JP3289267B2 - Corona discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of dirt on a grid, a corona wire and a wire shield of a corona discharge device, and improvement of deterioration of an image carrier due to ozone.

[0002]

2. Description of the Related Art Generally, in an electrostatic recording apparatus, an entire surface of an image carrier made of an insulative photoconductor is charged by a corona discharge device, and the image carrier is irradiated with light so as to correspond to an image of a document. A visible image is formed by forming an electrostatic latent image and developing the electrostatic latent image with a thermoreversible developer. Then, when the image carrier is used again in the next image forming process, after the visible image is transferred to a transfer paper or the like, the charges remaining on the image carrier are removed by the corona discharge device. Further, some residual toner is cleaned by the cleaning device and reused. Such a corona discharge device is also used in an electrophotographic copying machine.
In order to uniformly and effectively impart a corona charge to the surface of the image carrier, or to effectively remove the charge, a corona discharge device is provided in close proximity to the surface of the image carrier. In general, an electrode (grid) is provided between the first and second electrodes in order to absorb an excessive charge. The corona discharge device normally generates a corona charge as described above by applying a high voltage to a corona wire as a discharge electrode. At that time, the air around the corona wire causes dielectric breakdown, the air in this part is ionized, and the ions generated by the ionization move according to their polarities and collide with the gas molecules of the air present in the discharge device, causing The movement of the molecules creates a kind of wind. This wind is generally called ion wind, and flows out from the back of the discharge device toward the vicinity of the image carrier. When the ionic wind flows out, outside air flows in from a portion where discharge is small, that is, near both ends of the discharge device in order to maintain the average of the atmospheric pressure inside the conductive shield.

The place where the electrophotographic copying machine is placed is not always a beautiful place, and there are various sources of dirt such as dust in the air and smoke of cigarettes. In such an environment, when discharge occurs, outside air containing a lot of dust flows in from both ends of the discharge device, and contaminates the corona wire, the grid electrode, and the wire shield, and uniformly covers the surface of the image carrier. In addition, there has been a problem that it is impossible to effectively discharge or remove electricity.

[0004]

To solve this problem, as disclosed in Japanese Utility Model Publication No. 57-93942, a corona discharge device is provided in close proximity to the surface of the image carrier to uniformly charge the surface of the image carrier. In order to prevent partial deterioration of the image carrier due to the influence of ozone carried by the ion wind, measures have been taken to change the flow of the ion wind by providing an insulating shield at the end of the discharge device. However, such measures increase the ozone concentration on the surface of the image carrier as a whole, so that the deterioration of the image carrier proceeds, and the potential rises and becomes unstable, leading to deterioration in image quality. It is hard to say that it is an effective method. Accordingly, an object of the present invention is to prevent overall and partial deterioration of the image carrier, to prevent dust from adhering to a grid, a corona wire, and a wire shield, and to provide uniform charging for a long period of time. Is to obtain a high quality image.

[0005]

FIG. 1 is a perspective view of a conventional corona discharge device. 1 is a corona discharge device, 2
Is a wire shield member (hereinafter simply referred to as a shield member) of the device, 5 is a corona wire, 3 is an attachment end block for attaching the corona wire 5 constituting the discharge electrode to the shield member 2, 4 is a power terminal, Reference numeral 6 denotes a grid, and 7 denotes an image carrier. When a high voltage is applied to the corona wire 5 of the corona discharge device 1 configured as described above and a discharge occurs, an ion wind is generated like white arrows A, E, and F, and the inside of the discharge device 1 starts from the end. Central convection is strong. This is because the discharge is more inactive than the center because the block 3 is located at the end, so the ionization proceeds more strongly at the center than at the ends, so the convection is also stronger at the center than at ends E and F. It is because it becomes. On the other hand, as shown by white arrows B, C, and D, the clean wind from the outside that does not include dust and the like flows into the corona discharge device 1 from the vicinity of the central portion thereof so as to be balanced. In addition, dirty wind from the outside including dust and the like flows into the inside of the corona discharge device 1 from the end as shown by the black arrow.

Since the wind indicated by the black arrow contains a large amount of toner and dust from inside and outside the machine, the end of the grid 6 of the discharge device 1, the corona wire 5, and the shield member 2 are immediately stained. The change in the resistance value due to the contamination causes nonuniform charging potential of the image carrier 7 and deterioration in discharge performance. In addition, ozone is concentrated at the central portion due to the ionic wind convected from the end portion toward the central portion, and the central portion of the image carrier 7 is greatly affected by ozone as compared with the end portion. In view of the above, according to the present invention, the air inflow prevention means is provided between the longitudinal end block of the shield member and the grid. This prevents the inflow of dirty air from the end of the corona discharge device, and uniformly disperses the ozone in the corona discharge device so that it does not concentrate at the central portion, thereby deteriorating the overall deterioration of the image carrier. The purpose of the present invention is to prevent electrical and / or partial deterioration, prevent dust from adhering to grids, corona wires and wire shields, and provide uniform charging for a long time. Therefore, the air inflow prevention means is arranged at least at the end according to the ozone generation distribution. When the air inflow prevention member is provided, it is necessary to attach the air inflow prevention member to the shield member by using a sealing member such as Mylar. However,
There is a problem that the position of bonding the air inflow prevention member and the shield member is not easily determined, and it takes too much time for assembly. Then, if they are bonded together, there is a problem that it is difficult to remove the dirty or broken air inflow prevention member when replacing it.

Accordingly, an object of the present invention is to provide an air inflow prevention member which can be assembled in a short time. It is another object of the present invention to provide an air inflow prevention member that can be easily attached and detached. Still another object of the present invention is to provide an air inflow prevention member that can be accurately attached to a predetermined position with respect to a shield member and that can be fixed so as not to move in the vertical and horizontal directions.
In order to achieve this object, the air inflow prevention member is provided with a concave or convex positioning means, and the end block or the like is provided with a convex or concave positioning means so as to engage with the concave or convex.

[0008]

Embodiments of the present invention will be described below. FIG. 2 is a perspective view of a corona discharge device having an air inflow prevention unit according to the first embodiment of the present invention. In FIG.
The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. 8 is a downstream air inflow prevention member, 10
Denotes a back side air inflow prevention member. The downstream air inflow prevention member 8 and the rear air inflow prevention member 10 together constitute air inflow prevention means for preventing inflow of ion wind at the end of the discharge electrode 3. It is desirable that the downstream air inflow prevention member 8 has a width of about 10 to 30% of the width of the discharge region. The mounting height is desirably reduced to such a degree that it does not contact the image carrier 7 (there is no problem if the image carrier 7 does not come into contact with any scratches, etc.), but it is the same height as the grid 6, or 1 to 2 mm. There is no problem on the above. The back side air inflow prevention member 10 preferably has a width of about 10% to 30% of the width of the discharge region, similarly to the downstream side air inflow prevention member 8, and has the same width as the downstream air inflow prevention member 8. It is desirable that The downstream air inflow prevention member 8 and the rear air inflow prevention member 10 are disposed at both ends of the shield member 2 in order to effectively prevent the flow of wind from the outside.

FIG. 3 shows a first embodiment of the air inflow prevention means of the present invention.
It is an assembly drawing of the Example of. In FIG. 3, reference numeral 11 denotes an upstream air inflow prevention member composed of a light-shielding mylar, which constitutes air inflow prevention means. Upstream air inflow prevention member 1
Reference numeral 1 covers the entire surface of the discharge device 1 and prevents entry of toner and the like from the cleaner into the discharge device 1. In addition, it also has a role of blocking light from the erase lamp.
It is desirable to lower the mounting height of the upstream air inflow prevention member 11 to such a degree that the upstream air inflow prevention member 11 does not come into contact with the image carrier 7 as in the case of the downstream air inflow prevention member 8. There is no. Reference numeral 9 denotes an air inflow prevention member, which constitutes air inflow prevention means. The air inflow prevention member 9 is attached to the arc shield 3 a on the image carrier side of the end block 3, and is provided between the attachment end block 3 and the grid 6. Further, it is possible to prevent a dirty wind from flowing from the outside between the grid 6 and the end block 3, and to use an air-permeable and flexible member such as urethane foam to retain ozone remaining at the end. Can also be reduced by exhausting air. The air inflow prevention member 9 uses a flexible member so as not to deform the grid 6, and the arc shield 3b, the grid 6, the upstream air inflow prevention member 11, and the downstream air inflow prevention member 8 are used.
It is desirable that the size be such that it is sealed on all four sides.

FIG. 4 shows a second embodiment of the air inflow prevention means of the present invention.
The following shows an example. The first embodiment shown in FIG. 2 is a downstream air inflow prevention member 8 and an upstream air inflow prevention member (omitted in the drawing).
And the rear-side air inflow prevention member 10 is disposed at both ends of the shield member 2.
The third embodiment is different from the first embodiment in that the downstream air inflow prevention member 8 is provided.
And the back side air inflow prevention member 10 is integrally formed. This integral formation facilitates the attachment of the air inflow prevention means. The upstream air inflow prevention member 11 used in the first embodiment is not used in the second embodiment. FIG. 5 shows a third embodiment of the air inflow prevention means of the present invention. The second embodiment is characterized in that the downstream air inflow prevention member 8 and the back air inflow prevention member 10 of the first embodiment are integrally formed.
The third embodiment includes a downstream air inflow prevention member 8, a rear air inflow prevention member 10, and an upstream air inflow prevention member 1.
1 is formed integrally. This integral formation facilitates the attachment of the air inflow prevention means. FIG.
FIG. 2 is a perspective view showing a state where the air inflow prevention means according to the first embodiment of the present invention is mounted, and the mounting position and size thereof are perspectively viewed from the back side of the corona discharge device and from the downstream side. is there.

FIG. 7 is a graph showing the effect obtained when a corona discharge device having air inflow prevention means according to the present invention is used. The vertical axis represents the ozone concentration [PPM], and the horizontal axis represents the length [mm] of the corona discharge device in the longitudinal direction. Curve A
3 shows an ozone concentration distribution of a corona discharge device using both the air inflow prevention means and the grid according to the present invention. Curve B
Fig. 3 shows the ozone concentration distribution of a corona discharge device in which the flow of ion wind is changed by providing an insulating shield only at the end of the discharge device without using a grid as disclosed in Japanese Utility Model Publication No. 57-93942. Curve C shows the ozone concentration distribution of the corona discharge device when the above-mentioned insulating shield is not used. In the curve B, it can be seen that the ozone concentration is substantially constant, but the value is high. In the curve C, it is understood that ozone tends to be concentrated in the central portion, and ozone stays inside the corona discharge device, so that ozone has increased as a whole. Further, when an insulating shield is provided at the end of the discharge device to change the flow of the ion wind, the ozone concentration distribution can be made uniform. On the other hand, the curve A according to the present invention shows that the ozone concentration is substantially constant and the value is low.

FIG. 8 shows the results of measuring the charging potential of the image bearing member in the longitudinal direction of the corona discharge device after 100k copies have been made in a dusty environment using a corona discharge device having a grid. is there. The vertical axis indicates the charging potential, and the horizontal axis indicates the length in the longitudinal direction of the corona discharge device. Curve A
Shows the charging potential when the air inflow prevention means of the present invention is used, and curve B shows the charging potential of a conventional corona discharge device without using the air inflow prevention means. As shown by the curve B, in the conventional corona discharge device that does not use the air inflow prevention means, dust that has flowed in from the end of the device adheres to the end of the grid, making it impossible to perform the original charge control and increasing the charge potential. Has been done. On the other hand, as shown by the curve A, in the corona discharge device using the air inflow prevention means of the present invention, the adhesion of dust on the grid is slight, and the charging potential on the image carrier is not affected. It has been shown. FIG. 9 is a graph showing the effect obtained when the corona discharge device having the air inflow prevention means of the present invention is used. The vertical axis indicates the image quality grade, and the horizontal axis indicates the number of copies.

Curve A shows a change in image quality when the corona discharge device having the air inflow prevention means of the present invention is used.
FIG. 1 shows a change in image quality when a conventional corona discharge device as disclosed in Japanese Utility Model Publication No. 57-93942 is used. Compared with the dotted line indicating a level having no problem in the image quality, the curve A shows that the image quality of the present invention is significantly longer than that of the conventional image quality. It should be noted that the same results as those shown in FIGS. 7, 8 and 9 can be obtained for any of the first, second and third embodiments of the present invention. Next, the material of the air inflow prevention member will be described. In the first embodiment regarding the material of the air inflow prevention member, the material has a light shielding property. This is shown in FIG.
Description will be made based on 0. FIG. 10 shows a state in which the air inflow prevention member is viewed from a direction perpendicular to the length direction of the image carrier 7. Only parts necessary for the description of the material of the air inflow prevention member are shown in a simplified manner, and other unnecessary parts are omitted. In FIG. 10, reference numeral 5 denotes a corona wire which is a charging device for applying a charge to the image carrier 7, and 21 denotes an image carrier 7
, A cleaning device for removing toner, 25 a blade provided on the cleaner device for removing toner remaining on the image carrier, and 27 a static eliminator for removing electric charges remaining on the image carrier. A lamp 29 indicates an air inflow prevention member that is generally expressed.

In FIG. 10, when light from the neutralizing lamp 27 leaks to the corona wire 5, when charging the image carrier 7, the charging operation by the corona wire 5 and the neutralizing operation by the neutralizing lamp 27 occur simultaneously, and a desired stable state is obtained. The charging potential (desired potential) cannot be obtained. Therefore, in order to prevent the light from the static elimination lamp 27 from leaking, the air inflow prevention member 2 is required.
9 must be made of a member having a light-shielding property. FIG.
1 indicates the potential of the image carrier with respect to the light transmittance. Here, “having a light-shielding property” means that when the potential of the image carrier is expressed as a function of the light transmittance as shown in FIG. 11, a predetermined light transmittance is set to obtain a minimum desired potential. It is. In this embodiment, the minimum desired potential can be obtained when the light transmittance is 20%.
% Or less is applicable. In addition, the light transmittance is LED
When the illuminance of the leaked light is measured with the illuminance of the light source (wavelength: 450 to 600 nm) of 500 Lx or more and the air inflow prevention member is interposed, the illuminance is indicated by the ratio of the illuminance of the light source to the illuminance of the leaked light. For example, black PET (polyethylene terephthalate) can be used as a member having light-shielding properties. A second embodiment of the material of the air inflow prevention member is that the material has insulating properties. This will be described with reference to FIGS.

FIG. 12 shows a case where the air inflow prevention member 29 is made of a conductive member. Each component is the same as in FIG. 10, and a description thereof will be omitted. Arrows 31 indicate lines of electric force generated from the corona wire 5, and the number of the lines schematically indicates the density. FIG. 13 shows a case where the air inflow prevention member 29 is made of an insulating member, and other components are the same as those in FIG. Arrows 33 indicate lines of electric force generated from the corona wire 5, and the number of the lines schematically indicates the density. Comparing FIG. 12 with FIG. 13, the density of the lines of electric force traveling from the corona wire 5 to the image carrier 7 is such that the air inflow prevention member made of an insulating member is better than the air inflow prevention member made of a conductive member. large. This is because, when the air inflow prevention member is made conductive, the density of the lines of electric force required for the image carrier 7 to be charged is reduced, and as a result, the potential at the image carrier 7 reaches the desired potential. Means not reaching. Therefore, the air inflow prevention member needs to be formed of a member having an insulating property. For example, PET can be configured as the air inflow prevention member. A third embodiment of the material of the air inflow prevention member is that the material has flame retardancy.

The corona wire has a high voltage (for example, 5K).
Since V) is applied, a spark discharge occurs between the corona wire and the air inflow prevention member. This spark discharge may cause a fire or the like. Therefore, from the viewpoint of safety, the air inflow prevention member needs to be formed of a member having flame retardancy. For example, polypropylene can be used as a member having flame retardancy. The discharge products cause deterioration of the image carrier, and as a result, it becomes impossible to obtain a good image. Therefore, it is necessary to eliminate discharge products. Ni (nickel), activated carbon, or the like can eliminate the discharge products by absorbing or chemically changing the discharge products. Therefore, by configuring the air inflow prevention member with Ni or the like, the deterioration of the image carrier is reduced. Can be prevented. The same effect can be obtained by coating the surface of the air inflow prevention member with Ni or the like. Next, an embodiment of the present invention relating to attachment / detachment of the air inflow prevention member and fixation thereof will be described. FIG.
FIG. 4 is a first embodiment of the present invention relating to attachment / detachment and removal of an air inflow prevention member, and is a view showing a state when an air inflow prevention member 13 is attached to a shield member 2.

In FIG. 14, reference numeral 3 denotes an attachment end block for attaching a corona wire to the shield member 2,
The air inflow prevention member 13 is an air inflow prevention member according to the third embodiment of the present invention shown in FIG. 40a, 40b, 4
Reference numerals 0c and 40d denote cylindrical convex positioning means provided on the side surface of the air inflow prevention member 13, 41a (not shown),
41b, 41c (not shown) and 41d are end blocks 3
, A cylindrical concave positioning means provided on the
Reference numeral 2b denotes a rectangular parallelepiped convex positioning means provided on the back surface of the air inflow prevention member 13, and 43a and 43b denote openings provided on the back surface of the shield member 2. Under such a configuration, the air inflow prevention member 13 is attached to the shield member 2 as follows. The air inflow prevention member 13 is gradually approached to the shield member 2 and the air inflow prevention member 13
Immediately before the end of the member comes into contact with the end of the shield member 2, the air inflow prevention member 13 is slightly outwardly spread outward. Then, the air inflow prevention member 13 is further moved closer to the shield member 2 so that the air inflow prevention member 13 overlaps the shield member 2. Positioning means 40a for the air inflow prevention member 13,
40b, 40c, 40d are positioning means 41a (not shown), 41b, 41c (not shown) of the end block 3,
When reaching the respective positions of 41d, the applied force is released, and the positioning means 40a, 40b, 40c, 40
d is the positioning means 41a (not shown), 41b, 41c
(Not shown) and 41d. At this time, the other positioning means 42a, 42b are opened 43a,
43b.

As described above, since the positioning means 40a and the like are inserted into the positioning means 41a (not shown) and the like, the inside of the side surface of the air inflow prevention member 13 having the positioning means 40a and the like is outside the shield member 2. , The vertical movement of the air inflow prevention member 13 is prevented. The positioning means 42a presses the opening 43a in the direction of the one end block 3, and the opening 42b presses the opening 43b in the direction of the other end block 3 to engage with the opening 43b. Movement in the direction is prevented. When removing the air inflow prevention member 13, the reverse of the case of attaching the air inflow prevention member 13 may be performed. That is, a slight force is applied to the air inflow prevention member 13 to spread it outward, and the positioning means 4
1a (not shown), etc., positioning means 40
a and the like may be taken out separately. As described above, the positioning means 40a and the like are made convex, and the positioning means 41a
(Not shown) and the like are made concave,
The same effect can be obtained by making the shape of Oa or the like concave, and making the positioning means 41a (not shown) or the like convex. FIG.
Reference numeral 5 denotes a second embodiment of the present invention relating to attachment / detachment of the air inflow prevention member and fixing thereof, in which the air inflow prevention member is used as it is as a shield member.

In FIG. 15, 3 is an end block, 13
Are air inflow prevention members (strictly different from the air inflow prevention member 13 shown in FIG. 14 but are referred to as air inflow prevention members for convenience, and are denoted by reference numeral 13), 52a, 52b, and 52
c and 52d denote cylindrical convex positioning means provided on the end block 3, and 53a, 523, 53c and 53d denote U-shaped concave positioning means provided on the air inflow prevention member 13. Under this configuration, the air inflow prevention member 13 and the end block 3 are attached as follows. One end block 3 is moved horizontally in the direction of the air inflow prevention member 13, and the convex positioning means 52a and 52b are inserted into the concave positioning means. Continue to insert until it stops completely. Similarly, one end block 3 is inserted into the air inflow prevention member 13. Air inflow prevention member 13
When separating and removing the end block 3 from the end block 3, the operation opposite to the operation of attaching the end block 3 may be performed. That is, the end block 3 may be moved horizontally from the air inflow prevention member 13 in a direction away from the air inflow prevention member 13. By such a simple operation, the air inflow prevention member 13 and the end block 3 can be attached and detached, and accurate positioning can be performed. In addition, it is possible to prevent the air inflow prevention member from moving up, down, left, and right.

In the second embodiment, the positioning means 52a and the like of the end block 3 are made convex and the positioning means 53a and the like of the air inflow prevention member 13 are made concave. Making the means 52a etc. concave,
It is also possible to make the positioning means 53a and the like of the air inflow prevention member 13 convex.

[0021]

According to the present invention, it is possible to prevent the flow of dirty air containing a lot of dust from the axial end of the discharger, reduce the contamination of the grid, prevent the potential from rising, and perform uniform charging. Will be able to do it. Therefore, a high-quality image can be obtained. In addition, it is possible to reduce contamination of the wire shield and the corona wire, and to perform uniform discharge. Further, the ozone concentrated in the central portion is dispersed, and the ozone can be forcibly exhausted by the ion wind from the back surface, so that deterioration due to the ozone can be prevented. Further, according to the present invention, the air inflow prevention member can be easily attached and removed. Further, the air inflow prevention member can be accurately attached to a predetermined position, and can be prevented from moving in the vertical and horizontal directions.

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional corona discharge device, showing a direction in which wind and ion wind flowing from the outside flow.

FIG. 2 is a perspective view of a corona discharge device having a first embodiment of the air inflow prevention means of the present invention, showing a direction in which wind and ion wind flowing from the outside flow.

FIG. 3 is an assembled view of the first embodiment of the air inflow prevention means of the present invention.

FIG. 4 is a view showing a second embodiment of the air inflow prevention means of the present invention.

FIG. 5 is a view showing a third embodiment of the air inflow prevention means of the present invention.

FIG. 6 is a perspective view showing a state in which the first embodiment of the air inflow prevention means of the present invention is mounted, and the mounting position and size thereof are perspectively viewed from the back side of the corona discharge device and from the downstream side. is there.

FIG. 7 is a graph showing an ozone concentration when a corona discharge device having an air inflow prevention unit according to an embodiment of the present invention is used.

FIG. 8 is a graph showing a charging potential when a corona discharge device having air inflow prevention means according to an embodiment of the present invention is used.

FIG. 9 is a graph showing deterioration of an image carrier when a corona discharge device having air inflow prevention means according to an embodiment of the present invention is used.

FIG. 10 shows a state in which the air inflow prevention member is viewed from a direction perpendicular to the length direction of the image carrier.

FIG. 11 shows the potential of the image carrier with respect to the light transmittance.

FIG. 12 shows a case where the air inflow prevention member is made of a conductive member.

FIG. 13 shows a case where the air inflow prevention member is made of an insulating member.

FIG. 14 is a first embodiment of the present invention relating to attachment / detachment of an air inflow prevention member and fixation thereof.

FIG. 15 is a second embodiment of the present invention relating to attachment / detachment of the air inflow prevention member and fixing thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Corona discharge device 2 Shield member 3 End block 3a End block electrode support part 3b Arc shield 4 Power supply terminal 5 Corona wire 6 Grid 7 Image carrier 8 Air inflow prevention member (downstream side) 9 Air inflow prevention member (Block 3) 10 Air inflow prevention member (back side) 11 Air inflow prevention member made of light-shielding mylar (upstream side) 12 Air inflow prevention member (integration of downstream side and back side) 13 Air inflow prevention member (upstream) 14) Spring for grid support

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-119585 (JP, A) JP-A-4-181964 (JP, A) JP-A 5-64860 (JP, U) JP-A 5-119860 173748 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/02

Claims (6)

(57) [Claims] 1. A corona discharge device having a corona wire means for generating a corona charge so as to charge an image carrier, a shield means for shielding the corona wire means, and a grid on which a wire or a plate is stretched. Air inflow prevention means for preventing the inflow of air from the air supply means is provided with a longitudinal end block of the shield means and the air inlet .
A corona discharge device provided between the lids . 2. The corona discharge device according to claim 1, wherein said air inflow prevention means is a light-shielding member. 3. The corona discharge device according to claim 1, wherein said air inflow prevention means is a flame-retardant member. 4. The corona discharge device according to claim 1, wherein said air inflow prevention means is an electrical insulator. 5. The corona discharge device according to claim 1, wherein the air inflow prevention means is made of a substance that absorbs or chemically changes a product generated by the discharge. 6. The air inflow prevention means has positioning means, and the end of the shielding means also has positioning means,
2. The corona discharge device according to claim 1, wherein the positioning means of the air inflow prevention means engages with the positioning means at the end of the shield means so that the air inflow prevention means can be attached and detached.