
The configuration and operation of the invention according to the sixteenth embodiment and an embodiment will be described. In the present embodiment, as shown in FIG. 4, the ion generator 1 of "element 1" having a dielectric member having a large dielectric loss tangent is used.
The entire ion generator including the ion generator 3 of "element 2" having a dielectric member having a small dielectric loss tangent was used as a charging device. The configuration and operation of the “element 1” ion generator 1 made of a member having a large value of the dielectric loss tangent are as described in the above [Embodiment 1]. “Ion generator 2” ion generator 3 made of a member having a small dielectric loss tangent
Is similar to the configuration described in the example of [Embodiment 2] as shown in FIG. 5, and the second ion extraction electrode 34 shown in FIG. 5 has both surfaces of a stainless steel mesh coated with a photocatalyst. Things. The second ion extraction electrode 34 is a stainless mesh having a thickness of 0.3 mm, and the applied potential is positively high when viewed from the bias potential of the ion generators 1 and 3, and is substantially negative with respect to the ground, for example. It is kept at -0.55 kV. As a material for coating the electrode, for example, “T
iO MET "series materials were used. This is SUS
SUS powder is laminated on a mesh material, and anatase-type titanium dioxide (TiO ₂ ) is formed on the surface of the SUS powder. When ultraviolet light included in the discharge light hits the photocatalytic substance, ozone is decomposed into oxygen molecules due to strong oxidizing action.

The second ion extraction electrode 34 of the ion generator 3 functions to extract and drive out (repeller) negative ions, and at the same time, generate discharges such as ozone generated in the ion generator 1 and the ion generator 3. It has the effect of decomposing substances by activating the catalytic action. In order to confirm this effect, the result of evaluating the ozone concentration finally generated from the charging device having the configuration of FIG. The ozone concentration when using an electrode without a photocatalyst coating is 0.08 pp
In contrast, when the electrode coated with the photocatalyst was used, the ozone concentration was reduced to 0.03 ppm.

[Embodiment 12]
The configuration and operation of the invention according to the sixteenth embodiment and an embodiment will be described. The structure of the ion generator using the coaxial cylindrical discharge electrode shown in FIG. 1 or FIG. 2 that achieves both discharge when applying a high frequency voltage and heat retention of the member by using a dielectric member having a large dielectric loss tangent is shown in FIG. Embodiment 1] has the same configuration and operation as those described in (embodiments according to the first, fifteenth, and sixteenth inventions). In the embodiment of the present invention, as shown in FIG. 1, 25 coaxial cylindrical discharge electrodes are arranged at a length of 50 mm on one line. By arranging a plurality of fine discharge units having substantially the same discharge form in a line, it is examined whether or not the charging device can be actually formed into a shape in a case where a sheet width is required in a copying machine or the like. As a result, it was easy to arrange a large number of electrode units for the coaxial cylindrical discharge electrode. As an example, in order to configure a charging device having a length of 350 mm as the width of the charging device to correspond to the width of 296 mm of the A4 size paper, the coaxial cylindrical discharge electrode of FIG. 1 or FIG.
Five were arranged. When the drum current per unit length of the charging device was evaluated using the charging device provided with the ion extraction electrode on the left, a drum current of 1.78 μA was obtained per 10 mm of unit length of the charging device.

[Thirteenth Embodiment]
The configuration and operation of the invention according to the sixteenth embodiment and an embodiment will be described. In the present embodiment, as shown in FIG. 4, an ion generator 1 of "element 1" having a dielectric member having a large dielectric loss tangent
In a configuration in which the entire ion generator composed of the two elements of the "element 2" having a dielectric member having a small dielectric tangent is used as a charging device, "element 1" having a member having a large dielectric tangent is used. Is composed of a conductor electrode having a coaxial cylindrical shape and a dielectric member, or a conductor electrode having a parallel plate shape and a dielectric member, and has a member having a small dielectric loss tangent. The ion generator 3 of "2" is composed of a conductor electrode having a parallel plate shape and a dielectric member.

As the structure of the ion generator 1 of “element 1” having a dielectric member having a large dielectric loss tangent, the embodiment having the electrode unit of the coaxial cylindrical discharge electrode shown in FIG. 1 or FIG. Embodiment 12] is the same as the embodiment described in [Embodiment 12]. Using a parallel plate type discharge unit shown in FIG. 3 instead of the coaxial cylindrical discharge electrode, a charging device was formed to have a length of 350 mm, and the characteristics as an ion generator were examined. As a result, a discharge current of 880 μA was obtained. As a result, a drum current of 2.1 μA was obtained as a drum current per unit length of 10 mm of the charging device. Both the coaxial cylindrical discharge electrode and the parallel plate type discharge electrode can be easily formed as an element of a charging device of an arbitrary length, and use a dielectric member having a large value of a dielectric loss tangent.
Even when a high frequency band was applied, heat was generated due to an appropriate dielectric loss, so that it could be used as an element of the charging device without impairing the features of the present invention. On the other hand, the structure of the discharge electrode of the ion generator 3 using a dielectric member having a small value of the dielectric loss tangent is as shown in FIG. 5, but it is easy to make it into the width of the actual charging device. 350m as before
Those having a length of m were evaluated. In this case, a parallel plate type structure is most suitable because the advantage of the creeping discharge is positively used. Under the high-frequency power supply conditions described in detail above, a discharge current of 360 μA is obtained, and the structure is suitable for use as a charging device. A drum current per unit length of 10 mm of the charging device was 1.32 μA.

When the above two ion generators 1 and 3 are arranged and configured as shown in FIG. 4, the drum current per 10 mm length when the charging device is evaluated is 2.8 μA.
Met. The present inventors consider that the reason why the value of the drum current is not the sum of the drum currents of the individual ion generators may be the result of repeated neutralization and dissipation of the negative ions in the drift space. The unit length of the charging device is 10 units.
The amount of drum current of 2.8 μA per mm is 2 per minute.
The amount of ion current is too large to be used as a charging device such as a copying machine having a copying speed of five sheets.

[Embodiment 14]
The configuration and operation of the sixteenth invention will be described. An ion generator using a coaxial cylindrical discharge electrode structure as shown in FIG. 1 or FIG. 2 is described, for example, in [Embodiment 1] (Examples according to claims 1, 15, and 16). Similar to the configuration and operation described above, 25 units of coaxial cylindrical discharge electrodes may be arranged in a line to form a unit as an ion generator having a width of 50 mm, and a structure capable of connecting the common electrodes 9 and 10 may be made. Further, as another embodiment, as shown in FIG. 6, an ion generator composed of parallel plate type discharge electrodes having a fixed length is provided as a unit (parallel plate type discharge electrode unit) 3.
5, a plurality of the units 35 are connected in series or in parallel. Here, FIG. 6A shows an example in which parallel plate type discharge electrode units 35 having a length of 50 mm are connected in series, and FIG. 6B shows a case where the parallel plate type discharge electrode unit 35 is connected to fixed connection terminals 36. An example is shown in which the connection is made in parallel by using such a method. The fixed connection terminal 36 has a role of making the polarity and conditions applied to the individual electrodes common to all the units and a role of a holder, and is made of, for example, machinable ceramics having high insulation and good workability. In addition, by using both parallel connection and series connection, it is possible to cope with a case where a large charging width and high-speed processing are required. FIG. When a charging device was prototyped as the ion generator 1 of the “element 1” shown, a drum current of 6.8 μA was obtained per unit length of 10 mm of the charging device, and the dissipation of the ion current when charging the photosensitive drum was reduced. It has been found that it is possible to cope with the processing speed of a copying machine or the like, which is said to be a high-speed machine.

[Embodiment 15] Next, the structure and operation of the invention according to claim 17 and an embodiment thereof will be described. FIG.
FIG. 1 is a diagram showing an example of the configuration of an image forming apparatus. Reference numeral 41 denotes a photosensitive drum serving as an image carrier. Around the photosensitive drum 41, charging is performed to uniformly charge the surface of the photosensitive drum 41. A device 42, an optical writing device 43 for irradiating the charged photosensitive drum 41 with writing light (LB: laser beam) such as a laser beam to form an electrostatic image, and an electrostatic image on the photosensitive drum 41 with toner. A developing device 44 for developing and visualizing the image, a transfer device 47 for transferring the toner image on the photosensitive drum 41 to a transfer material S such as transfer paper, and a residual toner and paper dust on the photosensitive drum 41 after the transfer. A cleaning device 48 for removing, a charge removing device 49 for removing charge remaining on the photosensitive drum 41, and the like are provided. Further, in this image forming apparatus, a sheet feeding section 45 for feeding and transporting the transfer material S to a transfer section between the photosensitive drum 41 and the transfer device 47 and a registration roller 46, and the image is transferred to the transfer material S. A fixing device 50 for fixing the toner image is provided. In the present embodiment, in an image forming apparatus having a configuration as shown in FIG.
Charging device 4 for charging photoreceptor drum 41 to be charged
2, or as the transfer device 47 for transferring the visible image on the photosensitive drum 41 to the transfer material S or the charge removing device 49 for removing charge from the photosensitive drum 41 as described in the above [Embodiment 1] to
An ion generator (charging device) according to any one of [Embodiment 14] is mounted. Note that the configuration of the image forming apparatus is not limited to FIG. 10, and a multicolor image forming apparatus having an intermediate transfer body is also included in the present invention. The ion generator (charging device) of the present invention can be applied to an image forming apparatus provided with the image forming apparatus.

(Embodiment of the Seventeenth Invention) Next, a specific embodiment will be described. Embodiment 1 described above
An ion generator is manufactured with the configuration shown in 4, 5, and 12,
A prototype of a charging device having a width of 350 mm is manufactured as an actual image forming apparatus, for example, a copying machine manufactured by Ricoh: IMAGIO M
Mounted on F530. Here, Ricoh's copier: IM
Evaluation was made using the charging device of the present invention as a charging device for charging the photosensitive drum of AGIO MF530. The ozone concentration from the charging device main body was not more than 0.09 ppm, and the amount of ozone discharged outside the apparatus was not detected by the ozone concentration meter. In addition, the life of the photosensitive drum was able to maintain the initial physical properties even in a continuous charging / discharging running test corresponding to 200,000 sheets, and it was determined by analysis that no trouble occurred even in an operation corresponding to 350,000 sheets.

Next, an ion generator was manufactured with the configuration shown in Embodiments 2, 3, 6 to 11, and 13, and the ion generator was used as a charging device.
A prototype having a width of 50 mm was prototyped and mounted on an actual image forming apparatus, for example, a Ricoh copier: IMAGIO MF530. Here, a Ricoh copier: IMAGIO MF5
Evaluation was made using the charging device of the present invention as a charging device for charging 30 photosensitive drums. The ozone concentration from the charging device main body was 0.03 ppm or less, and the amount of ozone discharged to the outside of the device was not detected by the ozone concentration meter. In addition, the life of the photoconductor drum is continuously charged / equivalent to 280,000 sheets.
The initial properties were maintained in the static elimination running test, and it was determined by analysis that no problem would occur even when the operation was equivalent to 400,000 sheets. From the above results, it was concluded that all the effects of ozone and nitrogen oxides, which had a concern on the surface of the photoreceptor, could be removed.

[0070]

As described above, according to the first aspect of the present invention, a dielectric is disposed between conductor electrodes, and an electrode having a fine discharge space which is a substantially closed space sandwiched therebetween. An ion generator comprising a structure, applying an AC voltage between the conductor electrodes to generate charged particles by discharging,
The dielectric has a dielectric loss tangent of 3 among high-frequency dielectric properties.
It is characterized by having a value of 0 × 10 ⁻⁴ or more, forming a fine discharge space, and using a dielectric member having a large dielectric loss tangent value for the discharge electrode member, so that a high-frequency voltage in the kHz band can be obtained. Since the discharge space can be turned into a heat space field by discharging, it is possible to bring the discharge space to an optimum place for decomposing ozone. In addition, by accumulating a large number of fine discharge spaces as in the present invention, it becomes possible to easily cause charging of a member to be charged such as an image carrier. In addition, the decomposition of ozone is promoted by heating, but by using the present invention, ozone can be removed without providing a special heating device in the charging device, and 0.09 pp around the charging device.
m or less, and it is possible to substantially eliminate ozone discharge to the outside of the apparatus without providing a removing means such as an ozone removing filter.

According to a second aspect of the present invention, there is provided an electrode structure having a fine discharge space which forms a substantially closed space between the conductor electrodes by disposing a dielectric between the conductor electrodes. An ion generator that generates charged particles by discharging by applying an AC voltage to the element, the element comprising two elements, an element composed of a member having a large dielectric tangent and an element composed of a member having a small dielectric tangent. It has a fine discharge space and an element that secures a heat space suitable for ozone decomposition while generating enough ions for charging, and a thermal discharge material that has a fine discharge space and Because it has an element that generates ions to be used for charging while avoiding the effects, it is necessary to apply large electric energy to a single discharge space with a side of several millimeters to generate ions to be used for charging. Compared to a frequency 5 kHz, ion amount required for just charging applying a level of the AC voltage of the highest voltage (top value) 5 kV can be secured to. Also, 2
Since one ion generator is used, both functions of a means for removing a discharge product and a means for obtaining a large amount of ions can be used, so that high-speed charging can be realized. Further, in the discharge space, the input energy for discharge is less dissipated, the amount of ions required for charging can be secured at low voltage and low power consumption, and the generation of ozone and nitrogen oxides is small. Note that heat radiation from the heat space that promotes ozone decomposition does not directly affect a charged object such as an image carrier.

According to a third aspect of the present invention, there is provided an electrode structure having a fine discharge space which forms a substantially closed space between the conductor electrodes by disposing a dielectric between the conductor electrodes. An ion generator that generates charged particles by discharging by applying an AC voltage to the element, wherein the dielectric tangent of the dielectric is 30 × 10 ⁻⁴ or more.
Since it is characterized by being composed of two types of elements constituted by members of × 10 ^-4 or more, in addition to the same effect as in claim 2, a dielectric member having a dielectric loss tangent value of 30 × 10 ^-4 or more Has a function of maintaining a heat space suitable for ozone decomposition because of moderate heat generation in a frequency band of kHz, and decomposition of ozone becomes remarkable in a fine discharge space. Also, 10 × 1
Heat generation is small in a dielectric member having a dielectric loss tangent value of 0 ^-4 or less, and by arranging an element including the element on the side of a member to be charged such as an image carrier, the heat effect of a heat space suitable for ozone decomposition is reduced. It can be cut off and avoided.

In the prior art, a method is generally used in which large electric energy is applied to a single discharge space having a side of several millimeters to generate ions to be used for charging. On the other hand, the invention according to claim 4 is characterized in that, in the ion generator according to claim 1, the gap of the discharge space formed by the conductor electrode and the dielectric is 280 μm to 390 μm. In addition to the effect of 1 above, by arranging a large number of fine discharge spaces, ozone generated intensively in the ion generating portion is prevented, diffusion can be prevented, and decomposition can be performed in the heat space of the discharge field. Can be removed. When the gap in the discharge space is extremely small and does not reach 280 μm, the discharge starting voltage is lowered by Paschen's law, and discharge abnormalities such as short-circuiting are likely to occur.
If m is exceeded, the diffusion of discharge products is likely to occur, and the discharge starting voltage is too high, so that discharge is not generated at a low voltage and sparks frequently occur due to application of a high voltage. In this case, the reduction in efficiency, in which the amount of generated ions is small relative to the input energy, becomes remarkable.

In the invention according to claim 5, claim 1 is
In the ion generator described above, the frequency of the applied AC voltage is between 2.0 kHz and 5.0 kHz, and the leading value of the AC voltage is between 2.5 kV and 5.0 kV. Therefore, in addition to the effect of claim 1, by applying an AC voltage having a frequency of 5 kHz or less and a maximum voltage of 5 kV or less, low voltage, low power consumption,
Highly efficient ion generation is obtained. In the prior art, a high frequency (6 kHz or more) was often used to secure the amount of ions required for charging, but it was found that nitrogen oxides were likely to be generated. According to the present invention, it is possible to suppress nitrogen oxides that cause deterioration of a charged object such as an image carrier in association with moisture in the air and to efficiently generate ions that can reduce the capacity and shape of a discharge power supply. It is.

In the invention according to claim 6, claim 3
In the ion generator described above, the gap of the discharge space formed by the conductor electrode and the dielectric is 280 μm to 39
Since the thickness is 0 μm, in addition to the effect of claim 3, ozone intensively generated in the ion generating portion is prevented, diffusion is prevented, and decomposition is possible in the heat space of the discharge field. Can be removed. If the gap in the discharge space is extremely small and does not reach 280 μm, the discharge starting voltage is reduced by Paschen's law, and discharge abnormalities such as short circuits are likely to occur.
If m is exceeded, the diffusion of discharge products is likely to occur, and the discharge starting voltage is too high, so that discharge is not generated at a low voltage and sparks frequently occur due to application of a high voltage. In this case, the reduction in efficiency, in which the amount of generated ions is small relative to the input energy, becomes remarkable.

In the invention according to claim 7, claim 3
In the ion generator described above, the frequency of the applied AC voltage is between 2.0 kHz and 5.0 kHz, and the leading value of the AC voltage is between 2.5 kV and 5.0 kV. Therefore, in addition to the effect of claim 3, by applying an AC voltage having a frequency of 5 kHz or less and a maximum voltage of 5 kV or less, low voltage, low power consumption,
Highly efficient ion generation is obtained. Further, in the prior art, a high frequency (6 kHz) is used to secure an ion amount necessary for charging.
z or more) was applied in many cases, but it was found that nitrogen oxides were easily generated at such a high frequency. On the other hand, in the present invention, 5 kHz
Since an AC voltage having a frequency below 5 kV and a maximum voltage of 5 kV or less is applied, it is possible to suppress nitrogen oxides which may cause deterioration of a member to be charged such as an image carrier in association with moisture in the air, and to provide a discharge power source. Can be reduced in size and shape, and efficient ion generation can be achieved.

In the invention according to claim 8, claim 2
Or the ion generator according to item 3, characterized in that an element composed of a member having a large dielectric tangent generates ions by silent discharge, and an element composed of a member having a small dielectric tangent generates ions by creeping discharge. In addition to the effect of claim 2 or 3, in addition to applying an AC high frequency to a discharge electrode made of a member having a large value of dielectric loss tangent, a silent discharge is generated in the entire discharge space. Can be decomposed and removed. In this case, the action of heat is exerted on the entire discharge space to efficiently decompose ozone, and ions necessary for charging can be secured in the entire discharge space. On the other hand, the heat radiation from the heat space is
It is cut off by a discharge electrode made of a member having a small dielectric loss tangent and does not reach a member to be charged such as an image carrier. Further, in a discharge electrode having a small dielectric loss tangent, a creeping discharge is generated by the electrode structure and a discharge is generated along the electrode surface, so that the influence of heat and discharge light on a member to be charged such as an image carrier is avoided.

According to the second or third aspect of the present invention, an ion generator including an element using a dielectric member having a large dielectric loss tangent has a negative electric charge given a negative potential with respect to the ground. The discharged ions are released from the ion generator, but the ion alone does not act as a discharging force, and a small amount of current is obtained as a negative ion current with respect to the discharge current at the electrode outside the ion generator. Therefore, in the invention according to claim 9,
In addition to the configuration of the second or third aspect, by providing a first ion extraction electrode that gives a positively high potential to the ion generator, it is possible to obtain a negative ion current having a sufficient current amount for charging. it can. Similarly, for an ion generator composed of an element using a dielectric member having a small dielectric loss tangent, a second positive electrode having a higher positive potential and a higher positive potential than the first ion extraction electrode. By providing an ion extraction electrode, a large amount of negative ions can be drifted. Therefore, it is possible to efficiently extract an ion flow for charging from the two ion generators, and it is possible to simultaneously reduce power consumption and reduce discharge products.

In an electrophotographic image forming apparatus, a photoreceptor which generates light by sensing light is used as an image carrier. In such a case, the effects of light and heat degrade characteristics and life of the photoreceptor. Directly. Therefore, in a tenth aspect of the present invention, in addition to the configuration of the second or third aspect, a shielding plate for shielding discharge light is provided between an element made of a member having a small dielectric loss tangent and a member to be charged (photosensitive member or the like). Since unnecessary light is prevented from shining during charging of the photoreceptor or the like, the influence on the charging characteristics can be avoided. In addition, since surface discharge is particularly spread along the electrode surface, the discharge light is not concentrated at the center where the ions are emitted from the ion generator, and the light shielding plate is attached to the photosensitive member, etc. Unnecessary light irradiation can be completely prevented.

In the configuration of the second or third aspect, an ion generator composed of an element using a dielectric member having a large dielectric loss tangent has the effect of decomposing ozone in a heat space and removing most of it. The ozone and nitrogen oxides remaining without being removed together with the ions reach the ion generator, which is an element made of a dielectric member having a small dielectric loss tangent. Therefore, claim 1
In the invention according to the first aspect, in addition to the configuration of the second or third aspect, the second ion extraction electrode provided inside the element made of a member having a small dielectric loss tangent is maintained at a negative potential more than the surrounding discharge space. Since the surface of the ion extraction electrode contains a photocatalytic substance, the ions can be quickly drifted and the discharge products can be efficiently decomposed by the photocatalyst. That is, since the second ion extraction electrode is maintained at a positively higher potential than the first ion extraction electrode, the negative ions drift quickly and act to drive out the negative ions together with the extraction. Also,
Ozone and nitrogen oxides are easily decomposed by the photocatalyst. Since the discharge light contains many ultraviolet light components having a short wavelength and can easily activate the photocatalyst, the decomposition and removal of ozone and nitrogen oxides are efficiently performed.

According to a twelfth aspect of the present invention, in addition to the configuration of the first aspect, the electrode structure is composed of a conductor electrode having a coaxial cylindrical shape and a dielectric member. It is characterized in that the discharge space is individualized and miniaturized, so that the discharge energy loss in the discharge space is very small and uniformity can be ensured even for a large charging width. Also,
Since the discharge products can be prevented from being diffused and diffused and ions can be generated by applying a low-voltage, low-frequency alternating current, the amount of the discharge products themselves can be reduced. Further, according to the present invention, since it is possible to integrate a miniaturized discharge electrode, it is possible to form the charging device over an arbitrary charging width. It is. Further, even if a part of the charging device fails due to contamination or abnormal discharge, only the replacement of the failed unit is sufficient, so that there is a great merit in cost.

According to a thirteenth aspect of the present invention, in addition to the constitution of the second or third aspect, the element made of a member having a large dielectric loss tangent is constituted by a conductor electrode having a coaxial cylindrical shape and a dielectric member, or It is constituted by a conductor electrode having a parallel plate shape and a dielectric member, and the element made of a member having a small dielectric loss tangent is characterized by being constituted by a conductor electrode having a parallel plate shape and a dielectric member, Since an element using a dielectric member having a large tangent value (ion generator) and an element including a dielectric member having a small dielectric tangent value (ion generator) can be unitized, the same effect as that of the twelfth aspect is obtained. Can be In particular, an ion generator made of a dielectric member having a small dielectric loss tangent is easy to unitize a mechanism for avoiding the effects of heat and discharge light. It is possible to produce a charging device capable of realizing high performance (high-speed charging).

According to a fourteenth aspect of the present invention, in the ion generator according to the twelfth or thirteenth aspect, a unit in which a plurality of elements constituted by a conductor electrode having a coaxial cylindrical shape and a dielectric member are arranged is referred to as a unit. Or a unit composed of a pair of opposing parallel-plate-shaped conductor electrodes and a dielectric member, as a unit, having a structure that can be separated from and connected to each unit. It is characterized in that the charging width can be freely set, and when the charging device is configured with two types of elements (ion generators) as described in claim 2, discharge products such as ozone are extremely small. Thus, a charging device with low power consumption and high efficiency can be constructed. Further, if a basic unit of the ion generator having the function as in the present invention is designed and manufactured, a charging device having a long size and a large charging width can be easily configured by combining a plurality of these units. In addition, it is easy to design and manufacture according to the required charging speed, so that there is a great advantage in terms of manufacturing cost.
Further, even if a failure occurs in a part of the charging device for some reason, only the corresponding portion needs to be replaced, and the running cost and the component replacement cost during operation can be reduced.

According to a fifteenth aspect of the present invention, there is provided a charging method for charging a member to be charged.
The charged object generated by the ion generator is charged by using the ion generator according to any one of the items (4) to (5), so that the charged object is charged.
The same effect as any one of the above is obtained, a discharge method can be minimized in a non-contact state, and a charging method capable of high-speed charging can be realized. Also,
According to a sixteenth aspect of the present invention, there is provided a charging device for charging an object to be charged, comprising the ion generator according to any one of the first to fourteenth aspects, wherein a charge generated by the ion generator is provided. Since the object to be charged is characterized by being charged with particles, the same effect as any one of claims 1 to 14 can be obtained, and a discharge product can be minimized in a non-contact state, In addition, a charging device capable of high-speed charging can be realized.

According to the seventeenth aspect of the present invention, the image carrier as an object to be charged is charged, a latent image is formed on the image carrier, and the latent image is developed into a visible image. In an image forming apparatus for forming an image by transferring a visible image on an image carrier to a transfer material, a means for charging the image carrier as an object to be charged, or a visible image on the image carrier on a transfer material. The ion generator according to any one of claims 1 to 14, or the charging method according to claim 15, or the charging method according to claim 16, as a means for transferring or a means for removing charge from the image carrier. Since it is characterized by having a charging device, the same effect as any one of claims 1 to 16 can be obtained, and it can cope with high-speed charging required as an image forming apparatus.
Both high speed and reduction of ozone emission, which could not be solved by the prior art, can be solved at once. Therefore, to reduce the generation of discharge products such as ozone and NO _X, UL standards, T
An image forming apparatus that satisfies standards such as the UV standard and the BAM standard and enables high-speed recording can be realized. Further, in the invention according to the seventeenth aspect, since the discharge products are extremely small, the life of components around the charging device, for example, the photoreceptor is improved as compared with the prior art. Further, since the charging device can be easily made into a unit, costs related to manufacturing, running, and replacement of the charging device can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing an example of a charging device using an ion generator according to the present invention.

FIG. 2 is a cross-sectional view showing another configuration example of the coaxial cylindrical discharge electrode used in the ion generator according to the present invention.

FIGS. 3A and 3B are explanatory diagrams showing an example of a parallel plate type discharge electrode used in the ion generator according to the present invention, wherein FIG. FIG. 2 is a perspective view of a flat discharge electrode.

FIG. 4 is an explanatory diagram of a configuration and operation when the ion generator according to the present invention is used as a charging device.

FIGS. 5A and 5B are explanatory diagrams illustrating a configuration of another example of the ion generator according to the present invention, in which FIG. It is sectional drawing of the A 'line part.

FIG. 6 is an explanatory view showing the configuration of still another example of the ion generator according to the present invention, wherein FIG. 6 (a) shows the external appearance of an ion generator configured by connecting parallel plate type discharge electrode units in series and the connection part. FIG. 2B is a diagram showing the structure, and FIG. 2B is a diagram showing the external appearance of an ion generator configured by connecting parallel plate-shaped discharge electrode units in parallel and the structure of a connection portion.

FIG. 7 is an explanatory diagram of an ozone generation / decomposition rate and a decomposition reaction rate equation in a heat space.

FIG. 8 is an explanatory diagram of a gas flow in a model capillary.

FIG. 9 is an explanatory diagram of a concept of a charging method according to the present invention.

FIG. 10 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present invention.

[Explanation of symbols]

 1: Element 1 ion generator 2: First ion extraction electrode 3: Element 2 ion generator 4: Image carrier (photosensitive drum, etc.) 6: Central electrode 7: External induction electrode 8: Dielectric cylinder ( 9: Common electrode of center electrode 10: Common electrode of external induction electrode 11: AC power supply 12: Bias power supply 13: Bias power supply 14: Insulation support 15: First ion extraction electrode 16: Ion extraction power supply 17: Image Carrier (photosensitive drum etc.) 18: Drum current measuring device 19: Dielectric thin film 20: Metal cylinder 21: Slight gap 22: Insulator 23: Metal conductor electrode 24: Dielectric material having large dielectric loss tangent 25: Conductive electrode 26 : Discharge electrode 27: Dielectric material having small dielectric loss tangent 28: Embedded electrode 29: Linear electrode 30: AC high frequency power supply 31: Insulation support 32: Side wall 33: Light shielding plate 34 Second ion extraction electrode 35: parallel plate type discharge electrode unit 36: fixed connection terminal 41: image carrier (photosensitive drum) 42: charging device 43: optical writing device 44: developing device 45: paper feed unit 46: resist Roller 47: Transfer device 48: Cleaning device 49: Static elimination device 50: Fixing device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Tatsuya Sato, Inventor 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Hiroshi Kondo 1-3-6, Nakamagome, Ota-ku, Tokyo・ F-term in Ricoh Co., Ltd. (reference) 2H003 AA18 BB11 BB14 BB16 CC01 EE08 EE12 2H032 AA02 BA23 2H035 AA02 AA03 AA04 AA05 AB03 CA07 CB01 5G067 AA65 DA19

Claims (17)

[Claims] An electrode structure having a fine discharge space defining a substantially closed space interposed between the conductor electrodes, and applying an AC voltage between the conductor electrodes. An ion generator for generating charged particles by discharge, wherein the dielectric has a dielectric loss tangent of 3 among high-frequency dielectric characteristics.
An ion generator having a value of 0 × 10 ⁻⁴ or more. 2. An electrode structure comprising a dielectric material disposed between conductor electrodes and having a fine discharge space defining a substantially closed space interposed therebetween, and applying an AC voltage between the conductor electrodes. An ion generator for generating charged particles by discharging, comprising: an element composed of a member having a large dielectric tangent and an element composed of a member having a small dielectric tangent. 3. An electrode structure having a fine discharge space defining a substantially closed space sandwiched between the conductor electrodes by providing a dielectric between the conductor electrodes, and applying an AC voltage between the conductor electrodes. An ion generator for generating charged particles by discharge, wherein a value of a dielectric loss tangent of the dielectric is 30 × 10 ⁻⁴ or more and 10 × 10 ⁻⁴ or more. An ion generator comprising two types of elements. 4. The ion generator according to claim 1, wherein the gap of the discharge space defined by the conductor electrode and the dielectric is 280 μm to 390 μm. 5. The ion generator according to claim 1, wherein the frequency of the applied AC voltage is from 2.0 kHz to 5.0 kHz.
Hz, and the leading value of the AC voltage is 2.5 k
An ion generator characterized by being between V and 5.0 kV. 6. The ion generator according to claim 3, wherein the gap of the discharge space defined by the conductor electrode and the dielectric is 280 μm to 390 μm. 7. The ion generator according to claim 3, wherein the frequency of the applied AC voltage is 2.0 kHz to 5.0 kHz.
Hz, and the leading value of the AC voltage is 2.5 k
An ion generator characterized by being between V and 5.0 kV. 8. The ion generator according to claim 2 or 3, wherein an element composed of a member having a large dielectric tangent generates ions by silent discharge, and an element composed of a member having a small dielectric tangent generates ions by creeping discharge. An ion generator characterized by being generated. 9. The ion generator according to claim 2, wherein a first ion extraction electrode is provided between an element made of a member having a large dielectric tangent and an element made of a member having a small dielectric tangent. An ion generator, wherein a second ion extraction electrode is provided inside an element made of a member having a small dielectric loss tangent. 10. The ion generator according to claim 2, wherein a shield plate for shielding discharge light is provided between an element made of a member having a small dielectric loss tangent and the member to be charged. Ion generator. 11. The ion generator according to claim 2, wherein the second ion extraction electrode disposed inside the element made of a member having a small dielectric loss tangent is kept at a negative potential more than the surrounding discharge space. An ion generator, wherein the surface of the ion extraction electrode contains a photocatalytic substance. 12. The ion generator according to claim 1, wherein the electrode structure is composed of a conductor electrode having a coaxial cylindrical shape and a dielectric member, and a large number of said electrode structures are linearly arranged. And an ion generator. 13. The ion generator according to claim 2, wherein the element made of a member having a large dielectric loss tangent is made up of a conductor electrode having a coaxial cylindrical shape and a dielectric member, or a conductor having a parallel plate shape. An ion generator comprising an electrode and a dielectric member, wherein the element made of a member having a small dielectric loss tangent is composed of a conductor electrode and a dielectric member having a parallel plate shape. 14. An ion generator according to claim 12, wherein a plurality of elements each comprising a conductor electrode having a coaxial cylindrical shape and a dielectric member are disposed as a unit, or a pair of opposing elements is provided. As a unit composed of a parallel plate-shaped conductor electrode and a dielectric member, each unit has a structure that can be separated and brought into contact with each other, and it is possible to freely set an arbitrary charging width by combining an arbitrary number of units. Characterized ion generator. 15. A charging method for charging an object to be charged, wherein the ion generator according to any one of claims 1 to 14 is used, and is charged by charged particles generated by the ion generator. A charging method characterized by charging a body. 16. A charging device for charging an object to be charged, comprising: the ion generator according to claim 1; A charging device for charging a body. 17. An image bearing member to be charged is charged, a latent image is formed on the image bearing member, and the latent image is developed into a visible image. In an image forming apparatus for transferring an image to a transfer material to form an image, a means for charging an image carrier as an object to be charged, or a means for transferring a visible image on the image carrier to a transfer material, or an image carrier As means for neutralizing a body, the ion generator according to any one of claims 1 to 14, the charging method according to claim 15, or the charging device according to claim 16 is mounted. Characteristic image forming apparatus.