JP2010073356A - Ion emission device, and electrostatic charge device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ion emission device for emitting ions stably in a long period without producing discharge products including ozone and NOx, and to provide an electrostatic charge device using the same. <P>SOLUTION: In the positive or negative ion emission device 1, positive or negative DC voltage is applied to a conductive substrate 2 on the surface of which ion emissive material layer 3 containing either a covalent bonding or ion-bonding material is formed, whereby clustered ions generated by the solvation of polar molecules are emitted from the surface of the ion emissive material layer of either the covalent bonding or ion-bonding material on the surface of the conductive substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ion emission device, a charging device, and a charging method, and relates to an ion emission element and a charging device used in an image forming apparatus such as an electrophotographic copying machine, a printer or a facsimile, or an ionizer used in a static eliminator. .

  2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic copying machine or printer, the surface of a photoconductor is uniformly charged by various methods before forming an electrostatic latent image on a charged body called a photoconductor. ing. Further, it is used as an ionizer that is used when static electricity is eliminated by using a similar charging method.

A typical example of a conventional charging method is a corona discharge method. This method is a method in which a corona discharge is applied by applying a voltage exceeding the dielectric breakdown of air from a very thin wire, and this is averaged by a grid to uniformly charge the surface of the photoreceptor. However, since a very large amount of ozone is generated with the discharge from the wire, the organic substance, which is an organic photoreceptor, is not only badly affected by the human body, but also rapidly deteriorates due to the destruction of organic substances that are constituent materials. was there. In order to solve this problem, for example, Patent Document 1 and Patent Document 2 disclose corona chargers that are improved so as to reduce the amount of ozone generated.
In addition to ozone, nitrogen oxide (NOX) can be given as a substance generated by discharge. NOX has a problem that it adsorbs to the surface of the photoreceptor and increases the hygroscopicity of the photoreceptor surface. It is widely known that an electrostatic latent image formed by electric charges is significantly affected by water having conductivity, and therefore causes image quality degradation such as blurring of the image. Similarly, in the ionizer for static elimination using corona discharge, ozone is generated in the same manner, which has a great influence on the deterioration of the object to be neutralized and the health of workers.

  In addition to the image forming apparatus, a contact charging system has been put into practical use in recent years. In this method, in order to reduce the amount of ozone generated and the amount of power consumed, the surface of the photoreceptor is covered with a conductive member such as a conductive roller, a conductive brush, a conductive elastic blade, or a carbon nanotube to which a potential is applied. The surface of the photoreceptor is charged by rubbing and moving the charge.

  As a conductive member, a method using a conductive roller is currently widely used from the viewpoint of charging stability. In the roller charging method, a conductive elastic roller is pressed against a photoconductor, and a DC voltage is applied to the roller to move the electric charge to the photoconductor and charge it to a target surface potential. This method is characterized by relatively low ozone generation. On the other hand, if there are non-uniform defects such as very small pinholes or crystalline substances on the surface of the photoconductor, the surface of the photoconductor can be removed from the conductive roller. A large amount of current flows through the pinholes and defects. As a result, the photoconductor undergoes dielectric breakdown, the conventional performance cannot be maintained, and image formation may be greatly affected.

  As a system obtained by further improving the roller charging system, a system in which a secondary charging roller is added between a primary charging roller and a photosensitive member is known (see Patent Document 3). Here, the secondary charging roller plays a role of transporting charges from the primary charging roller to the photosensitive member, and solves the above-described problem of current leakage due to pinholes and defects of the photosensitive member. However, even in this method, since charging causes a minute discharge between the secondary charging roller and the photosensitive member, ozone and NOX generated during charging have not been completely removed.

  Moreover, what applied the carbon nanotube to the charger is disclosed by patent document 4, patent document 5, etc., for example. In a contact charger using carbon nanotubes, the tube itself is susceptible to physical destruction as it is repeatedly rubbed by the photoconductor, and gradually disappears from the tip when high voltage is applied in the atmosphere. Therefore, there is a fundamental problem that it is not durable enough to be used as an emitter. This is a well-known phenomenon, but even with a relatively low voltage, carbon nanotubes have an extremely concentrated electric field at the tube tip due to its high aspect ratio. In addition, it is said that air ionization accompanying this occurs. Therefore, it can be considered that the tip portion of the carbon nanotube is substantially exposed to a high voltage at all times, and the charge emission portion is severely damaged. In addition, when starting to release charges in the atmosphere, corona discharge may occur, which may cause further damage. The carbon nanotube damaged in this way has a problem that the charge imparting ability is remarkably lowered.

  Patent Document 6 discloses a charging device using the principle of charge electron emission. This is a charging device using an electron-emitting device having a MIS (metal-insulator-semiconductor) structure. This electron-emitting device has a thin film electrode that forms an accelerating field of electrons on the surface side of the porous semiconductor layer. An electrode for injecting electrons into the porous semiconductor layer is provided on the back side of the porous semiconductor layer. In the charging device using this element, negative ions can be generated using only the electron attachment by the electrons emitted from the electron-emitting element, so that no discharge phenomenon occurs. Accordingly, ozone and NOx are not generated in principle as in the above-described method.

  However, in the electron-emitting device using this porous semiconductor layer, electrons accumulated in the nano-sized semiconductor fine particles constituting the porous semiconductor layer due to electron trapping caused particularly during electron emission operation into the atmosphere are porous. There has been a problem that the acceleration of electrons is suppressed by making the electric field inside the crystalline semiconductor non-uniform, and the amount of electron emission is greatly reduced over time. Since the electrons stored in the nano-sized semiconductor fine particles by electron trapping are non-volatile, there are even experimental results that the semiconductor fine particles were charged for more than a week. When such a phenomenon occurs, there is a problem that when the device is driven in the air, the electron emission from the electron-emitting device is completely stopped by the electron trapping even if the device is continuously driven for about 3 minutes.

  As a method for improving long-term emission stability, Patent Document 7 discloses an electron-emitting device in which a linear or branched acyclic hydrocarbon layer having 7 or more carbon atoms is formed on the surface of a porous semiconductor layer. Has been. By providing a layer of an organic compound on the surface of the semiconductor layer, the semiconductor surface was stabilized, and by preventing the adsorption of gas molecules in the atmosphere on the semiconductor surface, it succeeded in suppressing the deterioration of electron emission. Yes. However, although the stability under an argon atmosphere is a very good result, the current fluctuates in a few minutes from the start of release in the atmosphere, and there is still a problem in practical use.

JP-A-9-114192 JP-A-6-324556 JP 2001-296722 A JP 2001-281964 A JP 2008-159431 A JP 2001-331017 A JP 2004-327084 A

  In view of the above circumstances, the main object of the present invention is to provide an ion-emitting device capable of stably discharging ions for a long period of time without generating discharge products such as ozone and NOX, and a charging device using the same. It is to provide.

The above problem is (1) “applying a positive or negative DC voltage to a conductive substrate having a surface formed with a layer of an ion-emitting material containing either a covalent bond or an ion bond material. Thus, cluster ions generated by solvating polar molecules are released from the surface of the ion-emitting material layer of either the covalent bond or the ion-bond material of the conductive substrate surface. Positive or negative ion emitter ",
(2) “Polar molecules are solvated by applying a positive or negative DC voltage to a conductive substrate having a surface on which an ion-emitting material including both covalent bond and ionic bond is formed. A positive or negative ion emitting device characterized in that the cluster ions generated by the above are emitted from the surface of the ion-emitting material layer including both the covalent bond and the ion bond on the surface of the conductive substrate ",
(3) “Ion-emitting device according to item (2), characterized in that an ion-binding material is dispersed in a covalent-bonding material”,
(4) “Includes the ion-emitting device according to any one of (1) to (3)” above and a charged body that is disposed so as to face the element without contacting the element. (5) “The polar molecule is water in the atmosphere, the temperature of the ion emission surface of the ion emission element is set to a dew point temperature or less, and cluster ions are generated by the dew condensation water”. “Charging device according to item (4)”,
(6) This is achieved by “a charging device according to the item (4), wherein polar molecules are supplied in liquid form to the ion emission surface of the ion emission element to generate cluster ions”.

  As will be apparent from the following detailed and specific invention, according to the present invention, an ion-emitting device capable of stably discharging ions for a long period of time without generating discharge products such as ozone and NOX Thus, it is possible to provide a charging device using the same.

  Hereinafter, embodiments of the present invention will be described in detail with examples, but the materials, device configurations, and conditions to be used are not limited thereby. In the drawings of the present specification, the same reference numerals represent the same or corresponding parts.

FIG. 1 schematically shows a typical configuration example of the ion-emitting device of the present invention.
The ion emission element (1) includes a conductive substrate (2) and an ion emission material layer (3) bonded to the conductive substrate (2). When a DC voltage is applied to the conductive substrate by the power source (4), positive ions are emitted from the surface (3) of the ion emission layer when positive voltage and negative ions are applied when negative voltage is applied.

2 and 3 schematically show typical configuration examples of the charging device of the present invention.
The charging device (10) includes an ion-emitting device (1) and a member (11) to be charged that is disposed so as not to contact the ion-emitting device (1). With this configuration, the charged object (11) placed at a position facing the ions emitted from the ion-emitting device by voltage application can effectively receive the discharged ions and charge the charged object (11). it can. Therefore, it is desirable that the member to be charged (11) is connected to the ground to form a closed circuit, but it is not essential to connect to the ground. When the member to be charged is an insulating material such as a polymer, a configuration in which a conductive material (12) is installed on the back side of the member to be charged can be employed as shown in FIG.

For the conductive substrate (2), metals such as Cu, Ni, Ti, Co, Cr, Mo, Nb, Mn, Si, Fe, Al and alloys containing them can be used. Moreover, what carried | supported the metal and the electroconductive substance on the surface, such as glass and ceramics, may be used. Typical examples of the conductive material include metal oxides such as ITO, ZnO, SnO ₂ and TiO ₂ , and carbon compounds such as carbon nanotubes and fullerenes.

  As polar molecules, water, alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol, acetone, ethyl acetate and the like can be used.

  The covalent bond material in the present invention refers to a general material whose chemical bonding mode is exclusively a covalent bond. That is, it is a low molecular organic compound, a high molecular organic compound, or an inorganic compound, and the ion release phenomenon of the present invention can be generated without exception as long as these chemical bonding modes are used. Among the confirmed compounds, particularly representative compounds with a remarkable ion release phenomenon, triphenylamine, long-chain alkyl compounds, low molecular organic compounds, polystyrene, nylon, polyester, polyol, polycarbonate, Examples thereof include fluorine-based resins such as PTFE, silicone resins, and cellulose. Examples of the inorganic compound include boron compounds typified by hexagonal boron nitride, nitrogen compounds, and phosphorus compounds. Any method may be used for layering these materials on the conductive substrate. A method of applying and drying after dissolving in a soluble solvent is simple, but if it is a polymer, it can also be applied by hot melting. In the case of forming a thin film of a low molecular organic compound or an inorganic substance, vapor deposition can be used effectively. The thickness of the layer is not particularly limited as long as the same polarity of charge is induced on the ion emission surface when a DC voltage is applied to the conductive substrate. In the case of an insulating material, if the extra layer is too thick, it is not induced, so it is desirable that the thickness be 100 μm or less, and more preferably 20 μm or less. In the case of a conductive material, there is almost no influence of thickness.

  The ion-bonding material generally indicates a material whose chemical bonding mode is exclusively ionic bonding. That is, inorganic compounds such as silicate glass, alumina, and calcium chloride are exemplified. Among them, the release of ions with a salt structure is remarkable. In this case as well, vapor deposition can be used, and formation of a thin film layer by a sol-gel method is also effective. In the case of a salt soluble in water, it is only necessary to apply it on a conductive substrate after dissolution in water and dry it. In this case as well, the layer thickness is not particularly limited as long as the layer thickness is such that when a DC voltage is applied to the conductive substrate, a charge having the same polarity is induced on the ion emission surface. In the case of an insulating material such as glass, if the layer is too thick, no charge is induced, so it is desirable that the thickness be 30 μm or less, and more preferably 2 μm or less. In the case of an ion conductive material such as a salt, there is almost no influence of the thickness.

  Any method may be used to disperse the ion-binding material in the covalent-bonding material. For example, after the polymer is melted by heat, the ion-binding material is added and kneaded so that the ion-binding material is finely divided. And a method of uniform dispersion is preferred. Alternatively, since the covalent bond material may be a room temperature liquid such as polyvinyl alcohol, the ion bond material may be finely crushed, then dispersed in polyvinyl alcohol, and the dispersion liquid simply applied to the conductive substrate.

  In the present invention, ionization is performed based on a principle completely different from a discharge phenomenon that has been generally known so far. A feature is that ion emission can be performed at a voltage lower than the discharge start voltage based on Paschen's law, whereby the object to be charged can be effectively charged at a low voltage.

  In Paschen's law (hereinafter referred to as Paschen's law), the spark discharge voltage E is proportional to the product of the gas pressure P and the electrode distance d. Paschen's law is an empirical formula showing the voltage at which discharge starts, that is, the voltage at which current clearly flows when parallel plate electrodes are arranged opposite to each other and a uniform electric field is applied. When a voltage is applied between the parallel plate electrodes, if the voltage is increased to the voltage indicated by the Paschen's law, the insulation between the electrodes is broken and the dielectric breakdown of the air occurs, and a spark discharge is observed.

  On the other hand, corotrons and scorotrons using needle-like electrodes and wire-on-wire electrodes create a non-uniform electric field to which locally high electric field strength is applied, and apparently corona discharge is started at a voltage lower than the voltage indicated by Paschen's law. The current at this time is several to several tens of μA or more, and a pulse-like waveform having a sharp peak is seen in the current waveform. Further, light emission called corona occurs around the electrodes. Although the discharge starts apparently at a lower voltage than the Paschen's law, when the Paschen's law is rearranged by the electric field strength, the electric field strength is determined by the constant determined by the gas and the distance between the electrodes, and the corona discharge starting voltage is the spark discharge starting voltage. It will be proportional. In the present invention, the discharge start voltage based on the Paschen's law is used synonymously with the corona discharge start voltage or lower.

  In the case of the present invention, when the applied electric field voltage is extremely low, centering on 0V, there is a threshold value at which the amount of ion emission decreases sharply, and there is a non-charged region where the charged object does not substantially charge. is there. This region can be obtained by the above-described measurement method, and an example of the result of measurement is shown in FIG. Although depending on the material constituting the ion emission surface, ion emission is often not observed up to about 400 V with respect to positive and negative applied voltages. Therefore, in this case, the object to be charged cannot be charged unless it is 400 V or higher. In the present invention, this threshold is called the lowest ion emission potential (V).

  When charging a photoconductor used in an electrophotographic copying machine or printer, it is necessary to control the charging position within the range of 200V to 1200V due to process restrictions. Therefore, it is necessary to use at least between the lowest ion emission potential and the discharge start voltage as a range in which ozone and NOX are not generated and a sufficient charge level is obtained. As a result of repeated experiments, it was found that a range of 30 to 99%, preferably 80 to 95% of the discharge start voltage has a good balance in terms of charging efficiency. If the discharge start voltage is below 1%, ozone and discharge products are below the detection limit, and it is confirmed that almost no generation occurs. In particular, the generation of ozone can be detected as a unique ozone odor even in a very small amount. Moreover, if it is this range, even if it confirms in a complete dark place, the light emission accompanying a corona will not be confirmed at all.

  As an apparatus used as a means for supplying polar molecules, an apparatus that directly supplies the ion emission surface in a liquid state can be used. The liquid may be fed by a pump or the like, or a fine pore may be provided on the ion release surface, or may be supplied from the liquid storage part via a cloth or the like using a capillary phenomenon. Furthermore, liquid supply can also be achieved by atomizing the liquid and spraying or scattering the liquid. Alternatively, the liquid may be heated and evaporated once and then blown to collide with the ion emission surface. In this case, a known humidifier using ultrasonic waves or the like can be used.

  When using a spraying device, it is preferable to attach a sensor capable of measuring the partial pressure of polar molecules. When the polar molecule is water, a humidity sensor can be used, and when the polar molecule is alcohol, an alcohol sensor can be used. Based on the information of these sensors, it is possible to appropriately control the release amount of the polar molecule of the device for applying the polar molecule.

  The proportion of polar molecules in the atmosphere is at least 0.5 vol% or more, preferably 1.0 vol% or more. For example, in the case of water at a temperature of 20 ° C., the relative humidity is preferably 30% or more, preferably 50% or more.

  When the polar molecule is water, humidity (humidity) contained in the atmosphere can be used. In this case, by setting the temperature of the ion emission surface of the ion emission element to be equal to or lower than the dew point temperature, cluster ions can be effectively generated by water condensed on the ion emission surface microscopically. Any cooling method can be used to bring the temperature to the dew point temperature or lower, but it is desirable to use a Peltier element. Since it can be placed in contact with the back side of the conductive substrate, it can be miniaturized when used as a charger. If it is a normal environment, if it is cooled to −10 ° C. to −17 ° C. even during winter drying, sufficient moisture can be secured and extremely stable continuous driving can be achieved.

  Next, operation and operating conditions of the ion-emitting device of the present invention will be shown.

  Here, in the ion emission element (1) shown in FIG. 1, a positive or negative voltage is applied to the conductive substrate (2) by the DC power supply (4). As a result, an electric charge having the same polarity as the applied voltage is excessively present in the conductive substrate (2). Furthermore, since the ion-emitting material layer (3) formed on the conductive substrate (2) is bonded to the conductive substrate (2), the polarity of the applied voltage is also applied to the surface of the emitting material layer. As a result, an electric charge having the same polarity as that is present excessively. This can also be confirmed by observing the surface potential of the ion-emitting material layer (3) in a voltage application state. A positive potential is observed when a positive voltage is applied, and a negative potential is observed when a negative voltage is applied. In this case, all of the excess charges should be ions on the surface of the ion-emitting material layer, but if a large amount of polar molecules are present in the vicinity of the surface of the ion-emitting material layer in this state, the excess ions are encapsulated. As such, polar molecules solvate ions. When the polar molecules are brought into a cluster state in this way, ions are released from the ion-emitting material layer due to Coulomb repulsion, and ions are released.

  Here, in the present invention, the DC voltage may be either positive or negative, and it can be said that the feature is that cluster ions having respective polarities can be generated. In the field electron emission device having the carbon nanotube or the MIS structure, since only electrons can be emitted, it is impossible in principle to emit positive charges. In the case of the present invention, ion emission often starts when the DC voltage is in the vicinity of ± 400 V. This is considered to be because the amount of ion generation increases in proportion to the amount of voltage. In addition, after forming cluster ions, it is necessary to exceed the affinity of the ion-emitting material and to detach from the surface, but since this uses the Coulomb repulsive force with the surface of the ion-emitting layer, there is no charge to some extent. This is thought to be due to the inability to leave.

  In this way, when a positive DC voltage is applied, positive ions are emitted, and when a negative DC voltage is applied, negative ions are emitted from the ion emission surface. FIG. 5 shows the stability of continuous driving when positive ions are released. As long as the polar molecules necessary to form the clusters are supplied, there is almost no fluctuation in current. It is possible to perform very stable ion emission. Similarly, FIG. 6 shows the stability of negative ion continuous drive, but this is also the case. There is no difference due to polarity.

  Here, the principle by which cluster ions are emitted from the ion emitter of the present invention will be described. For simplicity, an example is given in which ions are protons and polar molecules are water.

  A positive voltage applied to the conductive substrate creates a state with excessive positive charge on the conductive substrate. Similarly, a positive charge is induced on the surface of the covalent bond or ionic bond material layered on the surface of the conductive substrate. Although it is difficult to measure what is the positive charge induced on the surface of a covalent or ionic binding material, it would be reasonable to consider it as a positive ion. This is because it cannot be considered that holes are generated on the surface of the covalent bond or ionic bond material.

  Since a strong Coulomb repulsive force acts between the positive ions generated here and the covalently bonded material or ionic bondable material on the conductive substrate, from an energy point of view, the release of ions into the air is an exothermic reaction of several keV. It becomes. The reason why the ions are not released here is that a strong affinity acts between the ions and the covalent bond material or the ion bond material.

  If the induced ion is a proton, an affinity of up to about 8 eV works between this and the covalent material or ionic material, so the charge is not affected by the Coulomb force. Or it will be fixed to the ion binding material. The proton affinity of water molecules is about 7 eV, so proton hydration is endothermic with only one water molecule. However, if additional water molecules are added to this, 1eV if another is added, 0.6eV if another is added, 0.4eV if another is added, and so on, small and highly polar water molecules are added to protons one after another. It can be hydrated exothermically.

  Since the strong affinity of protons depends on the charge delocalization to the additional molecule, the solvation of protons blocks the affinity with charged objects. For this reason, the hydrated proton leaves the charged object and moves to the atmosphere by Coulomb repulsion. In this way, the ionization principle of the present invention is that water molecules wrap up protons and become cluster ions to be released into the atmosphere.

  On the other hand, the phenomenon of the present invention does not occur at all from the metal surface, but since the apparent static dielectric constant of the metal is infinite, it does not cause solvation by water molecules, As a result, it is considered that there is no ion emission.

  The phenomenon of ion release according to the present invention occurs not only with protons but also with negative ions such as hydroxide ions. In addition, polar molecules other than water can be generated in the same manner, and any polar molecule such as alcohol, acetone or ethyl acetate may be used. On the other hand, it has been found that the ion release phenomenon does not occur at all in a nonpolar molecular atmosphere such as benzene and cyclohexane.

  Since the charging device (1) and the electron emission device (10) of the present invention as described above can be driven stably for a long time without generation of ozone and discharge products, the electrophotographic copying machine is particularly suitable. It is suitably used for image forming apparatuses such as printers and facsimiles.

  The ion-emitting device and the charging device using the ion-emitting device of the present invention can also be used in an image forming apparatus using an electrophotographic process. An example is shown in FIG. In addition to the charging device (10) of the present invention, the image forming device (30) includes an exposure unit (irradiating light to the photoreceptor 20 uniformly charged by the charging device to form an electrostatic latent image). 21) Supplying toner (22) to the electrostatic latent image and developing it (23), transferring it to recording paper (24), cleaning for removing the toner remaining on the photoreceptor A part (25), a fixing part (26) of the transferred image, and the like are provided. As the photoconductor (20) that can be charged by the charging device (10) of the present invention, all known photoconductors used in conventional copying machines, printers, and the like can be used. (OPC) and α-Si photoreceptors.

  In addition, since the ion-emitting device of the present invention and the charging device using the same have no generation of ozone, there is no need to consider the influence on the human body even when used in an ionizer used for a static eliminator, etc. Preferably used.

  The embodiments disclosed this time are all examples showing features, and should not be restricted thereby. In addition, since the principle of cluster ion generation is an estimation that can be considered from the data obtained at the present time, the scope of the present invention is shown only by the scope of claims, and is within the meaning and scope equivalent to the scope of claims. All changes in are intended to be included.

(Examples 1-5)
Using the charging device shown in FIG. 3, the distance between the ion release layer (3) and the member to be charged (11) was set to 10 mm. Here, for an experiment for measuring current, the object to be charged was made of conductive brass.
An ammeter was connected in the closed circuit, and the current value was measured. All measurements were performed at atmospheric pressure and temperature in the range of 27 ± 1 ° C. In Examples 1 to 5, polar molecules shown in Table 1 were used. Polar molecules were supplied by spraying polar molecules using an ultrasonic atomizer in an atmosphere with a relative humidity of 13% RH. A brass plate was used as the conductive substrate, and a 5 μm layer of PTFE formed as an ion emission material was used as an ion emission element. A direct current voltage of −1.8 KV was applied to the conductive substrate at a constant voltage, and the current value flowing through the member to be charged (brass) observed after 10 minutes of continuous driving, and the current value after 10 hours were measured. Prior to this, the minimum ion emission voltage is measured. Further, it was determined whether or not ozone odor was generated around the ion release layer after continuous driving for 10 hours. The results are shown in Table 1. In all of Examples 1 to 5, the lowest ion emission voltage was about ± 400V. Further, the current value after 10 hours also decreased within 25% of the current value after 10 minutes.

(Comparative Examples 1-2)
A comparison was performed under the same conditions except that the polar molecule was changed to a nonpolar molecule by the same method as used in Example 1 above. The results are shown in Table 1. In either case of Comparative Examples 1 and 2, no current flowed.

(Examples 6 to 17)
Except that the ion-emitting materials were changed to those shown in Tables 2 and 3, respectively, the same method as used in Example 1 was used. However, here, water is used as the polar molecule. The relative humidity was controlled at 60% using an ultrasonic humidifier. The results are shown in Tables 2 and 3. In the remaining examples, except for Examples 13 and 14, which were approximately doubled, they were around ± 400V. Also in this case, the current value after 10 hours only decreased within 25% of the current value after 10 minutes.

(Comparative Examples 3-4)
A comparison was made under the same conditions except that the ion emitting material was changed to metal by the same method as used in Example 1 described above. The results are shown in Table 2. No current flowed in any of Comparative Examples 3 and 4.

(Examples 20 to 25)
As shown in Table 4, there are two types of ion releasing materials, and the same method as used in Example 1 except that 3 wt% of the ion releasing material (B) is dispersed in the ion emitting material (A). Performed. However, here, water is used as the polar molecule. The relative humidity was controlled at 60% using an ultrasonic humidifier. The results are shown in Table 4. Except for Example 25 exceeding 500V, the remaining Examples were around ± 400V. Also in this case, the current value after 10 hours only decreased within 20% of the current value after 10 minutes.

(Examples 26 to 32)
All the procedures were the same as those used in Example 1, except that the polar molecule liquid supply method was changed as shown in Table 5. However, here, water was used as the polar molecule, and cellulose was used as the ion release material. In Example 26, water was manually supplied using a dropper. In Example 27, this was replaced with a tube pump and automatically supplied. In Example 28, the liquid was supplied from the water reservoir through linen through capillary action. In Example 29, the humidity was controlled to 80% RH with an ultrasonic humidifier. In Example 30, 0.2 cc of water was sprayed onto the ion emission surface every 10 minutes using a spray. In Example 31, the Peltier device was installed on the back side of the conductive substrate, and the temperature of the ion emission surface was set to −10 ° C. In Example 32, the same as Example 31, but the temperature was set to −5 ° C. The results are shown in Table 5. The results are shown in Table 5. In all cases, the minimum ion emission voltage was about ± 400V. Further, the current value after 10 hours also decreased within 25% of the current value after 10 minutes. Example 27 or Example 31 showed excellent stability with no decrease in current value even after 10 hours.

It is a typical conceptual diagram of a preferable example of the ion emission element of the present invention. It is a typical conceptual diagram of the ion emission element and counter electrode which were used in the experiment of this invention. It is a typical conceptual diagram of another form of the ion emission element and counter electrode used in the experiment of this invention. It is the figure which showed the relationship between the applied voltage in the atmospheric pressure of the electron emission apparatus of this invention, and the amount of ion emission currents. It is the figure which showed transition of the positive ion emission current amount with respect to elapsed time when a positive voltage is continuously applied to a conductive substrate. It is the figure which showed transition of the negative ion emission current amount with respect to elapsed time when a positive voltage is continuously applied to a conductive substrate. 1 is a schematic configuration diagram of an example of an image forming apparatus using a charging device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion-emitting element 2 Conductive substrate 3 Ion-emitting material layer 4 DC power supply 10 Charging device 11 Charged body 12 Conductive material 20 Photoconductor 21 Exposure unit 22 Toner 23 Development unit 24 Transfer unit 25 Cleaning unit 26 Fixing unit 30 Image Forming equipment

Claims (6)

  Polar molecules are solvated by applying a positive or negative DC voltage to a conductive substrate having a surface formed with a layer of an ion-emitting material containing either a covalent bond or an ion bond material. The positive or negative ion emitting element characterized in that the generated cluster ions are released from the surface of the ion-emitting material layer of either the covalent bond or ion bond material on the surface of the conductive substrate.   Generated by solvating polar molecules by applying a positive or negative DC voltage to a conductive substrate with an ion-emitting material layered on both surfaces and containing both covalent and ionic bonds. A positive or negative ion emitter, wherein cluster ions are emitted from the surface of the ion-emitting material layer including both the covalent bond and the ion bond on the surface of the conductive substrate.   The ion-emitting device according to claim 2, wherein the ion-bonding material is dispersed in the covalent-bonding material.   A charging device comprising: the ion-emitting device according to any one of claims 1 to 3; and a member to be charged that is opposed to the ion-emitting device without contacting the ion-emitting device.   The charging device according to claim 4, wherein the polar molecule is water in the atmosphere, the temperature of the ion emission surface of the ion emission element is set to a dew point temperature or less, and cluster ions are generated by the condensed water.   The charging device according to claim 4, wherein polar molecules are supplied as a liquid to an ion emission surface of the ion emission element to generate cluster ions.

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