JP2006251618A - Toner separation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner separation apparatus capable of obtaining at least effectively charged toner. <P>SOLUTION: In the toner separation apparatus 1 having a toner leading part 5 to which a charged toner is led and a toner discharge port 6 for discharging the charged toner to an electrostatic latent image holder 200; first electrodes 8 and second electrodes 9 are arranged oppositely to each other in parallel through a space between the toner leading port 5 and the toner discharge port 6, an asymmetrical voltage waveform and a DC voltage waveform are applied to the second electrodes 9, an electric field for discharging charged toner other than the prescribed quantity of charged toner from the space between the electrodes 8, 9 so as not to allow the charged toner to arrive at the toner discharge port 6 is generated between the first electrodes 8 and the second electrodes 9, and an air flow for discharging the excluded charged toner to the outside of the apparatus is formed on the outside of the space between the electrodes 8, 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a developing device used in an electrophotographic image forming apparatus such as a copying machine or a printer. More specifically, the developing device has a desired charge amount at a developing position where an electrostatic latent image is visualized. The present invention relates to a toner separation device that can supply only toner particles.

  In general, in order to obtain a high-quality image by an electrophotographic method, it is extremely important that the toner always has a certain charging characteristic. However, it is very difficult to always give the toner a constant charging characteristic. That is, at present, there are two types of toners, “two-component toner” and “one-component toner”, and charging characteristics have a problem for different reasons.

The former “two-component toner” is a mixture comprising a toner made by mixing and dispersing a colorant in a thermoplastic resin, and a carrier made of fine powdered glass beads or iron powder. It is. Then, the mixed powder is stirred to rub the toner and the carrier so that the toner particles receive a charge having a polarity opposite to that of the electrostatic image charge.
For this reason, in the former, when the mutual friction between the toner and the carrier lasts for a long time, the surface of the carrier is contaminated with the toner composition, and sufficient charge cannot be obtained. There has been a problem that the carrier mixing ratio fluctuates and the charging characteristics of the toner also change.

Further, the latter “one-component toner” is a powder that does not contain a carrier as in the former and consists of only toner. For example, as shown in FIG. 11, the toner T is uniformly and thinly applied to the outer peripheral surface of the toner carrier 91 that is rotationally driven as a rotating body, and the surface of the toner carrier 91 is rubbed by an elastic blade 92 that is fixedly installed. Thus, the toner particles T receive a charge having a polarity opposite to that of the electrostatic image charge. The toner particles T thus frictionally charged adhere to the electrostatic latent image on the electrostatic latent image holding member 200 by electrostatic action.
For this reason, in the latter, another problem has arisen that the charge amount of the toner particles varies depending on the air humidity. That is, when the air is dry, the charge amount is excessive, and conversely when it is wet, the charge amount is insufficient.

  As described above, since the charging characteristics of the toner itself are deteriorated or the charging action is affected by fluctuations in humidity, it is always possible to stably obtain an optimally charged toner for developing an electrostatic latent image. Was difficult. For this reason, there is a problem that the image quality of the image finally output from the image forming apparatus is deteriorated.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the conventional apparatus and to provide a toner separation device that can at least obtain a well charged toner.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a toner introduction port into which charged toner is introduced and the electrostatic latent image holding member, and the electrostatic latent image holding member is charged with the charging member. A toner separation device having a toner discharge port for discharging toner, wherein a first electrode and a second electrode are arranged in parallel and spaced apart from each other in a path from the toner introduction port to the toner discharge port And applying an asymmetric voltage waveform and a DC voltage waveform to the second electrode, and at least charged toner other than a toner having a predetermined charge amount is provided between the first electrode and the second electrode. An electric field to be excluded from between the electrodes was generated so as not to reach the outlet, and an air flow for discharging the excluded charged toner to the outside of the apparatus was formed between the electrodes.

  According to a second aspect of the present invention, in the first aspect, the first electrode is used as a common electrode, and the second electrodes are provided so as to face each other on both surfaces of the first electrode.

  According to a third aspect of the present invention, in the first or second aspect, the first electrode and the second electrode are formed in cylindrical shapes having different diameters and are arranged concentrically.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a plurality of second electrodes are provided, and independent DC voltage generating power sources are respectively provided on the second electrodes, and the second electrodes are provided. A voltage obtained by superimposing a DC voltage waveform and an asymmetric voltage waveform supplied from a DC voltage generating power source for the second electrode is applied to the electrode.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, an opening larger than the particle diameter of the toner is provided in one or both of the first electrode and the second electrode. Or the groove part was provided.

  A sixth aspect of the present invention provides the method according to any one of the first to fifth aspects, further comprising: an air inlet for introducing the air for forming the air flow; and an air outlet for discharging the introduced air. The toner removed outside from the interelectrode region by the action of the electric field generated between the first electrode and the second electrode is discharged together with air from the air discharge port.

  According to a seventh aspect of the present invention, in any one of the first to sixth aspects, a plurality of air inlets and air outlets are provided.

  An eighth aspect of the present invention is the method according to any one of the first to seventh aspects, wherein the surface inside the device is covered with an electret except for an electrode portion.

  According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the toner particles discharged together with air from the air discharge port are returned to the toner charging device and used again.

  According to a tenth aspect of the present invention, in any one of the first to ninth aspects, the toner particles to be reused are discharged by the discharging device before entering the toner charging device.

  The invention according to an eleventh aspect is the structure according to any one of the first to tenth aspects, wherein the structure according to the first aspect is a basic unit and a plurality of basic units are provided.

  Since the present invention is configured as described above, it is possible to provide a small toner separation device that can obtain at least a well-charged toner and can be incorporated in the developing device.

  First, the problems to be solved by the configuration of the present invention are as described above, but further supplemented are as follows.

  In other words, as described above, for “two-component toner” and “one-component toner”, a toner that is always stably and optimally charged for developing an electrostatic latent image can be obtained for each individual reason. In addition to the problem that there is no toner, both types of toner, one-component and two-component toners, are added with a predetermined type of additive, and this additive is adhered to the toner particle surface. There are charge control agents that determine polarity and charge amount, and fluidity imparting agents that prevent toners from sticking together and aggregating. Among these, the additive that has not adhered to the toner particles coagulates, causing a problem of destabilizing the charging of the toner particles.

  In order to cope with these problems, the toner particles and additives have been continuously improved in order to stabilize the charge amount of the toner particles. In addition, a method has been proposed in which after developing an electrostatic latent image, the image density is confirmed by a sensor, the toner charging conditions are controlled, and the toner charge amount is kept constant.

On the other hand, in order to properly control the conditions for charging the toner in real time, it is necessary to know the current charge amount of the toner accurately. The following three methods are known as the main measurement methods for measuring the toner charge amount.
・ Blow-off method ・ E-SPART method ・ Differential electrostatic classification

The blow-off method measures a charge amount of a two-component toner and measures the charge amount of the two-component toner, and the toner is blown off from the carrier to be separated from the electrical neutral condition of the toner before the separation and the carrier. Detect charge.
The E-SPART method is an abbreviation for Electrical Single Particle Aerodynamic Relaxation Time, in which charged particles that vibrate due to sound waves in an electric field are observed with a laser Doppler vibrometer, and the amount of charged particles is determined from the horizontal velocity to the electrode by air The particle size is obtained from the delay in the horizontal speed of the particles due to vibration. That is, as shown in FIG. 8, the measuring device 80 configured using the E-SPART method has an observation box 83 in which openings facing each other as a particle inlet 81 and a particle outlet 82 are formed on the upper and lower surfaces thereof. The electrodes 84 and 84 arranged on the left and right of the observation box 83 and a speaker made of the acoustic vibration plate 85 are installed, and the measurement laser light L passing between the electrodes 84 and 84 is a sensor of the laser Doppler vibrometer 86. The behavior until the toner particles T input from the particle input port 81 are discharged from the particle discharge port 82 under the electric field and sound wave conditions is observed with the laser light L. I am doing so.
As the differential electric mobility measuring instrument, four proposals have been made by RIKEN (for example, JP-A-10-288600, JP-A-10-288601, JP-A-11-264790, JP2000-2000A). -46720.).
A DMA (Differential Mobility Analyzer) is mainly composed of a stainless steel double cylindrical electrode and a Faraday cup electrometer. The electric mobility of the particles is measured by flowing charged fine particles together with the sheath gas from the slits provided in the outer cylinder through the gap between the double cylinders to which a high DC electric field is applied. In the gap, the distance to reach the outer cylinder electrode is determined by the interaction between the charged particles and the sheath gas.

  However, in these three methods, in an electrophotographic image forming apparatus that forms an image using toner such as a copying machine or a printer, the charged state of toner particles used for the image formation is changed during the image forming operation. It was very difficult and practically impossible to know accurately in real time with the built-in device.

First, the blow-off method is not originally developed for on-site measurement. That is, the measurement value cannot be immediately determined at the measurement site where the data is collected, and the measurement target is limited to the two-component toner.
Since the E-SPART method requires a laser beam / speaker / laser Doppler vibrometer, it is complicated and large as a measuring device. That is, it is difficult to store the image forming apparatus in a normal size without changing the size of the apparatus, and it is not practical from the viewpoint of cost.
The differential electrostatic classification method is also not suitable for miniaturization because there are many mechanical parts that require rigidity.
In the conventional measurement method described above, toner particles are collected from the developing device, and the collected toner particles are transported to a measurement device as data to measure the charged state. Eventually, the charged state of the toner actually present in the developing device was measured in real time, and the measurement result could not be reflected and reflected in the operation of the device for charging the toner.

  In addition, based on the ion focusing principle of “High Electric Field Asymmetric Waveform Ion Mobility Spectroscopy”, an apparatus for selectively propagating ions and capturing ions in a three-dimensional space defined by atmospheric pressure is known. (For example, JP-A-2002-522873). However, this device has a curved electrode shape for guiding the flow of gas flow including ions and generating a non-constant electric field, and selectively focuses specific ions to be measured, The density of specific ions is increased, and the quantitative size of specific ions within the measurement sensitivity range is relatively increased to facilitate measurement, and an electrophotographic image forming apparatus, that is, development. It is not a configuration for selecting toner particles used in the developing process of the apparatus.

  In view of this, the present invention sorts charged toner, and supplies the charged toner optimal for visualization of the electrostatic latent image to the electrostatic latent image holding body that holds the electrostatic latent image, that is, a predetermined development position. Thus, a toner separation device that can improve image quality is provided.

  First, “high electric field asymmetric waveform ion mobility spectroscopy” which is a premise of the embodiment of the present invention will be described.

  The phenomenon that forms the basis of this method of measurement was found by E. A. Mason and E. W. McDaniel in the 1960s and was given theoretical support. In summary, ions placed in a high electric field (several tens of kV / cm) under normal pressure show different physical behavior than in a low electric field. In other words, this is due to the fact that the “ion mobility” and “ion diffusion coefficient” representing the properties shared by ion species and neutral gas molecules begin to show anisotropy with respect to the electric field direction. (See EA Mason and Ew McDaniel, “Transport Properties of Ions in Gases”, Wiley, New York [1988] for details.)

  Later, Russia's IA Buryakov et al. Opened the way to application to ion sensors (for details, see IA Buryakov, EV Krylov, EG Nazarov, U. Kh. Rasulev, "A new method of separation of multi-atomic ions by mobility at atmospheric pressure using a high-frequency amplitude-asymmetric strong electric field ", International Journal of Mass Spectrometry and Ion Processes, Volume 128, Issue 3, 9 October 1993, Pages 143-148).

The principle will be briefly described. As shown in FIG. 9A, an RF electric field having an asymmetrical and zero average intensity is applied at right angles to the ion moving direction. At this time, the drift velocity Vy of the ion species in the electric field direction is given by the product of the ion mobility K and the electric field E. That is, the ion mobility in a strong electric field is a function of the electric field, unlike in a weak electric field, so the speed of ion movement differs between when the electric field is strong and when it is weak.
Note that the waveform of the RF electric field where the asymmetrical and average intensity is zero is applied to the electrode in order to form the RF electric field in one period of the waveform, as shown in FIG. 9A. The total sum of products of the voltage and the application time of the voltage is a waveform that becomes zero. That is, the two rectangular regions in the graph indicated by hatching with the symbol β have the same area.

ただし、Ｖｙ：イオン種の進行方向と直交した電界方向へ向うイオン種のドリフト速度
Ｋ(Ｅ)：イオン種に固有な高電界（ＲＦ電界）中におけるイオン移動度Ｋ
Ｅ_ＲＦ：非対称かつ平均強度がゼロのＲＦ電界
Ｅ_ｍａｘ：ＲＦ電界が採る最大電界強度（マイナス値を含む）
Ｅ_ｍｉｎ：ＲＦ電界が採る最小電界強度（マイナス値を含む）
Ｋ_１：Ｅ_ｍａｘ時の係数
Ｋ_２：Ｅ_ｍｉｎ時の係数 For this reason, the drift velocity Vy is given by the following equation.

Where Vy: drift velocity of ion species in the electric field direction orthogonal to the traveling direction of the ion species K (E): ion mobility K in a high electric field (RF electric field) specific to the ion species
E _RF : RF field with asymmetric and zero average strength E _max : Maximum field strength taken by RF field (including negative values)
E _min : Minimum electric field strength (including negative value) taken by the RF electric field
K ₁ : Coefficient at E _max K ₂ : Coefficient at E _min

ただし、α：係数 K (E) in the above formula is represented by the following formula.

Where α is the coefficient

ただし、β：係数 A distance (displacement) ΔyRF in which ions move in the electric field direction during one period is expressed by the following equation.
That is, if one period is from the start time of E _max to the end time of E _min ,

Where β: coefficient

  Therefore, if a DC electric field EC (Compensation field) that cancels this displacement is applied, specific ions behave as if they are not affected by the electric field at all. That is, the ion species can pass through an ion filter using an electric field as a selection means. On the other hand, other ionic species other than this are adsorbed on the electrode and removed by a filter.

FIG. 9B and FIG. 9C simply show the amount of ion displacement when the ions are removed (b) and when the ions pass (c). FIG. 9D shows the concept of operation of the ion filter. That is, as shown in FIG. 9B, other ion species other than the specific ion species accumulate displacement amounts so as to increase monotonously without canceling the offset displacement caused by the action from the DC electric field EC. When reaching the time point t ₁ + t ₂ from the start point at which the effect is applied, the displacement amount is β (K ₁ −K ₂ ), whereas as shown in FIG. The amount of displacement remains zero regardless of the length of the elapsed time for receiving the action. For this reason, as shown in FIG. 9D, a specific ion species maintains a path that can pass between electrodes across an electric field, whereas other ion species other than this specific ion species In this case, the electrode deviates from the above-mentioned course and comes into contact with any electrode that generates an electric field, and is captured by the electrode.

  Some have been put to practical use as a front-end filter for portable gas analyzers and mass spectrometers. The former uses a feature that does not require an evacuation system in the filter (separation part), and aims to detect harmful chemical substances and use it as an air monitor in a spacecraft (Sionex Corporation / USA). The latter has already been put into practical use for the purpose of increasing the sensitivity and resolution of protein mass spectrometry (Ionalytics Corporation / Canada).

  The above is a simple conceptual explanation of the “ion filter” used in “high electric field asymmetric waveform ion mobility spectroscopy”.

Next, an embodiment of the present invention will be described.
That is, in this embodiment, toner particles are used as the ion species in the electrophotographic image forming apparatus, and the principle of the above-mentioned “high electric field asymmetric waveform ion mobility spectroscopy” is applied to the toner particles. In the development step of making the electrostatic latent image of the image formation visible, the toner particles in a predetermined charged state are selected in a predetermined manner, and the selected toner particles are used for the development. I try to improve image quality.

First, as a common premise of the embodiments, a “relationship between the charge amount (Q / m) per unit mass of toner particles with respect to a DC electric field EC (Compensation field)” as shown in FIG. 10 is obtained in advance. . That is, in order to grasp in advance the charging characteristics of the toner used for development by the developing device of the image forming apparatus, the electric field strength of the DC electric field EC and the charge amount per unit mass (Q / m) of the toner The proportional relationship is obtained.
In order to measure the charge amount per unit mass of toner particles (hereinafter referred to as charge mass ratio) that changes in accordance with the electric field strength of the DC electric field EC, the above-described blow-off method, E-SPART method, differential static Any method of electroclassification may be used, and other methods may be used as appropriate.

  Next, a first embodiment of the present invention will be described. As the first embodiment, FIG. 1 shows an example of a toner separating device incorporated in a developing device. That is, as shown in FIG. 1, the developing device 100 is configured such that the toner separating device 1 is provided at the forefront of the path for moving the toner toward the electrostatic latent image holding member 200. That is, the developing device 100 has a toner supplied from a toner replenishing device (not shown) outside the developing device 100 supplied by a toner supplying device (not shown) and travels straight toward the electrostatic latent image holding member 200. The toner charging device 3 and the toner separation device 1 are sequentially arranged.

  The electrostatic latent image holding member 200 forms and holds an electrostatic latent image on the surface thereof, for example, as represented by a photoconductor (OPC: organic photoconductor) having an organic photoconductive layer. The developing device 100 attaches toner as fine powder ink to the electrostatic latent image by an electrostatic action to form a visible image. That is, for example, the photoconductor is a photoconductor drum formed in a cylindrical shape with a predetermined diameter, and at least an organic photoconductive layer is formed on the surface of the drum and is driven to rotate in a predetermined manner. The drum surface is scanned predetermined by a laser beam from an exposure device (not shown) at a predetermined position upstream of the developing position visualized by the toner from 100, and an electrostatic image corresponding to the image to be formed. It is configured to generate a latent image.

  The toner is charged by the toner charging device 3 and introduced into the toner separating device 1. That is, the toner charging device 3 is configured so that at least the charged toner can be continuously fed to the toner separating device 1 without interruption. In addition, the type classified by the toner component may be either “one-component toner” or “two-component toner”. That is, in the case of “two-component toner”, for example, a mesh in which a large number of holes larger than the average particle diameter of the toner particles and smaller than the average particle diameter of the carrier particles are formed is transferred from the toner charging device 3 to the toner separation device. The toner particles are disposed at appropriate positions on the path leading to 1, and only the toner particles are fed to the toner separating device 1 by this mesh, while the carrier particles captured by the mesh are the same as the toner received from the toner replenishing device. Then, it may be configured to return. In addition, the toner charging device 3 charges the toner of the component passing through the toner charging device 3 to a predetermined level, and at least does not decrease the toner passing speed, and the toner separating device without interrupting the toner. As long as the configuration can be fed to 1, an appropriate configuration can be adopted including the conventional configuration shown in FIG.

  The toner separation device 1 includes a toner introduction port 5 connected to the toner charging device 3, a toner discharge port 6 disposed close to the development position on the surface of the electrostatic latent image holding member 200, and both of these ports. And an electric field forming mechanism (not shown) for forming the predetermined electric field between 5 and 6, and the toner particles excluded and excluded from the electric field by the action of the electric field around the electric field. The height of the electrostatic latent image deviating from a substantially linear path from the toner introduction port 5 to the toner discharge port 6 by the action of an air flow, ie, an electric field, which travels in substantially the same direction as the traveling direction of the toner carried on the outside of the apparatus. At least an air flow for discharging toner particles having a charge amount inappropriate for visualizing a high-quality image from the inside of the apparatus is formed. Note that an air generation source for supply or scavenging such as an air pump (not shown) is provided in the developing device 100 itself or in the vicinity of the developing device 100, and air of a predetermined pressure is supplied from the air generation source to the separation device. Alternatively, the air in the separation device is drawn into the air generation source side to form the air flow in the toner separation device 1.

  The toner particles given a predetermined charge by the toner charging device 3 are guided to the toner introduction port 5 of the toner separating device 1. The toner separating apparatus 1 sets in advance toner that can pass through the apparatus toward the electrostatic latent image holding member 200 based on a charge mass ratio (Q / m). Specifically, the DC bias voltage value superimposed on the asymmetric voltage waveform is adjusted appropriately. More specifically, in accordance with the charge-mass ratio as a characteristic of the toner obtained in advance, a charged toner that is optimal for visualizing an electrostatic latent image with high image quality can be obtained under almost normal atmospheric pressure conditions. The DC bias voltage value is set so that the electric field can be formed by proceeding in the passing direction as it is and proceeding straight.

  Therefore, toner particles having an optimum charge amount for visualizing the electrostatic latent image with high image quality are discharged from the toner discharge port 6 toward the electrostatic latent image holding member 200. That is, toner particles having an optimum charge amount are selected from the toner charged and supplied from the toner charging device 3, and the selected toner particles are applied to the surface of the electrostatic latent image holding member 200. It is injected so that it may face up. For this reason, the toner particles are accurately and reliably applied to the electrostatic latent image on the surface that moves as the electrostatic latent image holding member 200 rotates by electrostatic attraction acting between different kinds of charges. In this state, the electrostatic latent image is visualized with a high quality image.

  As described above, according to the toner separation device of the first embodiment, a high-quality toner visible image can be obtained, and the image quality can be improved. That is, in the developing device, the toner separation device provided between the toner charging device and the electrostatic latent image holding member separates the toner particles having an inappropriate charge amount that deteriorates the image quality from the toner particles having an appropriate charge amount. Thus, since the electrostatic latent image can be excluded from the developing process for visualizing with toner, only toner particles having an appropriate charge amount can be used in the developing process, and at least the toner particles thus selected can be used. The image quality of the electrostatic latent image to be visualized can be improved. As a result, the quality of the finally output image can be improved.

  In addition, this toner separation device performs a predetermined toner separation operation by the electric action of an electric field, and a predetermined air flow is formed inside the device by air supplied from outside the device. Therefore, the movable member driven by the motor can be eliminated. Therefore, this also makes it possible to sufficiently pursue downsizing. On the other hand, the toner separation device does not include at least a vibration generation source caused by a mechanical movable member. Therefore, it is not necessary to vibrate the toner discharge port itself, and naturally, it is not necessary to newly vibrate the electrostatic latent image holding member due to a factor on the separation device side, that is, the development device side. As a result, a high quality image obtained by visualizing the electrostatic latent image can be obtained.

  Next explained is the second embodiment of the invention. In the second embodiment, a specific configuration of the electric field forming mechanism of the first embodiment is defined. In addition, the same code | symbol is attached | subjected to the same component as said 1st Embodiment, and description is abbreviate | omitted or simplified. That is, although not particularly described, the configuration not described in the second embodiment, that is, the configuration of the electrostatic latent image holding member is the same as that of the first embodiment.

  As shown in FIGS. 2A and 2B, the toner separation device 1 according to the second embodiment forms a substantially linear path from the toner introduction port 5 to the toner discharge port 6 therein. In order to generate the above-described electric field continuous in a longitudinal direction in the longitudinal direction of the path in the apparatus main body 7, a predetermined inter-electrode distance is secured, and a first space is separated from each other in a substantially vertical direction. The electrode 8 and the second electrode 9 are arranged opposite to each other in parallel, and a predetermined length is continuously secured along the longitudinal direction of the path.

  The apparatus main body 7 has a predetermined rectangular sealed space formed therein as a substantially linear path, and accommodates the first electrode 8 and the second electrode 9, and includes an inside of the apparatus main body 7. A toner inlet 5, a toner outlet 6, an air inlet 10, and an air outlet 11 are opened at predetermined locations on the wall. That is, the apparatus main body 7 is installed in such a direction that the center line in the longitudinal direction coincides with at least a line connecting the toner charging device 3 and the electrostatic latent image holding body 200 linearly.

  The first electrode 8 and the second electrode 9 are formed in a substantially flat plate shape using a predetermined conductive material, with a predetermined distance in the vertical direction and parallel to each other across the center line of the path. It is fixed in a state of being insulated from other constituent members in the apparatus main body 7 by a fixing member such as an insulating material (not shown), the outer surfaces of the first electrode 8 and the second electrode 9, and the aforementioned Between the inner wall surface of the apparatus main body 7 that forms the path, a gap for allowing the air flow for discharging the excluded toner particles to the outside of the toner separating apparatus 1 is secured. The length in the longitudinal direction of the apparatus body 7 that forms the path, that is, the lengths of the first electrode 8 and the second electrode 9 is determined by the action of the electric field generated between the electrodes 8 and 9. The length of the toner particles can be surely excluded from between the electrodes. That is, as a length from the start end to the end end of the electric field defined by the length as viewed from the toner particles entering the electric field, a time for the toner particles to be sufficiently separated from the electric field is secured. The set length is set.

  The toner discharge port 6 is formed in a tapered nozzle shape whose cross-section continuously decreases as it advances toward the tip side at least in the longitudinal cross-sectional shape thereof, and the toner discharge port 6 of the first embodiment described above. Similarly, the opening at the tip of the nozzle is close to and directly facing the surface of the electrostatic latent image holding member 200, and the toner discharged from the tip of the nozzle is in contact with the surface of the electrostatic latent image holding member 200. The development position on the surface of the electrostatic latent image holding member 200 is set to a predetermined value.

  In addition, the length in the width direction in the cross section of the path in the apparatus main body 7 shown in the left-right direction in FIG. 2B is at least as long as the length of the electrostatic latent image holding body 200 in the axial longitudinal direction. The toner that is secured and discharged from the toner discharge port 6 connected to the path can cover the electrostatic latent image generated on the surface of the electrostatic latent image holding member 200.

  An air introduction port 10 through which air is introduced from the outside of the apparatus main body 7 is formed in the vicinity of the toner introduction port 5 in the apparatus main body 7 that forms the above-described path, while the vicinity of the toner discharge port 6 in the apparatus main body 7 is formed. Is formed with an air outlet 11 for discharging the introduced air. That is, at least one pair of air introduction ports 10 is provided in an axially symmetric position around the line connecting the toner introduction port 5 and the toner discharge port 6 in the vicinity of the toner introduction port 5. These air inlets 10 have the same opening cross-sectional area. Similarly, at least a pair of air discharge ports 11 are provided in the vicinity of the toner discharge port 6 and centered on the connected line, and are opened at positions that are axially symmetric. 11 has the same opening cross-sectional area.

  Either of the air inlet 10 or the air outlet 11 is connected to a predetermined air generation source similar to that of the first embodiment, thereby generating the air flow. ing. That is, for example, is the air introduction port 10 connected to an air supply source for air supply via a tube or the like forming an air flow path, and is air supplied at a predetermined pressure and a predetermined flow rate at the air introduction port 10 being supplied? The air discharge port 11 is connected to a scavenging air generation source via the same tube or the like, and air having a predetermined pressure and a predetermined flow rate is discharged from the air discharge port 11.

  Therefore, air is introduced into the apparatus main body 7 from the air introduction ports 10 at an equal flow rate, and the introduced air is discharged from the air discharge ports 11 to the outside of the apparatus main body 7 at an equal flow rate. Is done. Therefore, the air flow from the toner introduction port 5 to the toner discharge port 6 on the connected line and in the vicinity of the line formed along with the air flow is formed on the connected line. As long as it is located in the vicinity of the line, it reaches the toner discharge port 6 and is discharged from the toner discharge port 6. That is, the charged toner particles introduced from the toner introduction port 5 are discharged as they are from the toner discharge port 6 as long as they are located on the connected line and in the vicinity of the line. Then, the first electrode 8 and the second electrode 9 are disposed so as to surround the connected line and the vicinity of the line, and an electric field is formed on the connected line and the vicinity of the line.

  That is, the first electrode 8 is grounded by a predetermined wiring connection, while the second electrode 9 is variable with an asymmetric voltage waveform generating power source 12 that generates an asymmetric voltage waveform by a predetermined wiring connection. A DC voltage generating power source 13 that generates a DC voltage waveform of the voltage is connected in series.

  Therefore, in the toner separation device 1 configured as described above, the toner particles that have entered the toner separation device 1 from the toner introduction port 5 together with the air flow created by the air that is forcibly taken in from the air introduction port 10 are first. To the gap between the electrode 8 and the second electrode 9. That is, the charged toner particles enter between the electrodes 8 and 9 in such a direction that they pass at least between the first electrode 8 and the second electrode 9 and can reach the toner discharge port 6. As long as no external force is applied, the vehicle advances in the direction of the direction. Between the electrodes 8 and 9, a voltage is applied by superimposing an asymmetric waveform as shown in FIG. 13 and a DC waveform, and a predetermined electric field is generated.

  Then, while the charged toner particles move between the electrodes toward the downstream toner discharge port 6 in parallel with the electrodes, the toner whose displacement amount reaches the distance between the electrodes due to the action of an electric field during the forward movement. The particles adhere to the electrode or jump out of the electrode and are removed. Only toner particles whose displacement amount has not reached the distance between the electrodes are discharged from the toner discharge port 6 toward the electrostatic latent image holding member 200. On the other hand, the toner particles excluded outside the electrode are discharged from the air discharge port 11 together with the air flow.

  As the voltage condition applied to the electrodes, an optimum condition is selected according to the distance between the electrodes and the air flow rate. For example, when the distance between the electrodes is 1 cm, a power source capable of generating a maximum amplitude of 2 kV of the asymmetric applied voltage at a frequency of 1 MHz and a DC power source of up to 200 V are prepared. Thus, the charged toner particles passing through the electric field can be separated in a predetermined manner under atmospheric pressure based on the charge amount as the electric mobility inherent in the particles. That is, the charged toner that passes through the toner separation device 1 can be arbitrarily selected by adjusting the DC bias voltage.

  Further, an opening 14 or a groove is formed as a through hole penetrating in the thickness direction of the first electrode 8 or the second electrode 9 or both. That is, in the electrode, there are formed a large number of through holes from the inner surface facing the formed electric field to the outer surface facing the air flow so as not to weaken the electric field forming effect. The structure is an opening having an opening cross-sectional area sufficiently larger than the particle diameter of the toner, a groove, or a mesh electrode member.

  That is, the adsorption of toner particles to the electrode is not preferable in terms of maintenance and management of the separation device, and therefore many fine holes are made in the electrode or a mesh electrode is often used. If the hole size is made larger than the toner particle size, the toner particles inappropriate in the development process in which the displacement due to the electric field action has reached the distance between the electrodes will not be adsorbed by the electrodes and will pass through the holes. As a result, the airflow is quickly taken out of the electrode and discharged along with the airflow from the air discharge port 11 to the outside of the toner separation device 1.

  As described above, according to the toner separation device of the second embodiment, the same effects as those of the first embodiment described above can be obtained.

  The toner particles discharged together with the air outside the electrode may be circulated again to the charging device. That is, the excluded toner particles may be charged again and used in the development process.

  Next explained is the third embodiment of the invention. That is, in the second embodiment, in order to form a predetermined electric field, a predetermined inter-electrode distance is provided, and the first electrode and the second electrode are arranged to face each other in a substantially vertical direction. In contrast, in the third embodiment, a cylindrical first electrode and a second electrode having different diameters are arranged concentrically. In addition, the same code | symbol is attached | subjected to the same structural member as said 1st, 2nd embodiment, and description is abbreviate | omitted or simplified. That is, although not particularly described, the configuration that is not described in the third embodiment, that is, the configuration of the electrostatic latent image holding member, and the like are the same as those of the first and second embodiments.

  As shown in FIG. 3, in the toner separation device 20 of the third embodiment, the first electrode 8A and the second electrode 9A are made of cylindrical materials having predetermined diameters different from each other using a conductive material. The two cylindrical electrodes 8A and 9A are concentrically centered on the center line of this path at least in a linear path toward the electrostatic latent image holding body 200 in the apparatus main body 3 described above. It is set as the arrangement arranged in.

  That is, the first electrode 8A and the second electrode 9A have the same length in the axial longitudinal direction and are larger than the outer diameter of the first electrode 8A formed in a cylindrical shape with a predetermined diameter. The second electrode 9A is formed in a cylindrical shape with a predetermined large inner diameter, and the second electrode 9A is disposed concentrically around the first electrode 8A. Accordingly, the first electrode 8A and the second electrode 9A are arranged to face each other with a space equidistant from each other in the substantially radial direction, and the electric field is generated between the electrodes 8A and 9A. .

  That is, a predetermined inter-electrode distance similar to that in the second embodiment described above is uniformly between the outer peripheral surface of the first electrode 8A and the inner peripheral surface of the second electrode 9A. In the same manner as in the second embodiment described above, the first electrode 8A is connected by wiring so as to electrically ground the first electrode 8A. The second electrode 9A is connected in series to a power source 12 that generates an asymmetric voltage waveform and a power source 13 that generates a DC voltage waveform of a variable voltage. Accordingly, a voltage in which two predetermined waveforms are superimposed is applied to the second electrode 9A as in the second embodiment, and the electric field is generated in the ring-shaped gap. The first electrode 8A and the second electrode 9A are preferably cylindrical mesh electrodes, but may naturally be electrodes having the above-described openings or grooves. In addition, the device body 7 surrounding the second electrode 9A having a large outer diameter has at least a portion facing the second electrode 9A similarly securing a predetermined gap with the outer peripheral surface of the second electrode 9A. It is formed in the shape of a concentric cylinder.

  In the apparatus main body 7, a toner introduction port 5 (not shown) that supplies charged toner from the toner charging device 3 to the gap between the electrodes, and charged toner that has passed through the gap in a predetermined manner are transferred to the electrostatic latent image holding member. A toner discharge port 6 (not shown) that discharges to 200 is provided. That is, the toner to which the charged toner is supplied in the two ring-shaped openings opened at both ends of the double cylinder arranged in this manner in the apparatus main body 7 so as to face one of the openings on the charging device side. An introduction port 5 is provided, and a toner discharge port 6 is provided facing the other opening on the electrostatic latent image holding body 200 side. Note that a plurality of toner introduction ports 5 or toner discharge ports 6 may be provided intermittently along the ring-shaped opening, or one may be provided in a ring-shaped continuous opening shape. As long as the charged toner can be introduced from one side of the gap and discharged from the other side, they may be combined as appropriate.

  Also, air inlets and air outlets for air (not shown) are respectively provided on the outer side and the inner side of the double electrode cylinder. That is, the toner particles excluded by the air flow sent from the air inlet port to the air outlet port from between the electrodes to the inside of the first electrode 8A or the outside of the second electrode 9A due to the action of the electric field, It is configured to be carried away. As with the toner introduction port 5 and the toner discharge port 6, both the air introduction port and the air discharge port may be provided intermittently or may be provided in a ring-like continuous opening shape. Good.

  Therefore, in the toner separation device 20 configured as described above, the toner particles to be separated, which are charged and introduced into the toner separation device, are applied to the two cylinders and generated in the gap between the two cylinders. In the process of passing through, a predetermined separation and selection are performed in the same manner as described above by the action of the electric field.

  As described above, according to the toner separation device of the third embodiment, the same effects as those of the first embodiment described above can be obtained.

  On the other hand, in the toner separation device of the third embodiment, at least the cross-sectional shape in the vicinity of the electrode can be a circular shape, so that the pressure resistance performance can be improved. That is, the flow rate of air passing through the toner separation device can be increased, and the flow rate of toner can be increased accordingly. For this reason, as a toner separation device, it is possible to increase the sorting processing capability. As a result, the development processing capability of the developing device using the toner separation device can be increased, and the development performance can be improved.

  Next explained is the fourth embodiment of the invention. That is, in the above fourth embodiment, in order to form a predetermined electric field, a predetermined inter-electrode distance is provided in a substantially vertical direction, and the first electrode and the second electrode are provided in one path. In contrast to the opposed arrangement, in the fifth embodiment, the first electrode and the second electrode are arranged in a plurality of paths divided and divided by partition walls, and For each path, the bias voltage application condition by each DC power supply can be set to a predetermined value. In addition, the same code | symbol is attached | subjected to the same structural member as said 1st, 2nd embodiment, and description is abbreviate | omitted or simplified. That is, although not particularly described, the configuration not described in the fourth embodiment, that is, the configuration of the electrostatic latent image holding member, and the like are the same as those in the first embodiment and the second embodiment.

  As a fourth embodiment, an example of a toner separation device having a plurality of independent DC power supplies and second electrodes is shown in FIGS. 4 (a) and 4 (b). That is, the toner separation device 30 of the fourth embodiment is provided with a plurality of electrode pairs each including the first electrode 8a and the second electrode 9a independently as an electrical configuration, A plurality of DC voltage generating power sources 13a for individually superposing dedicated DC voltages are provided on the second electrodes 9a of each set.

  As shown in FIGS. 4A and 4B, the toner separation device 30 has a path formed in the apparatus body 7 parallel to the longitudinal direction of the path, and the width direction of the path. The four partitions are divided into four paths by three partition walls 31 spaced apart at equal intervals, and each of these four paths has a pair of first electrode 8a and second electrode 9a. These electrodes are arranged in a predetermined manner and connected to each other in a predetermined manner so that an electric field in which individual DC bias voltage conditions are set independently can be generated in each path.

  Each first electrode 8a is configured such that a plurality of wirings connected to each first electrode 8a are gathered together and grounded in common, whereas each first electrode 8a One asymmetric voltage generation power source 12 for applying a common asymmetric waveform voltage to each of the second electrodes 9a is installed, and a branch is connected from the asymmetric voltage generation power source, and wiring is connected. Are connected in series on a plurality of wires branched for each of the second electrodes 9a, and independent DC voltage generating power supplies 13a, 13a are installed for each of the second electrodes 9. The generation power supply 13a is configured to be capable of setting individual DC voltage output conditions independently of each other.

  In the toner separation device of the fourth embodiment, the so-called device main body 7 of the second embodiment and each member provided in the device main body 7 are narrowed to a predetermined width, and the horizontal width is set to a predetermined value. A plurality of narrowed apparatus main bodies 7 are arranged in parallel in the longitudinal direction of the axis of the electrostatic latent image holding body 200. In other words, the apparatus main body 7 of the second embodiment is made into one basic unit, and a plurality of basic units are linearly made to be opposed to each other in the axial longitudinal direction on the outer peripheral surface of the electrostatic latent image holding body 200. The arrangement is such that the toner discharge ports 6 of the respective basic units are aligned.

  Therefore, a bias voltage from a different DC power source and a common asymmetric waveform voltage are superimposed and applied to each second electrode 9a. The pair of the first electrode 8a and the second electrode 9a in different bias states are separated from each other by a partition wall. In this way, the electric fields generated by the pair of first electrodes 8a and second electrodes 9a installed in the paths partitioned by the partition walls do not need to interfere electrically with each other.

  By adopting such a structure, toner particles having different electric mobilities can be simultaneously obtained without imprinting a DC bias voltage.

  That is, the potential of the electrostatic latent image holding member 200 often has a non-uniform distribution in the main scanning direction. For example, when the electrostatic latent image holding member 200 is a photosensitive drum, the drum longitudinal axis direction on the drum surface of the photosensitive drum is the main scanning direction, and a uniform potential distribution is present throughout the main scanning direction. There is little to be obtained. This greatly affects the quality of the image obtained by visualization. In other words, the image quality of the visible image may deteriorate due to the influence of the non-uniform potential distribution.

  On the other hand, in the above fourth embodiment, the DC bias voltage is set individually for each path independently without interfering with each other so as to suppress such image quality deterioration during development. Therefore, it can be set to a predetermined value so as not to affect the quality of the image obtained by the above visualization. That is, for example, in a certain electrostatic latent image, when a region having a potential distribution higher or lower than usual is generated locally in the electrostatic latent image, it can be detected and predicted in an initial stage or a middle stage of a series of image forming processes. In this case, only the electric field of the path facing the area among the plurality of paths is reset to a predetermined value, and the charged toner charged by the charging device is charged as optimal as possible to visualize the area. The toner particles in a state can be selected and obtained.

  As described above, according to the toner separation device of the fourth embodiment, even if a non-uniform potential distribution is generated in the main scanning direction of the electrostatic latent image holding member, a predetermined amount corresponding to this is previously determined. For each of the plurality of subdivided paths, the non-uniform potential distribution can be set so as not to affect visualization. For this reason, it is possible to sufficiently suppress the deterioration of the image quality of the image obtained by visualizing the electrostatic latent image having a non-uniform potential distribution. As described above, since it is possible to deal with electrostatic latent images having various potential distribution states, not only the image forming ability by the developing process but also the image forming ability of the entire image forming apparatus can be enhanced.

  In the toner separation device, the divided paths, that is, the toner discharge ports 6 are arranged in a horizontal row along the axial longitudinal direction of the electrostatic latent image holding member. It may be provided in multiple stages. That is, a configuration in which the electrostatic latent image holding member is arranged in multiple rows such as two rows along the rotation direction of the electrostatic latent image holding member may be adopted. In this configuration, the total amount of charged toner necessary for making the electrostatic latent image visible Is substantially constant, the number of paths, that is, the number of toner discharge ports can be increased, so that the flow rate of charged toner passing through each path can be reduced. For this reason, the accuracy and precision of the sorting ability by the electric field can be improved, and stable sorting becomes possible.

  Next explained is the fifth embodiment of the invention. That is, in the above fourth embodiment, in order to form a predetermined electric field, a predetermined distance between the electrodes is provided in a substantially vertical direction, and a pair of the first electrode and the second electrode are provided in one path. In the fifth embodiment, two second electrodes are arranged opposite to one first electrode, that is, above and below the first electrode. The second electrode is arranged so as to face both surfaces. In addition, the same code | symbol is attached | subjected to the same structural member as said 1st, 2nd, 4th embodiment, and description is abbreviate | omitted or simplified. That is, although not particularly described, the configuration that is not described in the fifth embodiment, that is, the configuration of the electrostatic latent image holder is the same as that of the first embodiment, the second embodiment, and the fourth embodiment. Has been.

  As shown in FIG. 5, the fifth embodiment is a toner separation device 40 having a plurality of independent DC power supplies and second electrodes 9a, and in particular in the case of this configuration, The electrodes 9a and 9b are provided on both sides of the first electrode 8a.

  That is, in the vertical direction in FIG. 5, the first electrode 8a of the long plate electrode is disposed as a common electrode at a substantially central portion of the path, and a predetermined distance between the electrodes is higher than the first electrode 8a. The second electrode 9a, which is a long plate-like electrode, is disposed in parallel while securing a distance, and a predetermined inter-electrode distance is secured below the first electrode 8a, and the second electrode 9b is Arranged in parallel, a gap is formed between the second electrode 9a and the path to allow a discharge air flow to flow in a predetermined manner. And while connecting the first electrode 8a to be grounded in common, the two second electrodes 9a and 9b arranged in each path are similar to the fourth embodiment, Wiring is connected so that a bias voltage by a DC power supply and a common asymmetric waveform voltage are superimposed and applied. In the toner separation device 40 of the fifth embodiment, a superimposed voltage is applied to one second electrode 9a via a wiring, and the second electrode 9a is applied to the second electrode 9b via the wiring. Although the configuration is such that the superimposed voltage is applied, it may be reversed, and further, the wiring connected to the second electrode 9a and the second electrode 9b may be branched.

  Therefore, according to the toner separation device 40 configured as described above, the amount of charged toner passing through the device can be increased. That is, two electric field regions for sorting charged toner can be generated by one first electrode 8a, and the amount of charged toner that can be separated and sorted per unit time as the toner separating device 40 is doubled. it can. For this reason, the amount of toner that is sorted and released to the electrostatic latent image holding member 200 increases, so that the development processing time can be further shortened.

  As described above, according to the toner separation device of the fifth embodiment, in addition to the same effect as the effect of the fourth embodiment described above, the toner separation device can increase the sorting processing capability. Therefore, the development processing capability of the developing device using the toner separation device can be enhanced, and the development performance can be improved.

  On the other hand, as described above, since two electric field regions can be generated in the separation device that are opposed to both surfaces of one first electrode, the space utilization efficiency in the separation device can be improved. For this reason, the separation device can be made compact. As a result, it is possible to widen the selection range of the developing device to be installed with this separation device, and to obtain a wide application range.

  Although the fifth embodiment is applied to the configuration of linear electrodes arranged in parallel at a predetermined distance, the configuration of the cylindrical electrode similar to that of the third embodiment is not limited to this. You may apply to. That is, the second electrodes are arranged concentrically on the outer side and the inner side of the first electrode in the third embodiment, respectively, and are connected to predetermined wirings. It is good also as a structure which has arrange | positioned the entrance and exit of this. More specifically, as a configuration in which three cylindrical electrodes are arranged concentrically, a predetermined second gap distance is secured on the outer peripheral surface of the first electrode, and the second cylindrical shape facing the inner peripheral surface thereof. A configuration of a triple cylindrical electrode in which an electrode is provided, a predetermined gap distance is secured on the inner peripheral surface of the first electrode, and a cylindrical second electrode facing the outer peripheral surface may be provided.

  Next, a sixth embodiment of the present invention will be described. That is, in the above second embodiment, in order to form a predetermined electric field, a predetermined inter-electrode distance is provided in a substantially vertical direction, and the first electrode and the second electrode are opposed to each other in one path. In addition to the arranged configuration, in the sixth embodiment, the surface inside the device other than the surfaces of the first electrode and the second electrode facing the toner passing through the toner separating device, The electret has a charge opposite to that of the toner particles. In addition, the same code | symbol is attached | subjected to the same structural member as said 1st, 2nd embodiment, and description is abbreviate | omitted or simplified. That is, although not particularly described, the configuration that is not described in the sixth embodiment, that is, the configuration of the electrostatic latent image holder is the same as that in the first and second embodiments.

  As shown in FIG. 6, the toner separation device 50 of the sixth embodiment covers the surface inside the toner separation device 50 with an electret 51 except for the electrode portion. That is, the apparatus main body of the toner separating apparatus 50 has at least the surface of a component member that is likely to contact the toner passing through the apparatus other than the electrode portion of the apparatus main body, that is, the surface inside the apparatus main body other than the electrode surface. Is covered with an electret 51 having a charge opposite to that of the toner particles.

  The electret 51 means a dielectric material in a semi-permanent charged state, and an ordinary insulator generates dielectric polarization only when the charged body is near, and this polarization is generated when the charged body is moved away. However, the electret 51 is an insulator that keeps permanent polarization regardless of the presence or absence of a charged body. As the electret 51, an appropriate electret material may be used. For example, an electret material obtained by applying an electric field to a predetermined polymer material may be used.

  Therefore, the toner particles can be prevented from staying unnecessarily in the toner separation device 50. That is, the toner particles before separation, the toner particles excluded by the electric field applied between the electrodes, the toner particles finally selected after passing through the separation device, and these charged particles are brought into the toner separation device by electrostatic force. When the toner adheres, various problems such as clogging of the toner introduction port 5 and the toner discharge port 6 or a decrease in separation function due to adhesion of the excluded particles to the tube wall occur. As shown in this example, by covering the inner surface of the separation device with an electret 51 having a charge opposite to that of the toner particles, such a problem can be greatly reduced. That is, it is possible to eliminate the adhesion of the toner particles to the electret 51, that is, the inner surface by generating an electrostatic repulsive force between the electret 51 covering these surfaces and the toner particles.

  As described above, according to the toner separation device of the sixth embodiment, at least a surface other than the electrode portion of the toner separation device that is likely to contact the toner passing through the device, that is, a toner other than the electrode surface. Since the surfaces inside the separation device are covered with electrets having a charge opposite to that of the toner particles, it is possible to prevent the toner particles from adhering to these surfaces. For this reason, in the toner separation device, the toner introduction port 5 and the toner discharge port 6 are clogged by the toner particles before and after the separation, or the separation function is deteriorated due to the excluded particles adhering to the inner wall of the separation device. Problems can be prevented beforehand.

In each of the embodiments described above, naturally, an appropriate portion of the inner surface may be covered with an electret.
In the sixth embodiment, the predetermined surface is covered with the electret as another member. However, the present invention is not limited to this, and ion polarization and electronic polarization are fixed to the member formed with the above surface. If the electret material is uniformly dispersed and embedded, or the electret material is embedded locally, and at least the above-mentioned repulsive force can be electrically generated on the surface of the member, it is integrated with the member. These components may be included as a covered structure, or may be a locally provided structure of the member.

  Next, a seventh embodiment of the present invention will be described. That is, in each of the above embodiments, the toner excluded from the development process is discharged to the outside of the apparatus. In the seventh embodiment, the excluded toner is discharged and reused. Yes. In addition, the same code | symbol is attached | subjected to the same structural member as said 1st, 2nd embodiment, and description is abbreviate | omitted or simplified. That is, although not specifically described, the configuration that is not described in the seventh embodiment, that is, the configuration of the electrostatic latent image holder is the same as that in the first and second embodiments.

  In the seventh embodiment, as shown in FIG. 7, the excluded toner is collected and returned to the toner charging device 3 and reused in the developing process as an associated configuration related to the toner separating device 60. In addition, a toner neutralizing device 61 that neutralizes charged toner is provided in the middle of the toner recycling process. As the configuration of the toner separation device 60, any one of the configurations in the second to sixth embodiments described above is adopted as appropriate.

  Specifically, the developing device 100 includes a path for returning the toner discharged from the toner separating apparatus 60 to the toner charging apparatus, and a toner discharging device 61 disposed at an appropriate position in the middle of the path. Before the toner is returned to the toner charging device 3 by the toner discharging device 61, the charged state of the toner is released.

  That is, the return path is formed in a tubular shape, and one end thereof is connected to the above-described air discharge port (not shown) of the toner separation device 61, or when there are a plurality of the air discharge ports, one end of each is connected. However, the other end is connected to the toner charging device 3 via the toner discharging device 61.

  The toner neutralizing device 61 is installed in the middle of a path for returning the toner excluded by the toner separating device 60 to the toner charging device 3, and the toner neutralizing device 61 is excluded together with the air discharged from the toner separating device 60. The toner is configured to pass through. The toner neutralizing device 61 has an X-ray generator as a weak X-ray source having an energy of 3 keV to 9.5 keV (not shown), and the X-ray emitted from the X-ray generator is converted into the device. It is configured so that it can irradiate toner passing through the inside. Of course, it is assumed that at least shielding measures in which a predetermined shielding plate or the like is appropriately installed are taken so that X-rays do not leak out from the developing device 100, preferably the toner charge eliminating device 61.

  Accordingly, the charge removal by the toner charge removal device 61 is performed by irradiating the toner particles which are removed by the action of the toner separation device 60 and carried in the air flow in the air with X-rays. That is, the ionized air having positive and negative polarities collides with the toner particles, whereby the charge removal of the toner particles is completed.

  For this reason, even if it is circulated in this way, it can be sufficiently expected that the charge amount of the toner particles obtained by being charged by the toner charging device 3 is relatively uniform.

  As described above, according to the toner separation device of the seventh embodiment, in the configuration in which the toner excluded by the separation device is returned to the toner charging device and reused, the toner charge removal device is provided in the middle of the return path, The toner charge removal device releases the inappropriate charge state from the toner to be restored, so that the charge amount of the reused toner particles charged by the toner charge device can be made relatively uniform. This makes it possible to increase the possibility of using the toner once excluded for development, and to improve the development utilization efficiency of the toner.

  In each of the above-described embodiments, the photosensitive drum is exemplified as the electrostatic latent image holding member. However, the photosensitive drum is not limited to this, and the electrostatic latent image holding member is moved to a developing position such as a belt shape by a predetermined amount. Any suitable structure may be used as long as it is a holding body having an electrostatic latent image holding surface on which an electrostatic latent image is formed before reaching.

1 shows a first embodiment of the present invention, a developing device having the toner separation device of the first embodiment, and holding an electrostatic latent image carrying an electrostatic latent image visualized by the developing device It is the schematic which shows the outline | summary with a body. FIG. 4 shows a toner separation device according to a second embodiment of the present invention, in which (a) is a longitudinal sectional view of the toner separation device, and (b) is an end surface sectional view taken along the line bb in FIG. . FIG. 6 is a cross-sectional view of a toner separation device according to a third embodiment of the present invention. 4 shows a toner separation device according to a fourth embodiment of the present invention, in which (a) is a view of the toner separation device taken along the line aa in FIG. (B), and (b) is in FIG. It is a bb arrow directional cross-sectional view. FIG. 7 is a schematic diagram of a toner separation device according to a fifth embodiment of the present invention. FIG. 10 is a longitudinal sectional view of a toner separation device according to a sixth embodiment of the present invention. FIG. 10 is a block diagram illustrating a toner separation device according to a seventh embodiment of the present invention and illustrating each device provided in association with the toner separation device. The measurement principle of a general "E-SPART method" is shown and it is the schematic of the measuring device using this measurement method. FIG. 2 is a graph illustrating an applied voltage waveform (high electric field asymmetric waveform) for generating an electric field, explaining the principle underlying the present invention. It is a graph explaining the principle used as the premise of this invention and showing the displacement amount of ions other than a specific ion. It is a graph explaining the principle used as the premise of this invention and showing the displacement amount of a specific ion. It is the schematic which demonstrated the principle used as the premise of this invention and showed the operation | movement concept of the ion filter. FIG. 2 is a graph illustrating the principle underlying the present invention and showing the proportional relationship between the electric field strength of a DC electric field EC and the charge amount (Q / m) per unit mass of toner particles in a certain toner. FIG. 5 is a schematic diagram showing a configuration for charging a general “one-component toner” and showing frictional charging by a metal blade.

Explanation of symbols

1, 20, 30, 40, 50, 60 Toner separation device 2 Toner supply device 3 Toner charging device 5 Toner introduction port 6 Toner discharge port 7 Device body 8 First electrode (flat plate shape)
8A First electrode (cylindrical) 8a First electrode (multiple electrodes)
9 Second electrode (flat plate shape) 9A Second electrode (cylindrical shape)
9a Second electrode (multiple electrodes)
9b Second electrode (second electrode for double-sided installation)
DESCRIPTION OF SYMBOLS 10 Air inlet 11 Air outlet 12 Power supply for asymmetric voltage waveform generation 13 DC voltage generation power supply 13a DC voltage generation power supply (for plural electrodes individually)
14 Opening (or groove) 31 Partition 51 Electret 61 Toner static eliminating device 100 Developing device 200 Electrostatic latent image holding member T Toner particles

Claims (11)

A toner separation device having a toner introduction port into which charged toner is introduced and a toner discharge port that is installed toward the electrostatic latent image holding member and discharges the charged toner to the electrostatic latent image holding member. ,
A path from the toner introduction port to the toner discharge port is provided with a first electrode and a second electrode arranged in parallel and facing each other with a space therebetween;
An asymmetric voltage waveform and a DC voltage waveform are applied to the second electrode, and charged toner other than a toner having a predetermined charge amount reaches at least the toner discharge port between the first electrode and the second electrode. And generating an electric field that is excluded from between the electrodes,
A toner separation device characterized in that an air flow for discharging the charged toner to be removed out of the device is formed between the electrodes.   2. The toner separating apparatus according to claim 1, wherein the first electrode is a common electrode, and second electrodes are provided on both sides of the first electrode so as to face each other.   The toner separation device according to claim 1, wherein the first electrode and the second electrode are formed in a cylindrical shape having different diameters and are arranged concentrically. A plurality of second electrodes are provided, and independent DC voltage generating power sources are provided for these second electrodes,
2. A voltage obtained by superimposing a DC voltage waveform supplied from a DC voltage generating power source for the second electrode and an asymmetric voltage waveform is applied to each of the second electrodes. The toner separation device according to any one of 1 to 3.   4. An opening or a groove that is larger than the particle diameter of the toner is provided in one or both of the first electrode and the second electrode. Toner separation device. Providing an air inlet for introducing air and an air outlet for discharging the introduced air to form the air flow;
6. The toner removed outside from the inter-electrode region by the action of an electric field generated between the first electrode and the second electrode is discharged together with air from an air discharge port. The toner separating apparatus as described.   7. The toner separating apparatus according to claim 1, wherein a plurality of air inlets and air outlets are provided.   8. The toner separating apparatus according to claim 1, wherein the surface inside the apparatus is covered with an electret except for an electrode portion.   9. The toner separation device according to claim 1, wherein the toner particles discharged together with air from the air discharge port are returned to the toner charging device and used again.   The toner separation device according to claim 1, wherein the toner particles to be reused are neutralized by a neutralization device before entering the toner charging device.   The toner separation device according to claim 1, wherein the configuration according to claim 1 is a basic unit, and a plurality of basic units are provided.

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