JPH05165302A - Corona discharging device of image formation device - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the amount of ozone, nitrogen oxides, etc. generated and to obtain sufficient charging performance. [Structure] A plurality of discharge points 8 are discretely formed on a discharge electrode member 7 to reduce a dielectric breakdown region in the air, and the discharge electrode member 7 and a photoconductor 14 (charged body).
The intermediate member 10 is disposed so that the openings on both sides of the through hole 10a face each other, and the electron flow amplification from the discharge light is performed on the inner peripheral surface of the through hole 10a of the intermediate member 10 by the photoelectron multiplication effect. Attaching the photoelectron amplification material 4 having the physical properties to be performed,
The discharge light generated from the electrode hits the photoelectron amplifying material 4 and the electrons fly out to double the electron flow so that sufficient charging performance can be obtained. By doing so, it is possible to reduce the dielectric breakdown region and the current value, which are effective for suppressing ozone generation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge device for an image forming apparatus such as a copying machine or a printer which applies a high voltage to a discharge electrode member to charge an object to be charged.

[0002]

2. Description of the Related Art Conventionally, as a corona discharge device (charging device) for charging a photosensitive member, which is a member to be charged, using a corona discharge provided in, for example, a copying machine, a casing (shield) is used as shown in FIG. It is generally known that a discharge wire 82 stretched in a metal 81 is applied with a high voltage by a discharge power source 84 to charge a photoreceptor 83.

Such a non-contact type discharge device is shown in FIG.
As shown in FIG. 7, a control grid member 85 is provided between the discharge wire 82 and the photoconductor 83 to stabilize the charging potential of the photoconductor 83.
Is also provided so that the variation is absorbed by grounding an extra discharge current. In addition, as the charging device, there is also a charging device that charges a charging target by non-contact charging in a minute gap formed between the charging roller and the charging target.

[0004]

However, in such a conventional corona discharge device, ozone and NOx (nitrogen oxides) generated during discharge are problems, and in order to stabilize the charging potential of the photoconductor. In the case where the control grid material is provided in the above, about 90% of the discharge current is discarded by being grounded, so that there is a drawback that the efficiency is low. Also,
The one using a charging roller can reduce the generation of ozone, but this method requires a cleaning mechanism, and if there is an insulation defect in the photosensitive layer of the charged body, the charge is concentrated. Then, there is a drawback that an abnormal image is output.

The present invention has been made in view of the above problems, and it is possible to obtain sufficient charging performance while being able to reduce the amount of generation of substances causing problems such as ozone and nitrogen oxides. The purpose is to do. It is also an object to make the entire device compact and to manufacture it at low cost.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a corona discharge device for an image forming apparatus as described above in which a plurality of discharge points are formed discretely on a discharge electrode member and the discharge is performed. A plurality of through holes are formed between the electrode member and the body to be charged so that the openings face each other, and the opening on the discharge electrode member side of the through holes is formed near the discharge point. An intermediate member made of an insulating material is provided, and a photoelectron amplifying material having the property of amplifying electron flow from discharge light by a photoelectron multiplication effect is applied to or attached to the inner peripheral surface of the through hole of the intermediate member. The amplifying material is connected to a power supply for electronic replenishment.

The position where the photoelectron amplifying material is applied or attached to the inner peripheral surface of the through hole of the intermediate member is opened from the position at a predetermined distance from the discharge point of the discharge electrode member to the charged body side to the charged body side. It is effective to arrange the discharge point of the discharge electrode member in each through hole of the intermediate member.

Further, between the discharge electrode member and the member to be charged,
A plurality of intermediate members made of an insulating material, each of which has a plurality of through holes communicating from the surface on the side of the discharge electrode member to the surface on the side of the body to be charged, are provided, and at least one of the intermediate members of the plurality of layers is provided as a photoelectron. The photoelectron amplification material is formed by a photoelectron amplification material having the property of amplifying the electron current from the discharge light by the multiplication effect, or the photoelectron amplification material is applied or attached to the inner peripheral surface of each through hole formed in the layer, and the photoelectron amplification is performed. The material should be connected to a power supply for electronic replenishment.

Then, in the corona discharge device of the image forming apparatus, a void is formed between the layers of the intermediate members of a plurality of layers,
It is advisable to dispose a control grid material in the voids or to let hot air flow in the voids between the layers. Further, the through hole of each layer of the intermediate member of the plurality of layers, the hole diameter of the layer on the charged member side is smaller than that of the layer on the discharge electrode member side, and the hole area ratio is the product of the hole diameter and the number of holes. Are preferably formed so that the layer on the charged body side is larger than the layer on the discharge electrode side.

Further, in the corona discharge device of the image forming apparatus, the surface of the intermediate member facing the member to be charged is disposed close to the surface to be charged of the member to be charged with a constant gap, or the intermediate member is disposed. The through hole of the layer on the side of the discharge electrode member of the member is formed so that the opening area on the side of the discharge electrode member is large and the opening area gradually decreases toward the charged body side, and the through hole of the layer on the charged body side is formed. It is advisable to form the holes such that the opening area on the discharge electrode member side is small and the opening area gradually increases toward the charged body side.

Further, between the discharge electrode member and the member to be charged, openings are formed on both sides of the discharge electrode member, and the slots extend along the arrangement direction of the discharge points so that a plurality of discharge points can be inserted. An intermediate member made of an insulator having a circular through hole is provided, and electron flow amplification is performed from discharge light by a photoelectron multiplication effect on the inner peripheral surface of the through hole of the intermediate member or at a position adjacent to the through hole. A photoelectron amplification material having physical properties may be applied or attached, and the photoelectron amplification material may be connected to a power supply for electron replenishment.

In any one of the above-mentioned image forming apparatus corona discharge devices, the state in which the surface of the discharge electrode member to be attached to the intermediate member is bent with respect to the surface forming the discharge point when the discharge electrode member is mounted. , The discharge electrode member, the intermediate member and the photoelectron amplifying material are detachably integrated, and the radiation is emitted near the discharge point of the discharge electrode member on the inner peripheral surface of the through hole of the intermediate member. It is more effective if a substance that emits light or a substance that emits ultraviolet rays is provided.

[0013]

According to the corona discharge device of the image forming apparatus configured as described above, the electrode of the discharge electrode member is made into a pin electrode by separating a plurality of discharge points, so that the dielectric breakdown area in the air can be reduced. The discharge light generated from each electrode hits the photoelectron amplification material in the plurality of through holes formed in the intermediate member, and the electrons excited by the light jump out to multiply the electron flow. Is amplified and added to the electron flow or ion flow due to the original corona discharge, so sufficient charging performance can be obtained even if the current value is reduced. Therefore, since it is possible to effectively reduce the dielectric breakdown region and reduce the current value in order to suppress the ozone generation, it is possible to suppress the ozone generation to the minimum.

Further, the coating or attaching position of the photoelectron amplifying material on the inner peripheral surface of the through hole of the intermediate member is from a position at a predetermined distance from the discharge point of the discharge electrode member to the charged body side to the opening on the charged body side. If the interval is between, it is possible to prevent the discharge light from striking the photoelectron amplifying material and retaining the doubled space charges near the discharge point, so that stable discharge can be continued.

By disposing each discharge point of the discharge electrode member in each through hole of the intermediate member, the discharge light emitted from the electrode is efficiently emitted toward the photoelectron amplifying material without being diffused behind it. Therefore, the space charge can be doubled by an efficient photomultiplier effect.

Further, a plurality of layers of intermediate members made of an insulating material having a plurality of through holes similar to those described above are arranged between the discharge electrode member and the member to be charged, and among the plurality of layers of intermediate members. At least one layer is formed of a photoelectron amplifying material having physical properties of amplifying an electron flow from discharge light by a photoelectron multiplication effect,
Alternatively, if the photoelectron amplification material is applied or attached to the inner peripheral surface of each through hole formed in that layer and the photoelectron amplification material is connected to a power supply for electron replenishment, an intermediate member that performs photoelectron amplification is separated from other intermediate materials. Since it can be manufactured separately from the members,
Manufacturing is easier and the parts accuracy is improved.

If a void is formed between the layers of the intermediate member and the control grid material is disposed in the void, the charged member can be stably charged by the stable discharge, and the interlayer can be charged. If hot air is allowed to flow in the voids, it is possible to suppress changes in the characteristics of the photoelectron amplifying material, where surface characteristics tend to change significantly when absolute humidity is high, and deterioration with time is inevitable at high humidity. It is possible to prevent deterioration of the discharge electrode member and the intermediate member.

In addition, the through hole of each layer of the intermediate member having a plurality of layers has a smaller opening diameter in the layer on the charged member side than the layer on the discharge electrode member side, and is the product of the opening diameter and the number of openings. If the porosity is formed so that the layer on the charged body side is larger than the layer on the discharge electrode side, the electron flow from the electrode toward the charged body side spreads toward the end, and uneven charging is reduced.
Furthermore, if the surface of the intermediate member facing the charged body is arranged close to the charged surface of the charged body with a constant gap, efficient charging can be performed and uneven charging can be eliminated.

Then, the through hole of the layer of the intermediate member on the side of the discharge electrode is formed so that the area of the hole on the side of the discharge electrode is large and the area of the hole is gradually reduced toward the charged body. If the through hole of the layer on the charging body side is formed so that the opening area on the discharge electrode member side is small and gradually increases toward the charged body side, the assembling property when mounting the discharge electrode member It is possible to improve the air flow rate and improve the air intake property into the through hole.

Further, between the discharge electrode member having the plurality of discharge points and the member to be charged, openings are provided on both sides of the discharge electrode member so that the plurality of discharge points can be inserted. An intermediate member made of an insulator having slot-shaped through holes extending along the arrangement direction is provided, and a photoelectron amplifying material is applied to the inner peripheral surface of the through hole of the intermediate member or a position adjacent to the through hole. If the intermediate member is attached and connected to a power source for replenishing electrons, the intermediate member can be inexpensive because the shape of the through hole portion is simplified.

Furthermore, if the mounting surface of the discharge electrode member to the intermediate member is mounted in a bent state with respect to the surface forming the discharge point when the discharge electrode member is mounted, the entire device can be mounted. If the discharge electrode member, the intermediate member, and the photoelectron amplifying material are detachably integrated, they can be manufactured at low cost and the maintainability is improved. By disposing a substance that emits radiation or a substance that emits ultraviolet rays in the vicinity of the discharge point of the discharge electrode member on the inner peripheral surface of the through hole of the intermediate member, the air near the discharge point is ionized and a discharge occurs. As it becomes easier, stable charging is possible.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. 1 is a perspective view showing a corona discharge device of a laser printer which is an image forming apparatus according to an embodiment of the present invention, FIG. 2 is an overall configuration diagram showing a laser printer equipped with the corona discharge device, and FIG. It is a longitudinal cross-sectional view of the corona discharge device of 1.

The laser printer shown in FIG. 2 has a sheet feeding roller 15 of a sheet feeding device 11 provided in the printer body 1.
The recording paper P in the paper feed cassette 2 is fed in the direction of arrow A by. Then, the fed recording paper P is conveyed to the registration roller pair 13 and temporarily stopped, and is transferred to the latent image carrier composed of the photoconductor 14 which is a drum-shaped charged body at a predetermined timing corresponding to the image. Be transported. The photoconductor 14
Is rotated counterclockwise by a drive source (not shown), the surface of which is charged by a corona discharge device (charging device) 5, and the laser beam La emitted from the laser emission device 12 is irradiated onto the surface. As a result, an electrostatic latent image is formed.

The latent image is visualized by toner as it passes through the developing device 17, and the visible image is transferred by the transfer device 18 onto the recording paper P conveyed to the transfer portion of the photoconductor 14. Then, the visible image transferred to the recording paper P is fixed by the fixing device 19 and is discharged onto the paper discharge tray 21 by the paper discharge roller 3.

On the other hand, the photoreceptor 14 after the transfer of the visible image
The residual toner on the surface of the toner is removed by the cleaning device 23 having the cleaning blade 22, and then the charge is removed by the charge removing device 24. Then, the toner removed from the photoconductor 14 by the cleaning blade 22 is collected and stored in a toner collecting chamber (not shown) by a collecting auger.

The corona discharge device 5 applies a high voltage to the discharge electrode member 7 by the discharge power source 6 shown in FIG. 3 to charge the photoconductor 14 which is the member to be charged, and as shown in FIG. A plurality of discharge points 8 are formed on the discharge electrode member 7 in a discrete manner, and a plurality of through holes are formed between the discharge electrode member 7 and the photoconductor 14 so that the openings face both sides thereof. An intermediate member 10 made of an insulating material having an opening 10b of each through hole 10a on the side of the discharge electrode member 7 (FIG. 3) formed near the discharge point 8 is provided.

Then, each through hole 10 of the intermediate member 10
As shown in FIG. 3, a tubular photoelectron amplifying material 4 formed of a material having a physical property of amplifying the electron flow from the discharge light by a photoelectron multiplication effect is fitted into the inner peripheral surface of a, and the photoelectron amplifying material is attached. 4 is grounded via a Zener diode 16 that generates a constant voltage as a power supply for replenishing electrons, and electrons are replenished to the photoelectron amplifying material 4. A high-voltage constant-voltage power supply or a constant-current power supply may be used as the power supply for electronic replenishment, or a constant-current circuit may be provided or grounded via a resistor.

The discharge electrode member 7 is formed, for example, by etching or precision pressing a thin copper plate as shown in FIG. 1 with a plurality of electrodes 7a aligned in a saw-tooth shape at intervals of a pitch Pi, and each tip thereof is formed. The discharge points 8 are provided, and holes 7b, 7 for positioning and fixing are provided at both ends in the longitudinal direction.
c are formed respectively, screws 9 are inserted therein, and they are fixed to the intermediate member 10 by screwing them into the screw holes formed in the intermediate member 10.

Further, a current-carrying terminal 7d is extended on the side of the discharge electrode member 7 opposite to the electrode 7a, and the conducting wire portion of the lead wire 27 is connected thereto, and the other end side of the lead wire 27 is shown in FIG. Is connected to the discharging power supply 6. The electrode shape of the discharge electrode member 7 is not limited to the saw-tooth shape as shown in FIG. 1 except for an electrode member such as a wire that does not have discrete discharge points. It may be arranged.

Further, since the intermediate member 10 is concerned about the leakage of the discharge electrode, ceramics, which is an insulator and is a weak dielectric material, for example, is used, but a material having an insulator and a weak dielectric material is used. It may be formed by molding. Then, the plurality of through holes 10a formed in the intermediate member 10
If the one opening 10b faces the discharge electrode member 7 side and the other opening 10c faces the photoconductor 14 side, the hole diameter is not particularly limited.

The photoelectron amplifying material 4 is an n-type semiconductor that is excited by the light and emits electrons when the light hits the light.
A porous ceramics such as iC (silica) or ZnO (zinc oxide) is formed in a tubular shape with a collar, and is inserted or outserted into each through hole 10a of the intermediate member 10 as shown in FIG. Install by.

The photoelectron amplifying material 4 may be formed by coating the inner surface of a tubular member made of a material having a certain volume resistance with the above-mentioned porous ceramic in a liquid state before firing. , CVD method (scientific vapor deposition) in which various raw material gases are heated and guided to the inner surface of the tubular member to react with them to deposit the product on the adhered surface to form a film.
It may be formed by coating or the like.

In this corona discharge device (charging device) 5, when a high voltage (-) is applied to the discharge electrode member 7, glow discharge is started at the discharge point 8 at the tip of the electrode, from which discharge light is emitted from each intermediate member 10. It is discharged toward the inside of the through hole 10a. When the discharge light hits the tubular photoelectron amplifying material 4 attached in each through hole 10a, the electrons excited by the light jump out, and they are overlapped to form an electron flow and are multiplied.

The electron flow is in a state of being added to the electron flow and the ion flow emitted from the original electrode, and flows in the through holes 10a toward the photoconductor 14 side. Since this electron flow is generated while being dispersed, there is little variation in the discharge distribution. In addition, since the electrode does not have a concentrated dielectric breakdown region like when a discharge wire is used and the discharge current is small, it is possible to suppress the generation of ozone and nitrogen oxides (NOx) and stabilize the photosensitive member 14. In this state, it can be sufficiently charged.

The photoelectron multiplying action performed by the photoelectron amplifying material 4 is performed by repeatedly reflecting several times as many electrons on the inner wall surface of the photoelectron amplifying material 4 in each through hole 10a. The effect is most remarkable in a vacuum, but it is effective in an air because the electrons hit oxygen, nitrogen, etc. but ionize them to a small extent, though not so much as in a vacuum.

FIG. 4 is a vertical sectional view similar to FIG. 3, showing only the main part of an embodiment of a corona discharge device in which the position where the photoelectron amplifying material is attached is restricted, and the portion corresponding to FIG. The same reference numerals are attached. In this embodiment, the attachment position of the photoelectron amplifying material (slightly different from that of FIG. 3) 4 on the inner peripheral surface of the through hole 10a of the intermediate member 10 is changed from the discharge point 8 of the discharge electrode member 7 to the photosensitive member. Predetermined distance L1 to 14 side
From the position where is placed to the end of the opening 10c on the photoconductor 14 side.

By doing so, when the photoelectron amplifying material 4 is placed in the opening 10b on the entrance side of the through hole 10a, the ions due to the photoelectron multiplication effect are produced near the electrode, and the space charge is discharged. Since it is generated in the vicinity and interferes with the continuous discharge, the efficiency is deteriorated, but this is not the case.
Therefore, the photoelectron amplifying material 4 is not arranged near the discharge point 8 in the through hole 10a on the ion flow path leading to the photoconductor 14 as described above, and a certain distance L1
Should be placed in the position where

Further, in this corona discharge device, since each discharge point 8 of the discharge electrode member 7 is arranged in each through hole 10a of the intermediate member 10, the ion current generated from each discharge point 8 at the tip of the electrode is Although it diverges to some extent behind the electrode, it can be efficiently photomultiplied in the through hole 10a.

FIG. 5 is a longitudinal sectional view showing an embodiment of a corona discharge device in which a plurality of layers of intermediate members are arranged between the discharge electrode member 7 and the photosensitive member 14, and the portion corresponding to FIG. Are given the same reference numerals. This corona discharge device
A plurality of discharge points 8 are formed on the discharge electrode member 7 as in the embodiment of FIG.
And a plurality of through holes 31a, 34 which are respectively formed between the discharge electrode member 7 and the photoconductor 14 and communicate with the surface on the discharge electrode member 7 side and the face on the photoconductor 14 side.
intermediate members 31 and 3 made of an insulator in which a and 32a are formed
2 and one of the intermediate members, a photoelectron amplifying material 34, are arranged in a plurality of layers, and the photoelectron amplifying material 34 positioned in the middle of the plurality of layers is omitted in FIG. As in the example, it is connected to a power supply for electronic replenishment.

When the intermediate member is divided into a plurality of layers as described above, manufacturing advantages such as the straightness of the layers can be easily obtained and the size of each component can be reduced. .. When it is desired to obtain straightness with higher accuracy, an insulator such as alumina ceramics or a metal layer having an insulating layer film may be used.

Further, the photoelectron amplifying material 34 is entirely formed of a porous ceramic such as SiC (silica) or ZnO (zinc oxide) as in this embodiment, and as in the embodiment described with reference to FIG. It is also possible to apply or coat a photoelectron amplifying material on the inner peripheral surface of each through hole formed in a large number in an intermediate member formed of a material having a certain volume resistance.

FIG. 6 is a vertical cross-sectional view showing an embodiment of a corona discharge device provided with a control grid material, and parts corresponding to those in FIG. 5 are designated by the same reference numerals. This corona discharge device is similar to the embodiment of FIG.
A plurality of layers of intermediate members 31 and 32 and a photoelectron amplifying material 34, which is one of the intermediate members, respectively, and
Voids 33, 35 are formed between the respective layers, and a control grid material 36 for stabilizing the charging potential of the photoconductor 14 is arranged in the void 35.

The control grid material 36 is manufactured by etching a metal material such as stainless steel (SUS) and incorporating it between the photoelectron amplifying material 34 and the intermediate member 32. The grid power supply is not shown in FIG. By doing so, the discharge electrode member 7
The discharge (charging) from the discharge point 8 can be further stabilized.

FIG. 7 shows an embodiment in which warm air is allowed to flow between the layers of the intermediate member, and the portions corresponding to those in FIG. 5 are designated by the same reference numerals. In this embodiment, the intermediate member 3
1 and a photoelectron amplifying material 34 which is one of the intermediate members, and a space 33 is formed between the photoelectron amplifying material 34 and the photoconductor 14 and is heated by a heater (not shown) or the like. The warm air Who is made to flow.

By doing so, the surface characteristics of the photoelectron amplifying material 34 are likely to change greatly when the absolute humidity in the air is high, and the discharge electrode member 7 and the intermediate member 31 are suitable for the passage of time at high humidity. Deterioration is inevitable, but since these members are ventilated by the warm air Who, it is possible to cope with environmental changes such as humidity, so that it is possible to stabilize against environmental changes. Further, even a small amount of ozone or nitrogen oxide (NOx) generated can be transferred to the filter or the like by the warm air Who.

FIG. 8 is a perspective view showing an embodiment in which the through hole of each layer of the intermediate member having a plurality of layers is made to have a higher aperture ratio as it goes toward the layer on the photoconductor side, and corresponds to FIG. The parts have the same signs. In this example,
The through holes 31a and 32a of the intermediate members 31 and 32 and the through hole 34a of the photoelectron amplification material 34 which is one of the intermediate members are
Photoreceptor 1 than the layer (intermediate member 31) on the discharge electrode member 7 side
The opening diameter of the layer (intermediate member 32) on the 4 side is made smaller, and the opening ratio, which is the product of the opening diameter and the number of openings, is closer to the layer on the photoreceptor 14 side than the layer on the discharge electrode member 7 side. Are formed so as to be large.

That is, the aperture diameter D2 of the through hole 34a formed in the photoelectron amplifying material 34 is smaller than the aperture diameter D1 of the through hole 31a of the intermediate member 31, and the intermediate diameter on the side of the photoconductor 14 is smaller than the aperture diameter D2. The through hole 32a of the member 32 is formed so that the opening diameter D3 becomes smaller.
The number of openings a, 34a, 32a is larger in the through holes 34a than in the through holes 31a, and larger in the through holes 32a than in the through holes 34a. The porosity, which is the product, has the following relationship. Opening diameter D1 x Opening number <Opening diameter D2 x Opening number <Opening diameter D3
× Number of holes

In this way, the ion current generated at the discharge point 8 of the discharge electrode member 7 is directed to the side of the photoconductor 14 in the plural layers formed by the intermediate member 31, the photoelectron amplifying material 34, and the intermediate member 32. Since it gradually spreads toward the end and flows through a wide range while being acclimated through the fine through holes, uneven discharge (charging) is reduced.

FIG. 9 shows an embodiment in which a constant gap is provided between the photosensitive member-side intermediate member and the photosensitive member, and the portions corresponding to those in FIG. 7 are designated by the same reference numerals. In this embodiment, the surface 34b of the photoelectron amplifying material 34, which is one of the intermediate members, facing the photoconductor 14 is the charged surface 1 of the photoconductor 14.
4a is formed in an arc shape, and the surface 34b is formed on the surface to be charged 14
It is placed close to a with a constant gap δ. As described above, when the surface 34b of the photoelectron amplifying material 34 is arranged close to the photoconductor 14 and the gap δ is opened, the charging efficiency can be increased, so that the uneven charging of the photoconductor 14 is reduced.

FIG. 10 shows an embodiment of a corona discharge device in which the through hole of the intermediate member has a special shape.
The same reference numerals are given to the portions corresponding to. In this embodiment, each through hole 41a of the intermediate member 41 located on the discharge electrode member 7 side has a large opening area on the discharge electrode member 7 side,
The through holes 44a of the photoelectron amplifying material 44, which is formed so that the opening area becomes gradually smaller toward the side of the photoconductor 14 (mortar shape) and forms a layer on the side of the photoconductor 14, are formed on the discharge electrode member 7 side. Has a small opening area, and the opening area gradually increases toward the photoconductor 14 (octopus pot shape).

By forming the through holes 41a and 44a in this manner, the through hole 41a of the intermediate member 41 on the discharge electrode member 7 side is formed.
Since it has a mortar shape, workability is improved when the discharge electrode member 7 is assembled to the intermediate member 41 by the attachment structure shown in FIG. 1, and air is taken into the through hole 41a. Become. In addition, by surrounding the inner wall near the discharge electrode member 7, a newly created ion flow can be directed to the photoconductor 14 side, and by stacking this, the efficiency of photoelectron multiplication action can be improved. Therefore, the ion flow obtained as a whole is increased.

11 and 12 show an embodiment in which the through hole formed in each intermediate member has a slot-like shape, and the portions corresponding to those in FIG. 1 are designated by the same reference numerals. .. In this embodiment, the discharge electrode member 7 and the photoconductor 14
(FIG. 12) between the two openings 51 on both sides.
b and 51c face each other, and an intermediate member 51 made of an insulator is provided in which one slot-shaped through hole 51a extending along the arrangement direction of the discharge points 8 is formed so that a plurality of discharge points 8 are inserted. A part of the intermediate member 51 is formed of, for example, the porous ceramics described in the embodiment of FIG. 3 having the physical property of amplifying the electron flow from the discharge light by the photoelectron multiplication effect to form the photoelectron amplifying material 54. As shown in FIG. 11, one opening 54b is formed in the through hole 51a, and the other opening 54c is formed in a slot shape corresponding to the opening 51c.

In this embodiment, the discharge electrode member 7
Holes 7e, 7e for fixing (only one side is shown in FIG. 11) are formed at both ends of each of them, and projecting upward in the overhanging portions 52, 53 of the intermediate member 51, respectively. The discharge electrode member 7 is fixed to the intermediate member 51 by fitting the respective engaging pin portions 52a and 53a, and the mounting holes 54d and 54d (the optoelectronic amplifying material 54 are formed on the lower surfaces of both ends thereof, respectively). (Only one side is shown) is attached to the intermediate member 51 by being fitted into the engaging pin portions 52b and 53b which are respectively provided so as to project upward in correspondence with the intermediate member 51, thereby attaching the discharge electrode member 7 and the intermediate member. 51 and the photoelectron amplification material 54 are integrated, and in this state, they can be attached to and detached from the printer body 1 (FIG. 2).

The discharge electrode member 7, the intermediate member 51, and the photoelectron amplifying member 54 may be individually attached or detached. Further, the photoelectron amplifying material 54 is connected to the Zener diode 16 which generates a constant voltage as a power source for replenishing electrons through the wiring 56 and is grounded, whereby electrons are replenished.

As described above, each hole shape of the through holes 51a, 54a and the opening 51c, which serve as a flow path of the electron flow of the intermediate member 51 including the photoelectron amplifying material 54, is one slot shape (two or more holes may be formed). By making it), the photoelectron amplifying material 54 and the intermediate member 51 can be easily manufactured, and the cost can be reduced. Further, by integrating these parts, the size can be reduced, and the attachment / detachment during maintenance can be facilitated.

13 and 14 show an embodiment in which, when the discharge electrode member is attached to the intermediate member, the attachment surface thereof is attached in a bent state with respect to the surface forming the discharge point. 1 and FIG. 3 are given the same reference numerals. In this embodiment, the mounting surface 67a of the discharge electrode member 67 to the intermediate member 61 is formed as shown in FIG.
As shown in FIG. 3, when the discharge electrode member 67 is attached, the discharge electrode member 67 is attached in a bent state with respect to the surface 67b forming the discharge point 8. That is, the intermediate member 61 is formed of an insulating material into a substantially rectangular parallelepiped as shown in FIG. 14, a slit groove 61a extending in the longitudinal direction is formed on the upper surface thereof, and the lower surface side is opened as shown in FIG. To form an opening 61b (corresponding to the through hole 51a in the embodiment of FIG. 11) so that the slit groove 61a communicates with the opening 61b.

The groove width of the slit groove 61a is substantially equal to the plate thickness of the discharge electrode member 67.
The discharge electrode member 67 inserted therein is held near the discharge point 8 as shown in FIG. Further, a step portion 61c is formed on the inner surface of the open portion 61b of the intermediate member 61, and the step portion 61c has a photoelectron amplifying function similar to the photoelectron amplifying material 4 described in FIG. Thus, the photoelectron amplifying material 64 having a plurality of through holes 64a therein can be held without play. When the photoelectron amplification material 64 is attached to the step portion 61c, the photoelectron amplification material 6
13 is inserted into the intermediate member 61 from the lower side of the open portion 61b in FIG. 13 to a position where the lower protrusion formed on the stepped portion 61c shown in FIG.

On the other hand, on both ends in the longitudinal direction of the upper surface of the intermediate member 61, the claw portions 61d and 61d which can be displaced in the arrow C direction of FIG. 13 by the elastic force of the material itself (only one side is shown in FIG. 14). ) Are formed respectively, and in the mounted state shown in the figure, each claw portion 61 is formed in each square hole 67c (only one side is shown) formed at both ends of the discharge electrode member 67 shown in FIG.
d is fitted in each of the intermediate members 61 of the discharge electrode member 67.
Is installed. According to this embodiment, the corona discharge device can be made more compact.
In FIG. 13, the discharge electrode member 67 is replaced by the intermediate member 6
If the upper end side is set to tilt to the right of the position shown in the figure in the state of being attached to 1, the overall height is further reduced.

FIG. 15 is a vertical cross-sectional view showing an embodiment in which a substance that emits radiation is arranged on the inner peripheral surface of the through hole of the intermediate member, and the portions corresponding to those in FIG. It is attached. In this embodiment, the through hole 5 of the intermediate member 51
A radioactive substance 71 that emits radiation is arranged near the discharge point 8 of the discharge electrode member 7 on the inner peripheral surface of 1a. By doing so, by placing the radioactive substance 71 near the discharge point 8, it is possible to ionize the surrounding air and facilitate discharge. Therefore, the discharge start voltage is correspondingly low and the power supply can be made small. Even if a substance that emits ultraviolet rays is provided instead of the radioactive substance 71, ionization of air near the discharge point 8 can be promoted.

[0060]

As described above, according to the present invention, the photoelectrons generated by the emitted electrons and the discharge light emitted from the discrete discharge points repeatedly striking the photoelectron amplifying material in the through holes of the intermediate member. Since the electron flow is multiplied by the emitted electrons emitted by the multiplication action and is directed to the charged body, the charged body can be charged by efficient corona discharge with a small discharge current. Therefore, since the discharge current can be reduced, the generation of ozone and the like can be suppressed.

If the photoelectron amplifying material is attached at a position between the discharge point of the discharge electrode member and the opening on the charged body side from a position at a predetermined distance from the charged body, the photoelectron multiplying effect is generated. Since the space charge due to the electrons does not stay near the discharge electrode, the discharge is continued in a stable state.

Further, if each discharge point of the discharge electrode member is arranged in each through hole of the intermediate member, the ion current from each discharge point does not diverge to the back of the discharge electrode. Therefore, the photomultiplier effect can be enhanced. Further, between the discharge electrode member and the member to be charged, a plurality of layers of intermediate members made of an insulating material having a plurality of through-holes communicating from the surface on the side of the discharge electrode member to the surface on the side of the member to be charged are arranged. If at least one layer of the above is formed of a photoelectron amplifying material, or if a photoelectron amplifying material is applied or attached to the inner peripheral surface of the through hole, the intermediate member can be separated according to its function and the manufacturing thereof can be facilitated. .. Also, straightness can be easily obtained.

By forming voids between the plurality of intermediate members and disposing the control grid material in the voids, discharge (charging) can be further stabilized. In addition, if a void is formed between the intermediate members formed in a plurality of layers and hot air is allowed to flow in the void, the photoelectron amplification material has a large change in surface characteristics when the absolute humidity in the air is high. Although the discharge electrode member and the intermediate member are inevitably deteriorated with time in high humidity, the change in environment due to the change in environment such as humidity can be avoided by ventilating these members with warm air. Can be stabilized against. Further, a slight amount of ozone or nitrogen oxide (NOx) generated can be transferred to the filter or the like by the hot air.

Further, the through hole of each layer of the plurality of intermediate members has a smaller opening diameter in the layer on the charged body side than the layer on the discharge electrode member side, and the open area ratio is smaller than that on the discharge electrode side. If the layer on the charged body side is made larger, the ion flow generated at the discharge point of the discharge electrode member will gradually form fine through holes in the layer formed by the plurality of intermediate members toward the charged body. Since it flows through a wide range while being accustomed to the end spread, uneven discharge (charging) is reduced. Also,
If the surface of the intermediate member facing the charged body is disposed close to the charged surface of the charged body with a constant gap, the charging efficiency can be increased, so that uneven charging on the charged body is reduced.

Further, the through hole of the layer of the intermediate member on the side of the discharge electrode member is formed so that the opening area on the side of the discharge electrode member is large and the opening area is gradually reduced toward the charged body side. If the through hole of the layer on the charged body side is formed so that the opening area on the discharge electrode member side is small and gradually increases toward the charged body side, the through hole of the layer on the discharge electrode member side will be formed. Since the inlet side is wide, the workability when assembling the discharge electrode member is improved, and the air can be easily taken into the through hole to improve the charging property, and the stacking state can improve the efficiency of the photomultiplier effect. As a result, the ion flow obtained as a whole is increased.

An intermediate member made of an insulating material having slot-shaped through holes extending along the arrangement direction of the discharge points so as to insert a plurality of discharge points between the discharge electrode member and the member to be charged is formed. If it is installed and a photoelectron amplification material is provided there,
Since the through holes have a slot shape extending along the arrangement direction of the discharge points, the intermediate member can be easily manufactured, and the cost can be reduced.

If the mounting surface of the discharge electrode member to the intermediate member is mounted in a bent state with respect to the surface forming the discharge point when the discharge electrode member is mounted, the discharge electrode material Since it is attached to the intermediate member in a bent state, the entire corona discharge device can be made compact. Further, if the discharge electrode member, the intermediate member, and the photoelectron amplifying material are detachably integrated, the size can be further reduced, the cost can be reduced, and the detachment at the time of maintenance is facilitated, so that the maintainability is improved.

Further, by disposing a substance that emits radiation or a substance that emits ultraviolet rays in the vicinity of the discharge point of the discharge electrode member on the inner peripheral surface of the through hole of the intermediate member, the surrounding air is ionized to cause discharge. Since it can be easily caused, stable discharge can be performed, the discharge start voltage can be lowered, and the power supply can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a corona discharge device of a laser printer which is an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is an overall configuration diagram showing a laser printer equipped with the corona discharge device.

3 is a vertical cross-sectional view of the corona discharge device of FIG.

FIG. 4 is a vertical cross-sectional view similar to FIG. 3, showing only a main part of an embodiment of a corona discharge device in which a position where a photoelectron amplification material is attached is restricted.

FIG. 5 is a vertical sectional view showing an embodiment of a corona discharge device in which a plurality of layers of intermediate members are arranged between a discharge electrode member and a photosensitive member.

FIG. 6 is a vertical cross-sectional view showing an embodiment of a corona discharge device provided with a control grid material.

FIG. 7 is a vertical cross-sectional view showing an embodiment in which warm air is allowed to flow between layers of an intermediate member.

FIG. 8 is a perspective view showing an embodiment in which the through hole of each layer of the intermediate member having a plurality of layers is increased in aperture ratio toward the layer on the photoconductor side.

FIG. 9 is a vertical cross-sectional view showing an embodiment in which an intermediate member on the photoconductor side is arranged with a constant gap provided between the photoconductor and the intermediate member.

FIG. 10 is a vertical cross-sectional view showing an embodiment of a corona discharge device in which a through hole of an intermediate member has a special shape.

FIG. 11 is a perspective view showing an embodiment in which a through hole of each intermediate member is formed in a slot shape by one hole.

FIG. 12 is a vertical sectional view of the same.

FIG. 13 is a vertical cross-sectional view showing an embodiment in which, when the discharge electrode member is attached to the intermediate member, the attachment surface is attached to the surface forming the discharge point in a bent state.

FIG. 14 is a perspective view of the same embodiment.

FIG. 15 is a vertical cross-sectional view showing an embodiment in which a substance that emits radiation is arranged on the inner peripheral surface of the through hole of the intermediate member.

FIG. 16 is a schematic view showing an example of a corona discharge device using a conventional discharge wire.

FIG. 17 is a schematic view showing an example of a conventional corona discharge device using a conventional discharge wire and a control grid material.

[Explanation of sign]

4,34,44,54,64 Photoelectron amplification material 5 Corona discharge device 6 Discharge power source 7,67 Discharge electrode member 8 Discharge point 10, 31, 32, 41, 51, 61 Intermediate member 10a, 31a, 32a, 34a, 41a, 44a, 5
1a, 54a Through-holes 10b, 10c, 51b, 51c Opening 14 Photoreceptor (charged body) 14a Charged surface 16 Zener diode (power supply) 33, 35
Gap 34b, 67b Surface 36 Control grit material 67a Mounting surface 71 Radioactive material

Claims (13)

[Claims] 1. A corona discharge device of an image forming apparatus for charging a member to be charged by applying a high voltage to a discharge electrode member by a discharge power source, wherein a plurality of discharge points are formed discretely on the discharge electrode member. A plurality of through-holes are formed between the discharge electrode member and the member to be charged so that the openings face each other on both sides thereof, and the opening of the through-hole on the side of the discharge electrode member is formed. An intermediate member made of an insulator formed near the discharge point is provided, and a photoelectron amplifying material having physical properties of amplifying electron flow from discharge light by a photoelectron multiplication effect is provided on the inner peripheral surface of the through hole of the intermediate member. A corona discharge device for an image forming apparatus, characterized in that the photoelectron amplifying material is applied or attached and is connected to a power source for replenishing electrons. 2. A corona discharge device for an image forming apparatus according to claim 1, wherein the photoelectron amplification material coating or attachment position on the inner peripheral surface of the through hole of the intermediate member is charged from the discharge point of the discharge electrode member. A corona discharge device for an image forming apparatus, characterized in that it is provided between a position at which a predetermined distance is placed on the body side and the opening on the charged body side. 3. The corona discharge device of the image forming apparatus according to claim 1, wherein each discharge point of the discharge electrode member is arranged in each through hole of the intermediate member. Corona discharge device. 4. A corona discharge device of an image forming apparatus for charging a member to be charged by applying a high voltage to a discharge electrode member by a discharge power source, wherein a plurality of discharge points are formed discretely on the discharge electrode member. , A plurality of layers of intermediate members made of an insulator are formed between the discharge electrode member and the member to be charged, and a plurality of through holes communicating from the surface on the discharge electrode member side to the surface on the member side to be charged are formed. Then, at least one layer of the intermediate members of the plurality of layers is formed of a photoelectron amplifying material having the property of performing electron flow amplification from discharge light by the photoelectron multiplication effect, or of each through hole formed in the layer. A corona discharge device for an image forming apparatus, wherein the photoelectron amplifying material is applied or attached to an inner peripheral surface, and the photoelectron amplifying material is connected to a power supply for replenishing electrons. 5. A corona discharge device for an image forming apparatus according to claim 4, wherein voids are formed between layers of the plurality of intermediate members, and a control grid material is arranged in the voids. Corona discharge device for forming equipment. 6. A corona discharge device for an image forming apparatus according to claim 4, wherein voids are formed between the plurality of layers of intermediate members, and hot air is allowed to flow in the voids. Corona discharge device for forming equipment. 7. The corona discharge device for an image forming apparatus according to claim 4, wherein the through hole of each layer of the intermediate member of the plurality of layers is charged more than the layer on the discharge electrode member side. The layer on the body side has a smaller aperture diameter, and the aperture ratio, which is the product of the aperture diameter and the number of apertures, is formed so that the layer on the charged body side is larger than the layer on the discharge electrode side. A corona discharge device for an image forming apparatus, which is characterized by: 8. The corona discharge device of the image forming apparatus according to claim 1, wherein a surface of the intermediate member facing the charged body is a charged surface of the charged body. A corona discharge device for an image forming apparatus, characterized in that they are arranged close to each other with a constant gap. 9. The corona discharge device of the image forming apparatus according to claim 4, wherein the through hole of the layer of the intermediate member on the side of the discharge electrode member is an opening area on the side of the discharge electrode member. Is formed so that the opening area becomes gradually smaller toward the charged body side, and the through-hole of the layer on the charged body side has a small opening area on the discharge electrode member side and goes to the charged body side. Therefore, the corona discharge device of the image forming apparatus is characterized in that the opening area is gradually increased. 10. A corona discharge device of an image forming apparatus for charging a body to be charged by applying a high voltage to a discharge electrode member by a discharge power source, wherein a plurality of discharge points are formed discretely on the discharge electrode member. Between the discharge electrode member and the body to be charged, openings are formed on both sides of the discharge electrode member, and each has a slot shape extending along the arrangement direction of the discharge points so as to insert the plurality of discharge points. A physical property in which an intermediate member made of an insulating material having a through hole is provided, and electron flow amplification is performed from discharge light by a photoelectron multiplication effect at an inner peripheral surface of the through hole of the intermediate member or a position adjacent to the through hole. A corona discharge device for an image forming apparatus, characterized in that a photoelectron amplifying material having the above is applied or attached, and the photoelectron amplifying material is connected to a power supply for replenishing electrons. 11. A corona discharge device for an image forming apparatus according to claim 1, wherein a mounting surface of the discharge electrode member to the intermediate member is a discharge point when the discharge electrode member is mounted. A corona discharge device for an image forming apparatus, wherein the corona discharge device is attached in a state of being bent with respect to a surface on which an image is formed. 12. The corona discharge device of the image forming apparatus according to claim 1, wherein the discharge electrode member, the intermediate member, and the photoelectron amplifying material are detachably integrated. Corona discharge device for image forming device. 13. The corona discharge device of the image forming apparatus according to claim 1, wherein the radiation is provided in the vicinity of the discharge point of the discharge electrode member on the inner peripheral surface of the through hole of the intermediate member. A corona discharge device for an image forming apparatus, which is provided with a substance that emits or a substance that emits ultraviolet rays.