JPH11249382A - Corona electrifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corona electrifying device capable of stably imparting large electrification amount with little dispersion to the particulates of substance to be electrified. SOLUTION: This corona electrifying device is equipped with an electrode 30a on a strong electric field side generating an ion and a counter electrode 30b attracting the generated ion; and electrifies the substance to be electrified by attaching the ion generated in the electrode 30a to the substance to be electrified at the time of corona discharge. Then, the electrodes 30a and 30b have a major axis in the carrying direction of the substance to be electrified, and the electrode 30b is constituted by surrounding the electrode 30a at a position equivalent to the electrode 30a. Then, the cross-sectional shape of the electrode 30b is circular or pentagonal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona charging device for charging fine particles, and more particularly, to a method for charging a colorant particle in an image recording apparatus to electrostatically control the same, and a method in an air cleaning apparatus. In this case, the fine particles are charged and electrostatically controlled.

[0002]

2. Description of the Related Art Fine particles having a small inertia force can be uniquely controlled by electrostatic force by charging, and the control by electrostatic force is relatively small, simple, clean, small in energy, high in control accuracy, Since it has many advantages such as high-speed control, it is used in various fields. For example,
In the charging of powder fine particles of about 1 μm, corona charging is used as a method for charging relatively easily without stable and uniform friction. This method has been proposed and put to practical use in the fields of image recording devices, electrostatic coating, electric dust collectors, air purifiers and the like.

The specific structure of the corona charging device will be described below with reference to FIGS. The arrow indicates the moving direction of the charged object.

[0004] The charging device shown in FIG.
0a and the plate-like electrode 30b,
between the electrodes 30a and 30b (in the direction of arrow A) when the ions I generated in the vicinity of a move to the counter electrode 30b.
Is charged by adhering to the fine particles Cps of the charged object conveyed to the substrate.

[0005] The charging device ((a) of FIG.
(B) shows a side view) shows a wire electrode 30a of several tens μm.
When the ions I generated near the strong electric field side electrode 30a move to the counter electrode 30b, the charged object is transported between the electrodes 30a and 30b (in the direction of arrow A). It is charged by adhering to the fine particles Cps of the substance.

FIG. 13 shows an example in which the charging device shown in FIG. 12 is applied to an image recording apparatus.

The image recording apparatus includes a heating device 10 for heating and vaporizing a color material, a charging device 30 for charging the vaporized color material, and an electric signal corresponding to image data on which the charged color material is to be recorded. Discharge device 5 that discharges intermittently according to
0 comprises a print head 1 integrally formed. The heating device 10 includes an electric heater 10b for heating, and the charging device 30 includes a discharge electrode portion 30a having a wire shape or the like and a counter electrode portion 30b having a plate shape. Further, the ejection device 50 arranges a back electrode portion 50c on the back surface of the recording medium RM in order to induce ejection of the charged coloring material onto the recording medium RM via the ejection holes 90. An intermediate electrode portion 50a (50a) having a so-called shutter function for physically or electrically controlling the discharge of the colorant.
1, 50a2, 50a3), and outputs a corresponding signal in response to an input of an electric signal corresponding to image data to thereby output the intermediate electrode portion 50a (50a1, 50a2, 50a3).
And an intermediate electrode drive control unit 50e that controls the shutter as a shutter function. The intermediate electrode section 50
a (50a1, 50a2, 50a3) is an insulating plate 5
0d.

In the print head 1, a powder ink Ip
Is stored. In the lower part of the print head 1, the ink I
A heating device 10 for heating p is provided, and at the time of printing, the heating device 10 heats the ink Ip to 200 ° C. and vaporizes it (to become a vaporized ink Ipg). The upper half portion of the print head 1 is provided with charging electrodes 30 for charging the ink particles Ips which have been heated and vaporized and then cooled and solidified and aggregated to form the ink particles Ips.
A 0 μm wire electrode (electrode 30a on the strong electric field side) is provided, and the atomized ink particles Ips apply a voltage of +5 kV to the electrode 30a on the strong electric field side (a voltage of 0 V is applied to the counter electrode 30b. To be charged). In the upper part of the print head 1, a hole having a diameter of 300 μm is formed as a discharge hole 90 for discharging the ink particles Ips, and an inner diameter φ300 μm is formed so as to surround the periphery of the discharge hole 90.
Of the intermediate electrodes 50a (50a1, 50a2, 50a3). The charged ink particles Ips are applied to the back electrode 50c and the intermediate electrodes 50a (50a1, 50a2, 50a).
0a3) by applying a predetermined voltage to the discharge holes 90a.
Discharge control is performed on the recording medium RM.

[0009]

However, each of the above charging devices has the following problems.

[0010] In the structure shown in FIG.
Since the space where the ions I exist from the substrate to the plate-shaped counter electrode 30b is small, it is difficult to transport all the fine particles Cps of the object to be charged to this space. In addition, there is a problem that it is difficult to perform charging in which the variation in the charge amount is small because the ion density between the electrodes is significantly different.

In the configuration shown in FIG. 12, the wire electrode 30a
The space in which the ions I exist from the substrate to the plate-shaped counter electrode 30b can be enlarged in the direction perpendicular to the direction of transport of the fine particles Cps of the charged object, and it is somewhat easier to transport the fine particles Cps to this space. As a result, the proportion of the fine particles Cps that are not charged at all can be reduced. However, the transport direction itself has the same problem as the case of FIG.

In addition to the above problems, when charging the fine particles, the fine particles adhere to the electrode 30a on the high electric field side due to the gradient force, and the charging ability including uniformity and stability is deteriorated. There are also problems.

[0013] Such variations in the charge amount and unstable operation immediately appear as deterioration in controllability, and, for example, when used in an image recording apparatus, cause a problem that the quality of an obtained image is impaired.

The present invention has been made in order to solve the above-mentioned problems.
An object of the present invention is to provide a corona charging device capable of stably applying a large amount of charge with little variation to fine particles.

[0015]

According to a first aspect of the present invention, there is provided a corona charging device comprising: an electrode on a strong electric field side for generating ions; and a counter electrode for attracting the generated ions. In a corona charging device for charging by attaching ions generated at the electrode on the high electric field side to the object to be charged, the electrode on the high electric field side and the counter electrode have a long axis in the transport direction of the object to be charged, and The counter electrode is configured to surround the strong electric field side electrode at an equal position with respect to the strong electric field side electrode.

According to a second aspect of the present invention, there is provided the corona charging device according to the first aspect, wherein the cross-sectional shape of the counter electrode is circular or polygonal.

According to a third aspect of the present invention, in the corona charging apparatus according to the first aspect, the electrode on the strong electric field which generates ions during corona discharge is formed by spirally winding a wire in a long axis direction. It is characterized by being wound.

According to a fourth aspect of the present invention, in the corona charging device according to the first aspect, the electrode on the strong electric field which generates ions at the time of corona discharge is formed by spirally winding a wire in a long axis direction. It is wound, and the core of the electrode is made of a heating element.

According to a fifth aspect of the present invention, there is provided a corona charging apparatus according to any one of the first to fourth aspects, wherein the electrode on the strong electric field which generates ions during corona discharge is an electrode end. And a resistance heating element connected thereto.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a corona charging device according to the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a configuration diagram of a corona charging device according to a first embodiment of the present invention.

FIG. 1A shows a side structure, FIG. 1B shows a cross-sectional structure, FIG. 1C shows the state of ion generation on the side surface, and an arrow A indicates the direction of transport of the particles Cps of the charged object. The major axis of the charging device 30 is in the direction of air flow, and has a circular structure that is axially symmetric in a cross-sectional direction with respect to the direction of flow. The electrode 30a on the strong electric field side for generating ions is a tungsten wire 300a of several tens of μm, and the counter electrode 30b for attracting generated ions is 20 mm in inner diameter and 1 mm in thickness.
Is used. As the material of the cylindrical conductor of the counter electrode 30b, for example, aluminum is selected from the viewpoint of workability, and the tungsten wire 3 of the electrode 30a on the high electric field side is selected.
00a is suspended at the center of the counter electrode 30b. For example, -5 kv for the wire electrode 300a and 0 for the counter electrode 30b.
FIG. 1 shows a case where a negative discharge applying a voltage of v is performed.
As shown in (c), when the ions I move from the vicinity of the wire electrode 300a to the counter electrode 30b, the ions I adhere to (collide with) the fine particles Cps carried between the wire electrode 300a and the counter electrode 30b. Then, the fine particles Cps are charged.

In this configuration, as shown in FIG. 1B, the electric field distribution is symmetric about the axis of the wire electrode, and the ions I generated in the vicinity of the electrode 30a on the strong electric field side are uniformly distributed around, that is, 360 degrees in all directions. Therefore, variation due to the transport position of the fine particles Cps is considerably reduced. Further, since the direction of the flow of the particles Cps of the object to be charged is the major axis of the charging device 30, the charging time can be lengthened, and the charge amount can be increased. It is also possible to control the charge amount by adjusting the shaft length. However, when viewed from the long axis of the charging device, there is a problem that variation in discharge occurs depending on the position.

Here, -5k is applied to the wire electrode 300a.
v, the voltage of 0 V is applied to the counter electrode 30 b, but the voltage is not limited thereto, and 0 V and the electrode 30 b are applied to the electrode 300 a.
A voltage of +5 kv may be applied, or a negative discharge other than the above voltage value may be applied.

Conversely, when plus discharge is performed by applying 0 V to the wire electrode 300a and -5 kV to the electrode 30b, + ions I generated around the electrode 300a
Then, the ions I adhere to (collide with) the fine particles Cps carried between the electrode 30a on the high electric field side and the counter electrode 30b, and charge the fine particles Cps. Also in this configuration, the same effect as in the case of the negative discharge can be obtained.

In the above description, 0V is applied to the wire electrode 300a.
Although a voltage of −5 kv was applied to the counter electrode 30 b, the voltage is not limited thereto, and +5 kv and an electrode 3
A voltage of 0 V may be applied to 0b, or a positive discharge other than the voltage value may be applied.

In this embodiment, the electrode 30a on the strong electric field side is used.
, A tungsten wire of several tens of μm was used, but the present invention is not limited to this. Further, it is formed in a shape extended on a straight line, but this shape is not limited to this.

(Second Embodiment) FIG. 2 is a configuration diagram of a corona charging device according to a second embodiment of the present invention.

In this embodiment, the cross-sectional shape of the counter electrode is assumed to be polygonal. Although the cross-sectional shape of the counter electrode has a polygonal feature, a square shape will be described here for convenience of explanation. 2A shows the side structure, FIG. 2B shows the cross-sectional structure, FIG. 2C shows the state of ion generation on the side surface, and the arrow A indicates the transport direction of the fine particles Cps of the charged object.

The counter electrode 30b of the charging device 30 has an inner diameter of 2
A hollow rectangular column-shaped conductor having a thickness of 1 mm and circumscribing 0 mm is used. For example, aluminum is selected as the material of the quadrangular columnar conductor of the counter electrode 30b from the viewpoint of workability, and the tungsten wire 300a of the electrode 30a on the strong electric field side is connected to the counter electrode 30b.
It is suspended in the center.

In this configuration, the space where ions are present is almost the same as in the first embodiment. However, since the structure is a quadrangular prism, it is actually viewed from a cross section as shown in FIG. In this case, the ion density varies more than in the first embodiment. For this reason, the charge amount varies depending on the position where the fine particles are transported. However, since the transport direction of the object to be charged is provided in the long axis direction of the electrode on the strong electric field side and the counter electrode, the above problem is practically within the range of error.

Also, in this embodiment, the same effect can be obtained in the case of a negative discharge as in the previous embodiment and in the case of a positive discharge.

(Third Embodiment) FIG. 3 is a structural view of a corona charging device according to a third embodiment of the present invention.

In this embodiment, the description of the same parts as in the first and second embodiments will be omitted, and only different parts will be described. In the first and second embodiments,
Although the electrode on the high electric field side is formed in a shape in which a tungsten wire of several tens of μm is linearly extended, in the present embodiment, an example in which the structure is spirally wound will be described.
The cross-sectional shape of the counter electrode is not particularly limited, but here, for convenience of explanation, the same circle as that of FIG. 1 of the first embodiment is used. 3A shows a side structure, FIG. 3B shows a cross-sectional structure, FIG. 3C shows a state of ion generation on the side surface, and an arrow A indicates a transport direction of the particles Cps of the charged object.

A metal wire 300a having a diameter of several tens μm is used as the electrode 30a on the strong electric field side of the charging device 30, and the metal wire 300a is, for example, φ4 mm made of ABS resin.
Is wound at a pitch of 2 mm around a wire support 30c made of a solid rod. Wire 300a and wire support 3
0c on the strong electric field side
It is suspended at the center of b.

In this configuration, the ion I is applied to the wire 300a
The discharge points are arranged regularly in the direction of the counter electrode 30b, which is visible from the outside, so that the variation in the amount of generated ions depending on the wire position is reduced. Therefore, the problem of the variation in discharge which has occurred in the first and second embodiments can be considerably improved. As a result, when a cross section perpendicular to the transport direction of the fine particles Cps is viewed from the entrance to the exit of the charging device,
Since the ions I move equally in the space, the fine particles Cp
Regardless of the transport position of s to the charging device, it is equally charged when it is carried out of the charging device. Further, since the structure of the electrode 30a on the strong electric field side can be manufactured with a simple member, there is an advantage that cost can be reduced.

Also in this embodiment, similar to the above embodiments, the same effects can be obtained in the case of a minus discharge or a plus discharge.

(Fourth Embodiment) FIG. 4 is a structural view of a corona charging device according to a fourth embodiment of the present invention.

In this embodiment, the description of the same parts as those in the first to third embodiments will be omitted, and only different parts will be described. This embodiment is based on the third embodiment for convenience of explanation, but is not limited to this.

FIG. 4 shows the side structure, and the arrow A indicates the direction of transport of the particles Cps of the charged object.

The different parts are the electrode 30 on the strong electric field side.
The wire support 30c constituting a has a ceramic heater 30d whose surface is insulated, and is provided with a control device 30e for turning on / off the heater 30d as necessary.

Normally, in the case where corona discharge occurs, that is, where an unequal electric field is generated, the fine particles are attracted to the high electric field side. If particles adhere to the electrode on the high electric field side due to turbulence of the flow at the time of transport, thermal motion of the particles, or the like, the ion generating ability is deteriorated and the uniformity is also deteriorated. for that reason,
In the configuration of this embodiment, the wire electrode 300a can be refreshed to the initial state by vaporizing the attached fine particles again, and as a result, stable and uniform charging can be performed.

The control of the heater 30d may be turned on / off by providing detection means for detecting contamination of the electrode from the discharge voltage characteristic, or may be turned on / off periodically depending on the operation time. Good, always O during operation
N may be set.

In this embodiment, although there is a problem that power consumption increases, since the electrodes are hardly stained, the initial ion generating ability can be maintained, and a stable operation can be guaranteed for a long period of time. In addition, as the temperature near the electrode on the high electric field side rises, the thermal kinetic energy of electrons and ions for ion generation increases, and the ion generation efficiency increases from the discharge side. Hold.

In this embodiment, similar to the above embodiments, the same effects can be obtained in the case of a negative discharge or a positive discharge.

(Fifth Embodiment) FIG. 5 is a structural view of a corona charging device according to a fifth embodiment of the present invention.

In this embodiment, the description of the same parts as those in the first to fourth embodiments will be omitted, and only different parts will be described. This embodiment is based on the third embodiment for convenience of explanation, but is not limited to this.

FIG. 5 shows the side structure, and the arrow A indicates the transport direction of the particles Cps of the charged object.

The different parts are the electrode 30 on the strong electric field side.
This means that the resistance heating element 30g is connected to the end of the metal wire 300a that constitutes a.

For example, when a minus discharge is applied by applying a voltage of -5 kv to the wire electrode 300a and a voltage of 0v to the counter electrode 30b, the ions I are transferred from the vicinity of the wire electrode 300a in the same manner as shown in FIG. When moving to the counter electrode 30b, the ions I adhere to (collide with) the fine particles Cps conveyed between the electrode 30a on the high electric field side and the counter electrode 30b, and charge the fine particles Cps. At the same time, a current also flows through the resistance heating element 30g, and this portion generates heat by Joule heat, and the wire electrode 300a is also sequentially heated by heat conduction. Thereby, the adhesion of the fine particles Cps to the wire electrode 300a can be prevented, and a stable operation can be guaranteed for a long time. Copper or the like having good thermal conductivity is used as the wire material, but tungsten and the like are preferable in consideration of strength and the like.

Since a high voltage is normally applied to the wire electrode 300a, when selecting the resistance heating element 30g, it is necessary to pay some attention to the setting of the resistance value and the like. In other words, the value of the resistor or the like is determined from the power consumption and the applied voltage determined from the set temperature and the amount of heat radiation at that temperature. 30g of high resistance heating element
Is difficult to adjust, an adjusting resistor 30f can be added.

Although the example of the case of the negative discharge has been described above, the same effect can be obtained in the case of the positive discharge.

Also, the configuration of the wire electrode 300a of the electrode 30a on the strong electric field side has been described as a spiral shape.
The shape is not limited to this, and may be, for example, a linear shape. In this case, the same effect as above can be obtained.

In this embodiment, the case where precise uniformity of charging is required has been described. If not, the first or second embodiment is performed without using the wire support 30c. The example suspension method may be used.

(Sixth Embodiment) In this embodiment, an example in which the corona charging device of the present invention is applied to a print head of an image recording apparatus will be described. As the corona charging device, the charging device of any one of the first to fifth embodiments may be used according to the required charging accuracy.

FIG. 6 is a diagram showing the configuration. Although the corona charging device of the fourth embodiment is used here for convenience of description, the present invention is not limited to this.

The printing head 1 of the image recording apparatus includes a heating device 10 including an electric heater 10b, a granulating device 20, a charging device 30 including two types of electrodes 30a and 30b, and a rectifying device 4.
0, the intermediate electrode 50a (50
a1, 50a2) and a back electrode 50c
0, a transport device 60.

A powder colorant Cp is stored inside the ink pot 10a. A heating device 10 including an electric heater 10b for heating the powder colorant Cp is provided below the ink pot 10a. Following the heating device 10, a granulating device 20 for aggregating and granulating the heated and vaporized colorant Cpg is provided. A sheet heating element 20a that imparts conductivity and generates heat by Joule heat is provided. Following the granulating device 20, a charging device 30 for charging the colorant particles Cps is provided. A rectifying section 40 is provided at a position following the charging device 30, and for example, a plurality of rectifying plates 40a are arranged. A discharge device 50 is provided at a position following the rectification unit 40. The discharge device 50 is provided with a hole of φ300 μm as a discharge hole 90 for discharging the colorant particles Cps, and further surrounds the periphery of the discharge hole 90. As described above, the intermediate electrodes 50a (50a1, 50a2) having an inner diameter of φ300 μm are provided on both surfaces of the insulating plate 50d. Further, a back electrode 50 is provided with a gap from the insulating plate 50d so that the recording medium RM can be transported.
c is provided. After the discharge device 50,
For example, a transfer device 60 such as a DC micro fan is provided. With such a structure, the colorant particles can be circulated by sequentially transporting the colorant particles to the series of devices in the direction of arrow B.

Next, the operation inside the print head 1 of the image recording apparatus configured as described above will be described.

During standby, the DC micro fan 60a
To move the air in the chamber in the direction of arrow B. During printing, the powder colorant Cp is heated to 200 ° C. by the heating device 10 and vaporized. As a coloring agent, when a colored ink is used, yellow uses an anthrisothiazole-based, quinophthalone-based, pyrazolonazo-based, pyridoneazo-based, styryl-based, and the like, and magenta uses an anthraquinone-based, dicyanoimidazole-based, thiadiazole-azo-based, For example, azo, anthraquinone, naphthoquinone, and indoaniline can be used for cyan.

When the colorant Cp is vaporized and conveyed to the granulating apparatus 20, it is cooled, solidified and agglomerated to form colorant particles Cps. When cooling naturally without using the planar heating element 20a,
Colorant particles Cps with an average particle size of 0.8 μm were produced. On the other hand, when the granulating apparatus 20 is heated by the planar heating element 20a and the colorant is gradually cooled, the particle size of the colorant particles Cps can be controlled. Next, the colorant particles Cps are charged to the charging device 30.
Transported to In the charging device 30, the electrode 30 on the strong electric field side is used.
By giving a potential difference between the two electrodes, the wire electrode 300a and the counter electrode 30b, to the extent that ionization of air occurs around the electrode a, ions are generated near the electrode 300a, and the ions are applied to the electrode 30b according to the lines of electric force. Moving.
At this time, the colorant particles Cps collide with and adhere to the colorant particles Cps.
s is charged. Specifically, for example, when 0 V is applied to the wire electrode 300a and +5 kV is applied to the counter electrode 30b, the negative ions move from the electrode 300a to the electrode 30b, so that the colorant particles Cps are negatively charged. On the other hand, the control device 30e
Heater 30 by the control signal from
d is turned on / off. When the surface of the heater 30d becomes higher than the melting point of the colorant, the colorant particles attached to the metal wire 300a are vaporized again and conveyed. Charged colorant particles C
The flow of air including ps is rectified by the rectifying plate 40 a provided in the rectifying unit 40 and is conveyed to the discharge device 50. In the ejection device 50, ejection is controlled to the recording medium RM through the ejection holes 90 by applying a predetermined voltage to the intermediate electrode 50a (50a1, 50a2) and the back electrode 50c. Specifically, for example, a voltage of 0 V or -500 V is applied to the intermediate electrode 50a (50a1, 50a2) according to the output signal of the control unit 50e having the intermediate electrode drive control corresponding to the electric signal of the image data to be recorded. , Back electrode 5
A voltage of +1.0 to +2 kV is applied to 0c. Here, the electric field formed in the ejection hole 90 causes the intermediate electrode 50
Only when both the voltages a1 and 50a2 are 0 V, the charged colorant particles Cps are ejected and recorded on the recording medium RM.

In an actual image recording apparatus, as shown in FIG. 7, the print head 1 is used as a serial head, and is scanned in the line direction while performing the above-described operation, whereby an image is formed on the recording medium RM.

Although the case of the negative discharge has been described in the charging device 30, the positive discharge may be used, and the voltage applied to each electrode is not limited to the above value.

As in the present embodiment, devices 10, 20, 3 for generating (heating, granulating), charging, and discharging the colorant particles Cps.
0, 50 and the device 60 for sequentially transporting the colorant particles Cps to the respective devices, the colorant particles Cp generated
Since s passes through each device without fail, the use efficiency of the colorant is improved and the charge amount is made uniform.

With respect to the improvement of the use efficiency of the colorant, since the inside of the chamber is apparently high in airtightness, the air in the chamber flows in the chamber with little variation in the flow velocity, that is, the above-described series of devices 10, 20, 30,. By circulating 40 and 50, the colorant particles Cps not used for recording can be reused. Colorant particles Cp not used for recording
Since s has a high rate of small charge amount, these colorant particles Cps are conveyed to the charging device 30 again to increase the charge amount. After that, it is used for recording, so that the use efficiency is improved. Further, since the charge amount is increased, the ejection speed is improved, and as a result, the recording speed is improved.

The uniform charging of the colorant particles is based on the following reasons.

1) When corona discharge occurs, that is, when an unequal electric field is generated, the fine particles are attracted to the high electric field side. When particles are attached to the electrode due to turbulence of the flow at the time of transport, thermal motion of the particles, etc., the ion generating ability is deteriorated and the uniformity is also deteriorated.
A heater 30d is wound around and supported by the electrode 30a on the high electric field side, and if necessary, the heater 30d is turned on to vaporize the adhered colorant particles Cps again, whereby the electrode 30
a can be refreshed to its initial state. As a result, stable and uniform charging can be performed.

2) The coloring material becomes solid particles at the time of charging by the granulating device 20, and the air ions generated by the charging device 30 move according to the lines of electric force and collide with the coloring material particles Cps to be charged. Since it is possible, almost the entire amount of the vaporized colorant Cp can be charged, and the charging efficiency can be greatly improved.

3) The colorant particles Cps are transferred by the transport device 60.
Is transported in the flow of air, so that the amount of the ions that are dragged by the ionic wind and adhere to the counter electrode 30b can be considerably reduced.

When the charging efficiency was measured here, as shown in FIG. 8, in the measurement result b in the configuration of the conventional example (FIG. 13), there were many uncharged colorant particles Cps. In the measurement result a, the colorant particles Cps which were not charged at all but varied in the charge amount were hardly found.

(Seventh Embodiment) In this embodiment, an example in which the corona charging device of the present invention is applied to an air cleaner will be described. As the corona charging device, the charging device of any one of the first to fifth embodiments may be used according to the required charging accuracy.

FIG. 9 is a diagram showing the configuration, and the arrow C indicates the direction of suction of air containing dust. Although the corona charging device of the first embodiment is used here for convenience of description, the present invention is not limited to this.

The air purifier includes a suction device 60 for conveying air containing dust D into the purifier, a filter 70 for removing relatively large dust D in advance, and a minute filter which is not removed by the filter 70. The charging device 30 includes a plurality of charging devices 30 for charging the dust D1 and a collecting device 80 for collecting the dust D2 charged by the charging device 30. The suction device 60 is not particularly limited as long as it is a suction fan 60b that can suck air. The filter 70 may be knitted with a polyethylene film, for example. The collecting device 80 includes parallel plate electrodes 80a, 8
0b are paired at intervals of 5 mm, and are constituted by a plurality of pairs.

Next, the operation of the air purifier configured as described above will be described.

By the operation of the intake fan 60b, air containing dust D in the direction of the arrow is conveyed into the air purifier. The conveyed air passes through the filter 70, and relatively large dusts are generated due to physical adhesion.
And removed from the air. Where filter 7
If the stitch size of 0 is too small, clogging due to dust occurs, and the stitch cannot be used stably for a long period of time. Therefore, it is necessary to make the size appropriate. Thereafter, the air from which relatively large dust has been removed by the fill 70 is conveyed to the charging device 30.

In the charging device 30, for example, the wire electrode 30
A positive discharge is performed by applying a voltage of +3 kv to 0a and a voltage of 0v to the counter electrode 30b. Although not shown, when + ions I move from the vicinity of the wire electrode 300a to the counter electrode 30b, the ions I And adheres (collides) with the dust particles D1 transported between the counter electrode 30b and charges the dust particles D1. Thereafter, the charged dust D2 is transported to the collection device 80.

In the collection device 80, a pair of electrodes 80a,
Voltages of +2 kv and 0 v are applied to the pair of electrodes 80a and 80b, respectively.
Due to the electric field formed between the electrodes b, the positively charged dust particles D2 move toward the electrode 80b, and eventually adhere to the electrode 80b and are collected.

Although the above description has been made using positive discharge, negative discharge may be used. However, in the case of a negative discharge, the same amount of ions as in the positive discharge is generated, so that there is an advantage that the voltage is reduced. However, the amount of ozone generated during discharge is about one order larger than that in positive discharge,
Considering the odor and the effect on the human body, positive discharge is more preferable.

Further, the electrode pair 80a, 80
b is applied to the electrodes 300 a and 30 of the charging device 30.
b, that is, +3 of the electrode 300a in the above case.
By setting kv and +2 kv of the electrode 80a to have the same polarity, it is not necessary to prepare high voltage power supplies individually, and one high voltage power supply is sufficient. Further, the voltage applied to the electrode 80a and the electrode 80b may be changed for each operation, for example. As described above, by alternately changing the voltage applied to the electrode pairs 80a and 80b, the electrode pair 8
Since the direction of the electric field formed between 0a and 80b changes, the charged dust D2 adheres to each of the electrodes almost uniformly, so that a stable operation can be performed for a longer period.

As described above, in the present air purifier, dust having a small variation and a large charge amount can be charged, so that the dust collecting efficiency, that is, the cleaning performance can be improved.

In the above configuration, an electrode pair is used as the collecting device 80, but the present invention is not limited to this. For example,
Since the charge amount of the dust increases and the dispersion decreases, a conductor made of aluminum foil or SUS foil formed in a honeycomb shape (honeycomb or corrugated cardboard) as shown in FIG. 10A is grounded. It is also possible to use an electret film formed by bonding a resin film such as an electretized fluororesin or PET, which is also formed in a honeycomb shape and formed into an electret. When a grounded conductor is used, when the charged dust passes through the inside of the honeycomb, the dust adheres to the conductor by an image force and is collected. In the case where an electret film is used, as shown in FIG. 10 (b), the surface having the opposite polarity to the charged polarity of the dust is configured to be on the inner side of the honeycomb. For example, when the dust D2 is positively charged, two films are bonded together so that the outer surface becomes negative. Thus, when the charged dust D2 passes through the inside of the honeycomb, it adheres to the conductor by electrostatic force and is collected.

The above configuration of the trapping device 80 has the advantage that no external power supply is required, and the advantage that the area for collecting dust can be increased, thereby enabling stable operation for a long period of time. have.

The embodiments described so far are not limited to the above description unless the gist of the present invention is changed.

[0084]

According to the corona charging device of the present invention, the following effects can be obtained in each claim.

According to the first and second aspects of the present invention, the generated ions move evenly in all directions of 360 degrees, so that the variation in charging is considerably reduced. Thus, a charging operation capable of stably giving a large charge amount can be realized.

According to the third aspect of the present invention, since the discharge points are regularly arranged and the variation in the amount of ion generation due to the wire position is reduced, a very uniform and large charge amount is obtained when the sheet is carried out of the charging device. The applied charged fine particles are generated. Further, since the structure itself can be manufactured with simple members, there is an effect that cost can be reduced.

According to the fourth and fifth aspects of the present invention, the refresh function can realize a stable and uniform charging operation without deteriorating the ion generating ability. It also has the effect of increasing the efficiency of generating ions from the discharge side as a secondary effect.

As described above, according to the present invention, it is possible to provide a charging device capable of stably providing a large amount of charge for a long term with a small variation in fine particles.

[Brief description of the drawings]

FIG. 1 is a configuration diagram for explaining a first embodiment of a charging device according to the present invention.

FIG. 2 is a configuration diagram for explaining a second embodiment of the charging device according to the present invention.

FIG. 3 is a configuration diagram for explaining a third embodiment of the charging device according to the present invention.

FIG. 4 is a configuration diagram for explaining a fourth embodiment of the charging device according to the present invention.

FIG. 5 is a configuration diagram for explaining a fifth embodiment of the charging device according to the present invention.

FIG. 6 is a configuration diagram for explaining an embodiment of a print head of an image recording apparatus to which the charging device according to the present invention is applied.

FIG. 7 is a diagram for explaining the overall configuration of an image recording apparatus to which the charging device according to the present invention is applied.

FIG. 8 is a diagram showing a charge amount distribution of colorant particles in an image recording device to which the charging device according to the present invention is applied and in a conventional image recording device.

FIG. 9 is a configuration diagram for explaining an embodiment of an air purifier to which the charging device according to the present invention is applied.

FIG. 10 is a configuration diagram illustrating an example of a collecting device in an air purifier to which the charging device according to the present invention is applied.

FIG. 11 is a configuration diagram illustrating an example of a conventional charging device.

FIG. 12 is a configuration diagram for explaining an example of another conventional charging device.

13 is a configuration diagram for explaining an example of a print head of an image recording apparatus to which the conventional charging device of FIG. 12 is applied.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 heating device 20 granulating device 30 charging device 30 a electrode on strong electric field side 300 a wire electrode 30 b counter electrode 30 c wire support 30 d heater 30 e heater control device 30 f adjusting resistor 30 g resistance heating element 40 rectifying device 50 discharge device 60 transport device 70 Filter 80 Collection device

Claims (5)

[Claims] 1. An electrode on a strong electric field side for generating ions,
A counter electrode for attracting the generated ions,
In a corona charging device for charging by adhering ions generated at the electrode on the strong electric field side to the object to be charged at the time of corona discharge, the electrode on the strong electric field side and the counter electrode have a long axis in the transport direction of the object to be charged. The corona charger according to claim 1, wherein the counter electrode is configured to surround the strong electric field side electrode at an equal position with respect to the strong electric field side electrode. 2. The corona charger according to claim 1, wherein the cross-sectional shape of the counter electrode is circular or polygonal. 3. The corona charging device according to claim 1, wherein the electrode on the high electric field side for generating ions during corona discharge is formed by spirally winding a wire in a longitudinal direction. 4. The electrode on the high electric field side for generating ions during corona discharge is formed by spirally winding a wire in a longitudinal direction, and a core of the electrode is made of a heating element. 2. The corona charging device according to 1. 5. The corona charging device according to claim 1, wherein the electrode on the strong electric field that generates ions during corona discharge is formed by connecting a resistance heating element to an end of the electrode. .