Discharge device, surface modification device, and plant growth device

Abstract

To generate a high concentration radical.SOLUTION: A discharge tube includes: a dielectric with a hollow cylindrical shape and uniform thickness, to pass a modification object material to be ionized; one or more conductive rods installed inside the dielectric parallel to the dielectric so that the distance from the dielectric is kept uniform; and a conductor covering a surface of the dielectric. A voltage is applied between the conductive rod with electrical insulation structure and the conductor, and the modification object material is modified by inputting and outputting the modification object material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention , release The present invention relates to an electrical device, a surface modification device, and a plant cultivation device. [Background technology]

[0002] Ozone, which tends to remain as radicals, has been attracting attention as a highly safe disinfectant due to its potent bactericidal activity against microorganisms, conidia, and fungal cells, and its easy decomposition into oxygen. Radicals are poorly soluble in water. For example, ozone is difficult to dissolve in water, so if it can be dissolved and concentrated as ozone water, it can be used as a powerful disinfectant. Furthermore, once dissolved, ozone returns to its original state within a few minutes at most, making it a harmless, non-pesticide. This effect occurs when high voltage is applied to a dielectric zone (such as water, aqueous solutions, or media containing water vapor as the main components of the material to be modified), and it is known that a wide variety of radicals other than ozone are generated. This radical is classified as plasma, which is generated when high voltage is applied to air, etc., to separate molecules and ions, and is generated in the final stage of radical generation.

[0003] The oxidizing power of ozone water has been put to practical use in many fields for sterilization and deodorization, and the mechanisms of its use in activating cells, such as cleansing and revitalizing the skin, have been elucidated, and research into its usefulness for the human body, from burn treatment to cosmetic purposes, is being published year after year. These effects are most pronounced when the ozone water concentration is in the 1-5 ppm range.

[0004] Currently, there are three widely disclosed methods for producing ozone water for medical and industrial use: the gas dissolution method, in which ozone is dissolved in ozone gas generated by electrical discharge; the electrolytic gas dissolution method, in which ozone gas generated by electrolysis is dissolved in water; and the direct electrolysis method, in which raw water is brought into direct contact with an electrolytic surface to produce ozone water.

[0005] For example, Patent Document 1 discloses a technique that utilizes direct electrolysis, in which raw water is brought into direct contact with an electrolysis surface to generate ozone water. Summary of the Invention [Problem to be solved by the invention]

[0006] Currently, types of discharge are roughly classified according to the behavior of the accompanying current. The region where the voltage increases as the current increases, showing a positive correlation with the discharge current, is called a "corona discharge." The region where there is almost no voltage fluctuation even when the current increases is called a "glow discharge." Finally, the region where the voltage drops dramatically despite the large current flow is called an "arc discharge." Arc discharge, in particular, generates a very large amount of heat due to the extremely large current that flows.

[0007] Corona discharges and barrier discharges under atmospheric pressure generate filament-like discharges. These are called streamer discharges. Streamer discharges are used in many fields, including environmental improvement technology, ozone generation, biology, medicine, surface treatment, and combustion support, and the active species (radicals, ions, excited species, etc., such as O, N, OH, and O3) generated by the discharge play an important role. For example, in environmental improvement technology, the active species generated by the discharge, such as O, N, OH, and O3, decompose and remove environmental pollutant gases (NOx, SOx, volatile organic compounds, etc.) and environmental pollutants in water (chemicals, bacteria, etc.).

[0008] In biotechnology (sterilization), the bactericidal reactions of active species and the electrostatic breakdown of cell membranes by ions are thought to be effective. In medical technology (hemostasis, wound treatment, cancer treatment, dental treatment), the reactions of active species generated by discharge are also thought to be effective in treatment. In combustion support technology, fuel is converted into radicals by discharge and then burned, increasing the efficiency of the combustion reaction, which is a chain reaction of radicals. In this way, active species are important in applied technologies of streamer discharge, and measurement of active species is essential for technological development. As active species generally have a short lifetime (<1 ms), "in situ" measurement using laser spectroscopy is used for measurement.

[0009] However, laser measurement requires large-scale equipment and is not easy to perform, and few examples of streamer discharge measurements have been reported. Streamer discharges use various voltages, including DC, AC, and pulsed currents, but all discharges are pulsed discharges lasting from 10 to several hundred nanoseconds. Electrons of approximately 1 to 10 eV are generated during the discharge and collide with neutral particles in the background gas. The background gas is often air, and collision reactions occur with N2, O2, and H2O in the air. As a result, radicals such as N, O, OH, and H are generated through collision dissociation reactions (e.g., e + O2 → e + O + O) and attachment dissociation reactions (e.g., e + O2 → O- + O). Furthermore, ions such as N2+, N4+, N+, O2+, O4+, O+, O2-, O-, H2O+, and H-, as well as excited species such as N, N(2D), and O(1D), are also generated. In addition to electron collision reactions, reactive species are also generated through chemical reactions of reactive species.

[0010] In the NOx removal process, the activated species thus generated react and remove NOx within a time period of 1 μs to 1 ms after discharge. NOx is removed primarily through a reduction reaction with N radicals. Alternatively, NOx can be removed through an oxidation reaction with O, O3, and OH radicals.

[0011] The products of the oxidation reaction, NO2 and HNO3, can be reduced in solution and recovered. Whether the oxidation or reduction reaction is the main reaction path depends on the discharge conditions. Actual reactions are far more complex than this, and the simulation takes into account tens to hundreds, and in some cases nearly 1,000, reaction equations. The "primary radicals" of radical and NOx concentrations are radicals such as O, N, and OH that are generated by electron collisions. Primary radicals are generated by the discharge pulse and then decrease due to various reactions with a time constant of 1 μs to 1 ms.

[0012] "Secondary radicals" refer to O3, HO2, etc., which are produced by reactions with primary radicals. Secondary radicals are produced 1 to 100 μs after discharge and then decrease with a time constant of 100 μs to 10 ms (in some cases, 1 s or more). NOx decreases by reacting with the primary and secondary radicals.

[0013] This reaction flow is the same in biotechnology, medicine, surface treatment, and combustion support. In all cases, the key is the reaction of activated species generated by discharge.

[0014] The present invention has been made in view of the above, and has an object to generate radicals at a high concentration. [Means for solving the problem]

[0015] In order to solve the above-mentioned problems and achieve the object, the present invention provides a hollow cylindrical dielectric body having a uniform thickness, through which a material to be modified, which is to be ionized, passes; one or more conductive rods installed inside the dielectric body in parallel to the dielectric body so as to maintain a uniform distance from the dielectric body; and a conductor covering the surface of the dielectric body, wherein a voltage is applied between the conductive rods and the conductor, which are electrically insulated, to input and output the material to be modified. a discharge device including a plurality of discharge tubes, which circulates the material to be modified in multiple stages in sequence within the dielectric of the plurality of discharge tubes, and which includes three or more discharge tubes each having a different number of conductive rods, thereby forming three or more electrodes electrically connected in parallel or series; and among the three or more electrodes each having a different number of conductive rods, the air gap length between the dielectric and the conductive rods is kept the same, while the number of the conductive rods is increased in sequence and the cross-sectional area of ​​the conductive rods is reduced, thereby adjusting the distributed capacitance between the conductive rods and the conductor to be the same. It is characterized by: [Effects of the Invention]

[0016] The present invention has the effect of enabling the generation of radicals at a high concentration. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view showing the configuration of a discharge tube according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of the discharge tube. [Figure 3] FIG. 3 is a diagram showing a state in which fins are provided on the surface of a dielectric. [Figure 4] FIG. 4 is a diagram showing a general example of calculation of capacitance. [Figure 5] FIG. 5 is an enlarged view of a part of the discharge tube. [Figure 6] FIG. 6 is a block diagram showing an example of a control configuration for a discharge tube. [Figure 7]FIG. 7 is a diagram showing an equivalent circuit when the diameter of the dielectric material and the number of conductive rods of a plurality of discharge tubes according to the second embodiment are changed. [Figure 8] FIG. 8 is a diagram showing an example of the measurement results of ion chromatography. [Figure 9] FIG. 9 is a diagram showing the configuration of a device including a discharge tube according to the third embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing the configuration of a discharge tube. [Figure 11] FIG. 11 is a perspective view showing the configuration of the cylinder. [Figure 12] FIG. 12 is a configuration diagram showing only the essential parts of a discharge device according to the fourth embodiment and an image forming apparatus including the discharge device. [Figure 13] FIG. 13 is a schematic diagram showing an example of a plant growing device used in the plant growing method according to the fifth embodiment. [Figure 14] FIG. 14 is a diagram showing an example of a plant growing device used in the plant growing method according to the sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the discharge tube, the discharge device, the surface modification device, and the plant growing device will be described in detail with reference to the accompanying drawings.

[0019] (First embodiment) Here, Figure 1 is a perspective view showing the configuration of a discharge tube 1 in the first embodiment, Figure 2 is a cross-sectional view showing the configuration of the discharge tube 1, and Figure 3 is a diagram showing the state in which fins 6 are provided on the surface of a dielectric 2.

[0020] As shown in FIGS. 1 and 2, the discharge tube 1 includes a hollow, cylindrical dielectric 2 of uniform thickness. The dielectric 2 is, for example, quartz glass made of silica (SiO2). The quartz glass has a thickness of, for example, 2 mm. Inside the dielectric 2, the discharge tube 1 includes conductive rods 3, which are conductors arranged parallel to the dielectric 2 so that a uniform distance is maintained between the dielectric 2 and the conductive rods 3. The number of conductive rods 3 can be selected to be one or more. As shown in FIG. 2, in the discharge tube 1 of this embodiment, the number of conductive rods 3 provided inside the dielectric 2 is, for example, five. The five conductive rods 3 are arranged in a circle in the hollow portion of the dielectric 2.

[0021] In addition, the surface of the discharge tube 1 is covered with a conductor 4. An electrode 5 is provided on each end of the discharge tube 1. In the discharge tube 1, a voltage is applied between the electrically insulating conductive rod 3 and the conductor 4 via the electrode 5.

[0022] The discharge tube 1 passes the material to be ionized through the hollow portion inside the dielectric 2. The material to be modified can be, for example, a liquid (water, ammonia, organic matter, etc.), a gas (air, gas, etc.), an ion, or a radical. The discharge tube 1 can be used to modify or increase the radical or ion concentration of a liquid (water, ammonia, organic matter, etc.), a gas (air, gas, etc.), an ion, or a radical.

[0023] The electrodes 5 at both ends of the discharge tube 1 are selected from materials with good heat dissipation properties, such as Al or Cu, because radicals are hardly generated on the outer periphery of the discharge tube 1.

[0024] The ideal conductive rod 3 is one with a small skin depth, rather than one with a large skin depth, such as Cu or Al, where the current is 1 / e (≒ 1 / 2.718 ≒ -8.7 dB) of the surface current. For example, the skin depth of the skin current of magnetic metals is significantly shallower than that of diamagnetic metals. Therefore, to achieve creeping discharge characteristics, a shallow skin current depth is preferable, and magnetic metals are superior to Cu or Al. Furthermore, a conductive rod 3 with corrosion resistance and hardness is suitable. In other words, a conductive rod 3 with a large skin current is preferable. Materials for the conductive rod 3, such as elemental metals from Groups 4 to 6, such as titanium (Ti), vanadium (V), Ta, or Nb, or alloys primarily composed of the precious metals Pt or Au, are oxidation-resistant and corrosion-resistant.

[0025] 3, the discharge tube 1 is provided with fins (heat sinks) 6 on the surface of the dielectric 2. The discharge tube 1 dissipates heat on the surface of the cylindrical dielectric 2.

[0026] Here, Fig. 4 is a diagram showing a general calculation example of capacitance. In the example shown in Fig. 4, the area S [m 2 ], distance d [m]. The dielectric constant of the vacuum between the two parallel conductors is assumed to be ε0. When a charge of +Q [C] is applied to one conductor and a charge of -Q [C] is applied to the other conductor, a uniform electric field is created between the plates, and if this is expressed as E [V / m], then the following relationship holds according to Gauss's law: E=Q / εs·ε0·S Also, if the voltage between the flat conductors is V [V], the following equation is obtained, and the capacitance C [f] of this object can be calculated. C=Q / V=Q / Ed=εs·ε0·S / d

[0027] In the discharge tube 1 of this embodiment, the distance applied between the electrode + and electrode - is 4 mm at most, as will be described in detail later. In the discharge tube 1 of this embodiment, the dielectric 2 of a uniform thickness and the modification target material of a uniform thickness are arranged in a circular shape at a uniform distance between the electrode + and electrode -. As a result, the voltage applied to the dielectric 2 becomes a uniform streamer discharge (a type of corona discharge) and does not become an arc discharge.

[0028] Here, Figure 5 is an enlarged view of a portion of the discharge tube 1. As shown in Figure 5, the voltages applied to each are connected in series due to the relative permittivity of the air gap length d1 between the dielectric 2 and the conductive rod 3 and the thickness length d2 of the dielectric 2, which is quartz glass, and therefore the reciprocal ratio is applied. That is, assuming d1:εs=1, d2=4, and d1=d2, and the amount of charge Q inside the discharge tube 1 is the same, a voltage of 4 / 5 is applied to the air gap length d1 between the dielectric 2 and the conductive rod 3, and a voltage of 1 / 5 is applied to the thickness length d2 of the dielectric 2.

[0029] The material to be modified is modified as it passes through the air gap length d1 between the dielectric 2 and the conductive rod 3, but it acts on the creeping discharge part that spreads like a skirt beyond the dashed line area shown in Figure 5. Note that the part with a short distance only results in a loss of light and heat. Paschen's law states that the applied voltage is 3 kV / mm at atmospheric pressure (1 atmosphere), so if d1 + d2 = 4 mm, it becomes 12 kV.

[0030] Therefore, in order to increase the area of ​​the creeping discharge portion that spreads like a skirt, it is better to provide multiple (for example, two) conductive rods 3 spaced apart rather than one conductive rod 3 as shown in Fig. 5. Therefore, in this embodiment, multiple conductive rods 3 are arranged in a circle in the hollow portion inside the dielectric 2.

[0031] In this case, for manufacturing reasons, the distance between the conductive rods 3 should be at least 1 mm (preferably the diameter of the conductive rods 3), which has the effect of suppressing the attractive force of currents flowing in the same direction (the force of attraction between the conductive rods 3). On the other hand, the conductive rods 3 exhibit a skin effect. The skin effect is a phenomenon in which, when an alternating current flows through a conductor, the current density is high on the surface of the conductor and decreases as the distance from the surface increases. Therefore, the higher the applied frequency of the conductive rods 3, the more likely it is that current will only flow through the skin. For this reason, it can be seen that providing multiple conductive rods 3 is more effective than making the conductive rods 3 thicker.

[0032] Here, Fig. 6 is a block diagram showing an example of the control configuration of the discharge tube 1. Since the insulation resistance differs depending on the material to be modified, the current flowing due to the dielectric barrier discharge that generates radicals also differs. Therefore, as shown in Fig. 6, in this embodiment, the value of the current flowing due to the dielectric barrier discharge that generates radicals is detected by a CT (current transformer) 30 or the like provided on the wiring that supplies power from the inverter 20 to the discharge tube 1. The CT (current transformer) 30 feeds back the detected amount to the inverter 20, automatically controlling the amount supplied from the inverter 20 and controlling the amount supplied by the inverter 20.

[0033] That is, in this embodiment, the applied voltage is an alternating voltage, and the applied voltage range is automatically adjusted depending on the value of the current that flows when the voltage is applied.

[0034] In this way, by making the air gap length d1 between the dielectric 2 and the conductive rod 3 the same distance as the thickness d2 of the dielectric 2, and applying an alternating voltage between the conductive rods 3, weak, uniform electric lines of force are generated, resulting in a discharge (streamer). Furthermore, if there is a part with low impedance or poor insulation somewhere, a large current will flow there, causing an arc discharge and creating a hole in the dielectric 2, not only causing insulation breakdown but also overloading the inverter that applies the voltage, which may lead to failure in the worst case scenario.

[0035] The length of the conductive rods 3 depends on the conductivity of the metal material, but shorter is better. In this embodiment, the conductive rods 3 are 200 mm / 10 W, φ0.3 to φ12, and there are 2 to 50 of them. In this case, the capacitance is 10 to 500 pF.

[0036] As described above, according to this embodiment, a plurality of conductive rods 3 are arranged in a circle inside the hollow cylindrical dielectric 2 of uniform thickness, and the discharge tube 1 dissipates heat on the surface of the cylindrical dielectric 2. This allows for a structure in which the material to be modified is introduced into the hollow part inside the dielectric 2 through the tube, and is generated and output by the discharge tube 1, thereby enabling the generation of high-concentration radicals.

[0037] Although the present embodiment uses a single discharge tube 1, this is not limiting. For example, multiple discharge tubes 1 may be provided, and the material to be ionized may be circulated sequentially within the hollow portion of the dielectric 2. More specifically, multiple discharge tubes 1 may be connected by a silicone tube or the like to serially modify the material to be modified. This configuration allows radicals to be generated and their concentration to increase in the next discharge tube 1, naturally improving the effect. However, because the discharge tube 1 is capacitive, if the voltage waveform of the inverter 20 applied is resonant with the load, the voltage waveform becomes dull and does not change sharply. However, otherwise, the power that can be applied to the load is simply proportional to the capacitance C of the object. Therefore, using the same discharge tube 1 alone can achieve twice the effect.

[0038] (Second embodiment) Next, a second embodiment will be described.

[0039] The second embodiment differs from the first embodiment in that the diameter and number of conductive rods 3 in the hollow portion of the dielectric 2 are changed, and the respective distributed capacitances are adjusted by the number of conductive rods 3. In the following explanation of the second embodiment, explanation of the same parts as in the first embodiment will be omitted, and only the parts that differ from the first embodiment will be explained.

[0040] Fig. 7 is a diagram showing an equivalent circuit when the diameter of the dielectric 2 and the number of conductive rods 3 of a plurality of discharge tubes 1 according to the second embodiment are changed. The example shown in Fig. 7 shows that the diameter of the dielectric 2 and the number of conductive rods 3 are changed, and the respective distributed capacitances are adjusted by the number of conductive rods 3, and a configuration of three discharge tubes 1 is shown with first electrode C1 to third electrode C3. The following shows the verification results when the inner diameter φ21 and outer diameter φ25 of the dielectric 2 of the discharge tube 1 are shown. First electrode (C1): 7, 40 pF (10 kHz), φ3 (large electric field lines / electrode) Second electrode (C2): 15 pieces, 41 pF (10 kHz), φ1 (in the electric field line / piece) Third electrode (C3): 29 pieces, 43 pF (10 kHz), φ0.3 (small electric field lines / piece)

[0041] In the example shown in Figure 7, the first electrode (C1), which is the discharge tube 1, first takes advantage of the small number of lines to produce strong electric field lines (discharge lines) per line. Next, when the electric field lines enter the second electrode (C2), the greater number of electric field lines per line produces a weaker discharge than at the first electrode (C1). Next, when the electric field lines enter the third electrode (C3), the greater number of electric field lines per line produces an even weaker discharge. This allows the concentration of radicals to gradually increase by first ionizing those with a high energy binding force with strong electric field lines.

[0042] In terms of power, a configuration with three discharge tubes 1 applies three times the power. Also, radicals require 1 to 10 eV (when reforming air), and since they usually disappear within 1 msec, it is desirable to set the application cycle to 1 / msec, or 10 kHz or higher. Because this structure prevents radicals from disappearing quickly, circulating them multiple times or more will generate radicals with a higher density (concentration).

[0043] In this embodiment, the second electrode is configured with three or more electrodes (discharge tubes 1). The second electrode has an area less than one times the area S of the conductive rods 3, which are the conductors of the first electrode, and the distributed capacitance between the conductive rods 3 and the conductor 4 is adjusted by the number of conductive rods 3. The second electrode, whose distributed capacitance between the conductive rods 3 and the conductor 4 is adjusted, has the same air gap length (d1) as the first electrode, but the area of ​​the conductive rods 3 is reduced so that the distributed capacitance is approximately the same as that of the first electrode, and the number of conductive rods 3 is increased accordingly, so that the capacitance range is within ±30%.

[0044] Air, an example of a material to be reformed, is in a molecular state, but from the beginning, weak electric field lines like those of the third electrode (C3) cannot sufficiently reform the material due to its large potential energy. Acceleration is required to gradually change it into kinetic energy. The role of acceleration is to maintain the same capacity (to make the applied power the same) and to expand the amount of creeping discharge (skirt area).

[0045] As a result of the experiment, when the conductive rod 3 was made of Cu, which is easy to see the changes in properties, and 8 kV, 22 kHz, and 15 W were applied, after 4 hours, rust was generated at the third electrode due to the oxidation reaction of OH radicals, and rust was generated at the second electrode due to the oxidation reaction of O radicals and OH radicals. Also, rust oxidation reaction of O radicals was observed at the first electrode. In this way, it is thought that the first thing generated is the decomposition of O2, followed by the decomposition of molecules bonded to OH. By using this configuration, it is possible to extract only the radicals generated near each electrode.

[0046] The ion chromatography measurement results one day after dissolving the reformed air in pure water (purchased product) showed the following results. Figure 8 shows an example of the ion chromatography measurement results. Figure 8(a) shows the measurement results of chromatography using an ECD detector, and Figure 8(b) shows the measurement results of chromatography using a UV detector. In Figure 8(a), the parts marked "No" indicate that an unknown peak has appeared. No. 1 in Figure 8 shows the state of the pure water, and No. 2 shows the state of the ion chromatography measurement one day later. However, while it is known that nitric acid, sulfuric acid, chlorine, etc. remain in ionic form, it has not been possible to determine whether radicals remain.

[0047] (Third embodiment) Next, a third embodiment will be described.

[0048] The third embodiment differs from the first embodiment in that a cylinder is provided parallel to the conductive rod to make the distribution of radicals inside the electrode uniform. In the following explanation of the third embodiment, the explanation of the same parts as in the first embodiment will be omitted, and only the parts that differ from the first embodiment will be explained.

[0049] Fig. 9 is a diagram showing an apparatus configuration including a discharge tube 1 according to a third embodiment. The apparatus configuration shown in Fig. 9 includes three discharge tubes 1 and 11 indicated by first electrode C1 to third electrode C3. The apparatus configuration shown in Fig. 9 is configured so that the material to be modified to be ionized is supplied sequentially to the first electrode C1 to third electrode C3 and then returned to the initial supply location.

[0050] 10 is a cross-sectional view showing the configuration of a discharge tube 11. As shown in FIG. 10, in the discharge tube 11 that serves as the second or third electrode, the number of conductive rods 3 provided inside the dielectric 2 is, for example, four. In addition, in the discharge tube 11 that serves as the second or third electrode, a cylinder 12 is provided parallel to the conductor (conductive rod 3) inside the second electrode to make the distribution of radicals inside the electrode uniform. The four conductive rods 3 and cylinder 12 are provided in a circular arrangement in the hollow part of the dielectric 2.

[0051] Here, Fig. 11 is a perspective view showing the configuration of cylinder 12. As shown in Fig. 11, cylinder 12 is hollow inside and is made of resin or an oxidation-resistant material (such as woven fibers of a metal material such as titanium). Cylinder 12 has a large number of holes 12a on its surface. This configuration allows for uniform distribution of radicals inside the electrode.

[0052] That is, the second and third electrodes other than the first electrode are equipped with a cylinder 12 to uniformly distribute radicals inside the electrodes, and the material to be reformed is circulated from the cylinder 12 into the inside of the discharge tube. This results in the generation of radicals with a higher density. The material to be reformed that enters in this way is reformed down to radicals, and is not limited to gas or liquid. The uniform distances d1 and d2 in Figure 5 prevent the discharge from becoming an arc, but rather a uniform streamer discharge.

[0053] In this way, by providing the second electrode and the third electrode with the cylinder 12 for making the distribution of radicals inside the electrodes uniform, the radical concentration inside the electrodes can be made uniform.

[0054] When electrodes are provided after the third electrode, the electrodes provided after the third electrode have the same configuration as the second and third electrodes, and the number of electrodes is not limited.

[0055] (Fourth embodiment) Next, a fourth embodiment will be described.

[0056] The fourth embodiment differs from the first embodiment in that the discharge device of the first to third embodiments is applied to a sheet surface modification device. In the following description of the fourth embodiment, the description of the same parts as the first to third embodiments will be omitted, and only the parts that differ from the first to third embodiments will be described.

[0057] [Embodiments of Discharge Device and Image Forming Apparatus] Next, an embodiment of a discharge device according to the present invention and an image forming apparatus including the discharge device will be described with reference to Fig. 12. Fig. 12 is a configuration diagram showing only the essential parts of an embodiment of a discharge device and an image forming apparatus including the same according to a fourth embodiment.

[0058] The discharge device 50 comprises a high-voltage inverter device 51, a roller-shaped discharge electrode 52, a counter electrode 53, and a sleeve-shaped dielectric 54 integrally provided on the outer periphery of the counter electrode 53. The discharge electrode 52 comprises a rod-shaped metal body 52a made of a highly conductive metal such as copper or aluminum, and an insulator (dielectric) 52b covering the outer periphery thereof.

[0059] The discharge electrode 52 and the counter electrode 53 face each other with a dielectric 54 interposed therebetween, and are rotatably supported above and below the sheet material conveying path, respectively.

[0060] The high-voltage inverter device 51 is the inverter 20 according to the present invention described above, and has an output terminal 2a connected to a metal body 52a of a discharge electrode 52 and an output terminal 2b connected to earth. Meanwhile, a counter electrode 53 is also connected to earth.

[0061] Therefore, a pulsating high voltage of several tens of kilovolts output from the high-voltage inverter device 51 is applied in the atmosphere between the metal body 52a of the discharge electrode 52 and the counter electrode 53. This generates an atmospheric pressure plasma discharge from the discharge electrode 52 toward the counter electrode 53, and plasma is formed along the surface of the dielectric 54. This discharge is also called a creeping discharge, a silent discharge, or a dielectric barrier discharge.

[0062] A pair of conveying rollers 71 is provided so that the sheet material S can be conveyed between the discharge electrode 52 and the dielectric 54 of this discharge device 50, and guide plates 72 and 73 are provided on both sides of the dielectric 54 and the counter electrode 53 to form a conveying path.

[0063] The sheet material S may be plain paper or coated paper used for copying or printing, resin film including overhead projector sheets, thick paper such as cards and postcards, or envelopes, and its surface is modified by contacting it with plasma through the gap between the discharge electrode 52 and the dielectric 54 of the discharge device 50. The modification process is a process that makes the water-repellent surface of the sheet material hydrophilic (increases wettability).

[0064] At this time, the counter electrode 53, which is an integral part of the discharge electrode 52 and the dielectric 54, rotates along with the movement of the sheet material S, so that plasma is generated uniformly and the entire surface of the sheet material S is modified uniformly.

[0065] Thus, in this embodiment, the discharge device 50 serves as a sheet material modifying device, and an image forming section 60 that forms an image on the sheet material is provided downstream in the sheet material conveying direction, thereby forming an image forming apparatus.

[0066] The image forming section 60 is provided with a head unit 61 having line-type inkjet heads 61y, 61m, 61c, and 61k of four colors: yellow (Y), magenta (M), cyan (C), and black (K).

[0067] Therefore, this image forming section 60 is an inkjet type image forming section, and further, is an image forming section that uses a full-color line-type inkjet head.

[0068] In FIG. 12, members for preventing the ink from drying in each inkjet head are not shown.

[0069] Furthermore, instead of the line-type inkjet head, a scanning-type inkjet head may be used in which a head unit is mounted on a carriage and forms an image while scanning in a direction perpendicular to the conveyance direction of the sheet material.

[0070] An endless wide belt 62 is provided below the head unit 61, wound around a drive roller 63, a driven roller 64, and a tension roller 65, and is given a predetermined tension so as to move (rotate) in the direction of arrow B. The tension roller 65 is pressed by a compression spring 66, which applies tension to the endless wide belt 62.

[0071] A pinch roller 67 is rotatably provided opposite the drive roller 63 with the endless wide belt 62 interposed therebetween, and applies a pressing force in a direction approaching the drive roller 63 .

[0072] The endless wide belt 62 is also provided with a means for adhering the sheet material S to the belt by air suction or electrostatic adsorption, but these are well known techniques to those skilled in the art and therefore will not be described here.

[0073] According to this image forming apparatus, sheet materials S are sequentially fed from a sheet material feeding section (not shown) and are sent into the discharge device 50 by a pair of conveying rollers 71 from the direction of arrow A in Fig. 12. Then, the sheet material S is conveyed along guide plates 72, 73, between the discharge electrode 52 and the counter electrode 53, to the left in the figure, while being sandwiched between the discharge electrode 52 and the dielectric 54. During this process, the surface of the sheet material S comes into contact with plasma generated by the plasma discharge and is modified, thereby increasing its hydrophilicity.

[0074] When the modified sheet material S comes out of the discharge device 50, it is sandwiched between the endless wide belt 62 supported by the drive roller 63 and the pinch roller 67, adheres to the surface of the endless wide belt 62, and is transported at a constant speed to the image forming position opposite the head unit 61.

[0075] During this time, the head unit 61 drives the inkjet heads 61y, 61m, 61c, and 61k of each color, timing it so that the inkjet heads 61y, 61m, 61c, and 61k are ejected sequentially onto the surface of the sheet S from the nozzles at the tip of each of the inkjet heads 61y, 61m, 61c, and 61k, respectively, as the sheet S is transported in the direction indicated by arrow B, thereby forming a full-color image.

[0076] The printed sheet material on which an image has been formed by the head unit 61 is sent in the direction of arrow C and discharged outside the machine by a pair of conveying rollers (not shown). However, if an image is to be formed on the back side of the printed sheet material as well, the sheet is turned over by a reversing conveying mechanism (not shown) and fed again to the discharge device 50. The discharge device 50 then performs a modification process on the back side of the sheet material before sending it to the image forming section 60, where the head unit 61 forms an image on the back side.

[0077] A post-processing section for applying a coating agent such as varnish may be provided downstream of the image forming section 60 to apply the coating agent to the surface of the printed sheet material. In this case, since the surface of the printed sheet material has already been modified to be hydrophilic, the coating agent can be applied uniformly over the entire surface. This can protect the surface of the sheet material on which the image is formed and add value by giving it a glossy finish.

[0078] Furthermore, in an image forming apparatus equipped with an electrophotographic image forming unit, it is advisable to place the discharge device 50 downstream of the image forming unit and provide a post-treatment unit further downstream for applying a coating agent. This allows the surface of a sheet material onto which a toner image has been transferred and fixed by electrophotography to be modified so that the entire surface is uniformly coated with a coating agent. This is because the water-repellent portions formed on the surface of the sheet material due to the influence of wax contained in the toner particles and silicone oil adhering during fixing can be modified and made hydrophilic by the discharge device 50.

[0079] The discharge device 50 may have a plurality of discharge electrodes 52 arranged in the conveying direction of the sheet material, and the counter electrode 53 and the dielectric 54 configured as flat plates. If the discharge electrode 52 is supported so as to be movable in a direction toward and away from the counter electrode 53 and a pressing force is applied in the approaching direction, the sheet material can be smoothly conveyed regardless of its thickness, and a uniform modification process can be performed.

[0080] The image forming apparatus according to the present invention is not limited to a printer, but may also be a copying machine, a facsimile machine, a digital multifunction machine having multiple functions thereof, a large commercial printer, etc. Furthermore, it is not limited to a device that forms color images, but may also be a device that forms monochrome images, and the sheet material used is not limited to cut sheets, but may also be a long sheet wound in a roll.

[0081] The high-voltage inverter device, discharge device, and image forming apparatus according to the present invention are not limited to the above-described embodiments, and it goes without saying that various modifications, additions, omissions, combinations, etc. are possible.

[0082] (Fifth embodiment) Next, a fifth embodiment will be described.

[0083] The fifth embodiment differs from the first embodiment in that the discharge devices of the first to third embodiments are applied to a plant growing device used in a plant growing method. In the following description of the fifth embodiment, the description of the same parts as the first to third embodiments will be omitted, and only the parts that differ from the first to third embodiments will be described.

[0084] FIG. 13 is a diagram showing an example of a plant growing device used in the plant growing method according to the fifth embodiment.

[0085] The plant growth device of Figure 13 uses the discharge device of the first to third embodiments, and the material of the plant growth container that contains the culture material after voltage application is either silicon or fluorine.

[0086] After the voltage application, the culture material is transferred into a plant growth container for use in growing plants.

[0087] The plant growing container is a container mainly composed of amorphous silicon or fluorine, and seeds can be sown in the culture material contained within the container.

[0088] After voltage application, the air, aqueous solution, or water vapor must be kept in a plant growth container because the generated radical groups and other substances tend to return to their original state. Amorphous silicon, fluorine, and the like are preferred materials for plant growth containers. The inventors tested several container materials and found that containers primarily composed of amorphous silicon or fluorine resulted in 10% faster growth than polypropylene resin. Metal plant growth containers cannot be used because the ions and radical groups in the air, aqueous solution, or water vapor that come into direct contact with the metal surface return to molecules.

[0089] Methods for returning the air, aqueous solution, or water vapor to the plant growth container after voltage application include dissolving the air or water vapor in a solvent in the plant growth container using an air stone, and transferring the culture material to the plant growth container using a circulation system.

[0090] (Sixth embodiment) FIG. 14 is a diagram showing an example of a plant growing device used in the plant growing method of the sixth embodiment.

[0091] The plant growing device of FIG. 14 uses the discharge device of the first to third embodiments, and uses a high-voltage induction coil when applying voltage.

[0092] Culture material 120 is placed in plant growth container 110, and a plant growth area is provided on culture material 120, with the plant growth area filled with gas. An air-core coil 160 made of a conductor with multiple windings of conducting wire and open ends is placed in the plant growth area.

[0093] The air-core coil 160 has a structure in which a conductor having a length of several hundred meters to several kilometers is wound multiple times.

[0094] The oscillator induces a magnetic flux using geomagnetic frequency, thereby inducing a voltage, so that a voltage can be constantly generated around the plant 150. The gas 130 and the culture material 120 can be modified by the voltage. [Explanation of symbols]

[0095] 1 discharge tube 2. Dielectrics 3 Conductive rods 4 conductors 12 Cylinders [Prior art documents] [Patent documents]

[0096] [Patent Document 1] Patent No. 4291320

Claims

1. A discharge device comprising: a hollow cylindrical dielectric of uniform thickness, through which a material to be modified that is to be ionized passes; one or more conductive rods placed parallel to the dielectric inside the dielectric so that a uniform distance from the dielectric is maintained; and a conductor covering the surface of the dielectric; a voltage is applied between the electrically insulating conductive rods and the conductor; the device comprises a plurality of discharge tubes that input and output the material to be modified; and the material to be modified is circulated in multiple stages in sequence within the dielectric of the plurality of discharge tubes; Three or more discharge tubes each having a different number of conductive rods are provided to form three or more electrodes electrically connected in parallel or in series, Between three or more electrodes having different numbers of conductive rods, the air gap length between the dielectric and the conductive rods is kept the same, and the number of the conductive rods is increased in order and the cross-sectional area of ​​the conductive rods is reduced, thereby adjusting the distributed capacitance between the conductive rods and the conductor to be the same. A discharge device characterized by:

2. The electrodes include at least a first electrode, a second electrode, and a third electrode connected in order of the number of conductive rods, The discharge tubes after the second electrode each include a cylinder that is parallel to the conductive rod and has a number of holes to uniformly distribute radicals inside the electrode.

2. The discharge device according to claim 1.

3. The voltage applied between the conductive rod and the conductor is an alternating voltage, and the applied voltage range is automatically adjusted depending on the value of the current that flows when the voltage is applied.

3. The discharge device according to claim 1 or 2.

4. The discharge device according to any one of claims 1 to 3 is provided. A surface modification device characterized by:

5. The discharge device according to any one of claims 1 to 3 is provided. A plant growing device characterized by:

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