JPH09171283A - Corona electric discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corona electric discharge device constituted so that the tip part of a projecting electrode is not damaged and the interior of an image forming device is easily maintained. SOLUTION: In the corona electric discharge device 1, a supporting member 3 holding the projecting electrode 2 is held so that it can be moved in the carrying direction of a paper (direction shown by an arrow). When the discharge device 1 is not fitted to an image forming device body, the tip part of the electrode 2 is not exposed because the electrode 2 is protected by the lower part of a protection part 5b. On the contrary, when the discharge device 1 is fitted to the image forming device body, it can be used as the normal electric discharge device because the supporting member 3 is moved and the tip part of the electrode 2 is exposed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a corona discharge device,
More specifically, the present invention relates to a corona discharge device used as a charging charger, a transfer charger, a separation charger, etc. in an image forming apparatus using an electrophotographic system such as a copying machine, a printer and a facsimile.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus using an electrophotographic system such as a copying machine, a printer and a facsimile, many corona discharge devices have been used as a charging charger, a transfer charger, a separation charger and the like.

As a corona discharge device used as a charger as described above, there are a corona discharge device using a wire electrode as a discharge electrode and a device using a protruding electrode. Among these, as the latter protruding electrode, various shapes such as a wedge shape (a), a needle shape (b), a needle shape (c), and a sawtooth shape (d) are proposed, as shown in FIG. Since such a protruding electrode produces a smaller amount of ozone than a wire electrode, it has been widely used in recent years.

However, NOx is generated at the tip of the protruding electrode during discharge. In a high humidity environment, NOx combines with moisture in the air to generate nitric acid, attack the electrodes, and cause a non-uniform electric field due to discharge. If the electric field due to discharge is non-uniform, uneven charging occurs on the photoconductor, and a good image cannot be obtained.

Therefore, in the corona discharge device using the protruding electrode, it is necessary to remove it from the main body of the image forming apparatus to which it is attached for maintenance or to replace it appropriately.

However, since the tip of the protruding electrode is always exposed, when the user or a service person replaces the tip, the tip of the electrode may accidentally come into contact with the tip of the electrode, or may come into contact with another member during mounting. Could damage the electrodes.

With respect to the above problems, Japanese Patent Laid-Open No. 5-4
Japanese Patent Laid-Open No. 6000 proposes a corona discharge device in which a cover is provided to cover the tip of the protruding electrode, and the cover can be released after the corona discharge device is attached to the main body of the image forming apparatus.

[0008]

However, in the corona discharge device described in the above publication, when it is attached to the main body of the image forming apparatus, the distance between the electrode tip and the photoconductor facing the electrode tip is small, It may be difficult to provide a cover. Further, even if the cover can be provided, since the space for disposing is small, there is a possibility that the electrode tip portion or the surface of the photoreceptor may be damaged by the cover when the corona discharge device is attached to the image forming apparatus main body.

Further, in this corona discharge device, after the device is attached to the main body of the image forming apparatus, the inside of the main body of the image forming apparatus is opened for maintenance such as paper jam processing, and the corona discharge of the photoconductor is performed. When exchanging consumables such as a photoconductor and a toner bottle around the apparatus, the tip of the protruding electrode was left exposed. Therefore,
There is a risk that the operator may accidentally contact the tip of the electrode.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a corona discharge device capable of easily maintaining the inside of an image forming apparatus without damaging the tip of the protruding electrode.

[0011]

In order to achieve the above object, a corona discharge device according to claim 1 is a corona discharge device having a projecting electrode and supported inside an image forming apparatus. A protection member that protects the electrode tip of the protruding electrode so that the electrode tip is not exposed, a support member that supports the protruding electrode, and a mounting member that is provided on the support member and that is provided on the image forming apparatus side. When the engaging portion that engages with, and the engagement between the engaging portion and the mounting member are released,
A moving mechanism that moves the support member to a position where the electrode tip of the protruding electrode is protected by the protection member.

A corona discharge device according to claim 2 is
The corona discharge device according to claim 1, wherein the engagement between the engaging portion and the attachment member is disengaged when the electrode tip of the protruding electrode is separated from the surface to be discharged.

The corona discharge device according to claim 3 is
The corona discharge device according to claim 1, wherein the engagement between the engaging portion and the mounting member is released when the corona discharge device itself is detached from the image forming apparatus main body.

The corona discharge device according to claim 4 is
The corona discharge device according to claim 1, wherein the engagement between the engaging portion and the mounting member is released when the inside of the image forming apparatus is opened.

In the corona discharge device of the present invention configured as described above, when the engaging portion provided on the supporting member of the protruding electrode and the mounting member provided on the image forming apparatus side are disengaged from each other. Since the support member moves to a position where the electrode tip portion is protected by the protection member, the electrode tip portion is not exposed.

[0016]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Configuration and Operation of Image Forming Apparatus FIG. 15 is a schematic configuration diagram of an analog copying machine 100 incorporating a corona discharge device according to the present invention. A photoconductor drum 101 is arranged in the center of the analog copying machine 100, and the photoconductor drum 101 is clockwise (in the direction of the arrow in the figure).
It can be rotated. A charger 102 is arranged above the photoconductor drum 101. Photoconductor drum 1
A cleaner unit 1 having a developing device 103 containing a two-component developer composed of toner and a magnetic carrier, a transfer separation charger 104, and a blade 106 in the order of 01 from the charger 102 to the photosensitive drum 101 in the order of rotation from the charger 102.
07 is arranged. Of these, the photosensitive drum 101,
Charging charger 102, developing device 104, cleaner unit 10
Reference numeral 7 constitutes an imaging cartridge 108 integrated by a case member, and the analog copying machine 100
It is detachably supported by the frame. Further, the transfer / separation charger 104 is detachably held in a groove portion 105 provided in the lower portion of the main body 100, as described later in detail.

At the top of the analog copying machine 100 is an image reading section 109. The image reading unit 109 is a well-known unit including a lamp for irradiating an original, a mirror, and the like, and the image reading unit 109 is fixed and the original moves on the image reading unit 109.

In the lower part of the analog copying machine 100,
A transfer material transport unit 110 is arranged, and from the right side in the drawing,
Paper feed unit 111, paper feed roller 112, transport roller 113,
Registration roller 114, transfer separation charger 10 described above
4, fixing roller 115, discharge roller 116, discharge unit 11
7 are arranged. Each of the transport roller 113, the registration roller 114, the fixing roller 115, and the discharge roller 116 is composed of a pair of rollers.

Further, as shown in FIG. 16, the main body 100 of the analog copying machine can be separated and opened into an upper part for holding the imaging cartridge 108 and a lower part for holding the carrying part 110. The top and bottom of body 100 are typically shown in FIG.
5 is locked and integrated by the engagement of the engaging portion 118, but when the lock is released and the claws 118a and 118b of the engaging portion 118 are disengaged as shown in FIG. 16, the fulcrum 11
The upper part is lifted upward with 9 as an axis, and the inside is opened. Hereinafter, such a mechanism is referred to as a clamshell, and a state in which the upper portion and the lower portion are opened is referred to as a clamshell opening.

In the analog copying machine main body 100 having the above-described structure, when a start button (not shown) is pressed, the photosensitive drum 101 is rotated and the charger 10 is charged.
By 2, the surface of the photoconductor drum 101 is uniformly charged. Next, the image reading unit 109 is moved along with the movement of the document table.
The read original image is irradiated onto the photosensitive drum 101 as exposure light, and an electrostatic latent image is formed on the photosensitive drum 101.
Formed on the surface. Toner is supplied to the electrostatic latent image from the developing device 103 to form a toner image. On the other hand, the paper feed unit 1
From 11, the transfer material such as paper is conveyed to the registration roller 114 by the paper feed roller 112 and the conveyance roller 113. The registration roller 114 starts rotating in synchronization with the rotation of the photoconductor drum 101 and supplies the transfer material to the photoconductor surface. At this time, the toner image on the photosensitive drum 101 is
It is transferred to the transfer material by the transfer separation charger 104. The toner image is fixed on the transfer material by the fixing roller 115 by heat and pressure, and is discharged to the discharging portion 117 by the discharging roller 116. On the other hand, the toner remaining on the surface of the photosensitive drum 101 after the transfer is further scraped off by the blade 106 as the photosensitive drum 101 further rotates and is cleaned by the cleaner unit 10.
Recovered to 7. With the above steps, one image forming process is completed.

Structure and Operation of Corona Discharge Device 1. Keep the tip of the protruding electrode
Embodiments to be Protected First, the first to third embodiments in which the tip end portion of the protruding electrode is protected by the protective portion when the corona discharger is removed from the analog copying machine will be described.

[First Embodiment] FIGS. 1 and 2 show a corona discharge device 1 according to a first embodiment of the present invention. The corona discharger 1 of this embodiment is used as the transfer / separation charger 104, and is arranged in the paper transporting section under the analog copying machine 100 described above.

FIG. 1 shows the corona discharge device 1 removed from the analog copying machine 100. The corona discharger 1 includes a shield member 5 having an opening 5a in the upper part of the drawing and having a substantially U-shaped cross section, two blocks 4 provided at both ends inside the shield member 5, and a sheet formed by a block 4. The support member 3 is movably supported in the transport direction (arrow direction in the figure), and the protruding electrode 2 is fixed on the support member 3.

The opening 5a of the shield member 5 has a protective portion 5b formed by extending and bending a part of one side surface to cover a part of the opening 5a. This protection part 5b
When the corona discharger 1 is removed from the analog copying machine 100, the tip of the protruding electrode 2 has an opening 5a.
It is to protect it from being exposed. Further, the support member 3 includes plate-shaped both end portions 3d forming a part of a moving mechanism described later inside the block 4 and electrode support portions 3e extending in the longitudinal direction and connecting both end portions, and both end portions 3d.
Is formed with a slope 3c on the end face side.

FIG. 2 is a view showing how the corona discharger 1 is attached to the groove 105 provided in the analog copying machine 100. The groove 105 is provided with a mounting guide portion 6. The tip 6a of the mounting guide 6 is the groove 1
The inside of 05 has a pentagonal prism shape with a part of a rectangular parallelepiped cut off. The slope 6c of the pentagonal prism has substantially the same inclination angle as the slope 3c of the support member 3 described above. Further, a mounting portion 6b extends to the front side of the drawing in the mounting guide portion 6, and the mounting portion 6b is mounted on the analog copying machine 100.
It is fixed to. Further, the mounting guide portion 6 and the groove portion 1
The side surface of 05 has a gap 6d which is slightly larger than the thickness of the shield member 5 of the corona discharge device 1.

In FIG. 2, the corona discharge device 1 is attached to the groove portion 1.
In order to attach it to 05, insert it in the direction of arrow b in the figure,
The support member 3 moves in the direction of the arrow a in the figure, and the tip of the protruding electrode is exposed from the opening 5 a of the shield member 5.

FIG. 3 is a sectional view of the corona discharge device 1.
3, FIG. 3A shows a cross section in the AA ′ direction in FIG. 1, and FIG. 3B shows a cross section in the BB ′ direction in FIG. Also,
The left side of each figure shows that the corona discharge device 1 is an analog copying machine 10.
The state of being attached from 0 is shown, and the right figure shows the state of being attached.

In FIG. 3, a part of the supporting member 3 and a part of the block 4 constitute a moving mechanism M1 for movably holding the supporting member 3. The moving mechanism M1 is provided on the support member 3 and a guide portion 4a provided on the block 4 for guiding the support member 3 so that the support member 3 can move only in the sheet conveying direction, a protruding spring guide 4b inside the guide portion 4a. A guide hole 3a larger than the outer diameter of the spring,
It consists of a spring 7.

In such a structure, when the corona discharge device 1 is inserted in the direction of arrow b in FIG. 2 for mounting in the groove portion 105, the shield member 5 of the corona discharge device 1 is guided to both side surfaces of the groove portion 105, and eventually. The slope 3c of the support member 3 and the slope 6c of the mounting guide portion 6 are in contact with each other. Since the slope 3c and the slope 6c have substantially the same inclination, the support member 3 is smoothly guided by the mounting guide portion 6 and moves in the direction of arrow a as it is inserted in the direction of arrow b. At this time, the side surface of the shield member 5 on the side where the protective portion 5b is provided is inserted into the gap 6d formed between the groove portion 105 and the mounting guide portion 6. When the corona discharger 1 is completely inserted into the groove 105, the support member 3 completes its movement, and the tip of the protruding electrode 2 on the support member 3 is exposed through the opening 5a of the shield member 5.

The above operation will be described with reference to the sectional view of FIG. 3. In the state where the corona discharger 1 is attached to the groove portion 105 (the state shown on the right side of FIGS. 3A and 3B), the groove portion 105 is as described above. Mounting guide portion 6 and support member 3 provided on the
When the support member 3 is pressed, the support member 3 is pressed and the two springs 7 are compressed.
To the side where the protective portion 5b is not provided. As a result, the protruding electrode 2 is located at the center of the shield member 5. In this way, the supporting member 3 is fixed at a predetermined position by the repulsive force of the spring 7, so that the position of the protruding electrode 2 is also fixed at the center, and the tip of the protruding electrode is exposed from the opening 5a. Become.

On the contrary, when the corona discharger 1 is detached from the groove portion 105 (the state shown in the left diagram of FIGS. 4A and 4B), the support member 3 includes the support member 3 and the attachment guide portion spring 7. Is repulsively moved to the side surface on the side where the protective portion 5b is located. That is, when the corona discharge device 1 is pulled out from the groove portion 105, the support member 3 and the mounting guide portion 6 are disengaged and moved in the direction opposite to the arrow a direction, and the tip end portion of the protruding electrode 2 is protected by the protection portion 5b. Return to the bottom of. In this state, the protruding electrode 2 is located below the protective portion 5b of the shield member 5,
The tip portion is not exposed from the opening 5a.

As described above, the corona discharger 1 of the first embodiment has the groove portion 105 provided in the analog copying machine 100.
When the support member 3 is removed from, the projecting electrode 2 is forcibly moved below the protective portion 5b provided on the shield member 5 by the movement of the support member 3. Therefore, for maintenance, etc.
Even if the corona discharger 1 is removed from the analog copying machine 100, a user or a service person does not accidentally contact the electrode tip.

[Second Embodiment] Next, a corona discharge device 11 according to a second embodiment will be described. The corona discharge device 11 of the second embodiment is a modification of the corona discharge device 1 described above, and is similarly used as the transfer separation charger 104.

FIG. 4 shows the corona discharge device 11 according to the second embodiment of the present invention at the same position as the corona discharge device 1 shown in FIG. 3 (the AA 'direction and the BB' direction in FIG. 1). It is sectional drawing which cut | disconnected. Similarly to FIG. 3, FIG. 4 shows the state where the corona discharge device 11 is removed from the main body 100, and the left diagram shows the state where the corona discharge device 11 is attached to the main body 100.

In FIG. 4, the corona discharge device 11 is similar to the corona discharge device 1 of the first embodiment, and the protruding electrode 12, the support member 13, the shield member 15, and the block 1 are provided.
It is composed of 4. Part of block 14 and support member 13
A part of the above constitutes a moving mechanism M2 for movably holding the support member 13. The moving mechanism M2 includes a guide portion 14a provided on the block 14 so that the supporting member 13 can move only in the sheet conveying direction, a protruding spring guide 13a on the supporting member 13, a spring 17, and a guide portion 14.
It has a guide hole 14b which is provided inside a and is larger than the outer diameter of the spring 17. Further, a trapezoidal projection 13b is provided at one end of the support member 13, and a hole portion 15c corresponding to the size of the projection 13b is provided on the wall surface of the shield member 15 facing the projection 13b. Further, the shield member 15 has a protection portion 15b formed by bending a part of its side surface to protect the tip of the protruding electrode 11.

FIG. 5 shows a groove portion 105b corresponding to the corona discharge device 11 provided in the analog copying machine 100. The mounting guide portion 16 is provided on one wall surface of the groove portion 105b.
Is provided. On the front side of the mounting guide section 16,
There is a slope portion 16a formed by bending the guide portion 16.

When the corona discharge device 11 is removed from the groove 105b (the state shown on the left in FIGS. 4A and 4B), the support member 13 is forced to be protected by the repulsive force of the spring 17. The protrusion 13b is moved to a side surface on a certain side, and the protrusion 13b projects outside from the hole 15c of the shield member 15. In this state, the protruding electrode 12 is
Since the shield member 15 is located below the protective portion 15b, the tip portion is not exposed through the opening 15a.

In a state where the corona discharger 11 is attached to the groove portion 105b (a state shown on the right side in FIGS. 4A and 4B), the mounting guide portion 16 provided on the groove portion 105b and the projection provided on the support member 13 are provided. The protrusion 13b is housed inside the shield member 15 by the contact of 13b,
The support member 13 moves in the sheet conveying direction, and the protruding electrodes 2
Will be located at the center of the shield member 15.
At this time, the protrusion 13b of the support member 13 and the contact portion of the inclined surface portion 16a of the attachment guide portion 16 are smoothly brought into contact with each other. The corona discharge device 11 is used as the analog copying machine 100.
Since the support member 13 is fixed at a predetermined position in the state of being attached to, the position of the protruding electrode 11 is also fixed at the center, and the tip portion is exposed from the opening.

As described above, the corona discharger 11 of the second embodiment also has the groove portion 105 provided in the analog copying machine 100.
When removed from b, the projecting electrode 12 is provided on the shield member 15 by the movement of the support member 13
Forced to move below. Therefore, even if the corona discharger 11 is removed from the analog copying machine 100 for maintenance or the like as in the first embodiment, a user or a service person does not accidentally contact the electrode tip.

[Third Embodiment] FIG. 6 is a sectional view of a corona discharge device 21 according to a third embodiment of the present invention, taken along the longitudinal center of a shield plate 25. In this example, the corona discharge device 21 is also used as the transfer separation charger 104.

The corona discharge device 21 is roughly the projecting electrode 2
2, a support member 23 supporting the projecting electrode 22, a block 24 at both ends of the support member 23 for movably holding the support member 23, and a shield member around the block 24 and the support member 23. 25.
A part of the block 24 and a part of the support member 23 form a moving mechanism M3. The moving mechanism M3 includes a support member 23.
It is a guide portion 27 provided on the block 24 so as to be movable. The support member 23 has trapezoidal projections 23a at both ends, and a hole 25c is provided at a position facing the projection 23a at the bottom of the shield member 25.

FIG. 7 is a sectional view of the corona discharge device 21 in the paper conveyance direction. The support member 23 is covered with a protection member 25b. The protective member 25b has an elongated hole formed in the upper portion thereof in the size of the protruding electrode 22.

FIG. 8 shows a corona discharge device 2 of the third embodiment.
The groove portion 105c corresponding to 1 is shown. Groove 105c
An attachment guide portion 26 is provided on the bottom surface of the. At the front side of the attachment guide portion 26, the attachment guide portion 2
Slope portion 26a formed by bending the tip of 6 downward
There is.

FIG. 9 is an enlarged view of the protruding electrode 22. The left view is attached to the main body 100, and the right view is the groove portion 10.
The state removed from 5c is shown. As mentioned above, the third
When the corona discharge device 21 of the embodiment is removed, the support member 23 moves downward due to its own weight, and the projection 23 is projected from the hole 5c.
a protrudes from the state shown in the left diagram of FIG. 10 to the state shown in the right diagram. At this time, since the periphery of the support member 23 is covered with the protective member 25b, the tip end portion of the protruding electrode 22 is not exposed. On the contrary, since the support member 23 is pushed up when it is attached to the main body, the projection 2 protruding from the hole 5c
3a and an inclined surface portion 26a provided on the attachment guide portion 26
Contact each other and push the support member 23 upward. Therefore, the tip of the protruding electrode 22 is exposed.

As described above, the corona discharger 21 of the third embodiment also has the groove 10 provided in the analog copying machine 100.
When removed from 5c, the tip of the protruding electrode 22 is covered with the protective member 25b by the movement of the support member 23. Therefore, even if the corona discharger 21 is removed from the analog copying machine 100 for maintenance or the like as in the first and second embodiments, a user or a service person does not accidentally contact the electrode tip. Furthermore, the moving mechanism M3
Since it is due to its own weight, the device configuration can be simplified. Of course, in order to further improve safety, a leaf spring, a spring, or the like may be attached to the moving mechanism M3 and the supporting member 23 may be forcibly pushed down.

The corona discharge device 21 of the third embodiment described above.
In the above, a sealing material, a brush or the like may be attached to the tip of the protective member 25b in order to clean the protruding electrode 22. By attaching such a cleaning member, the protruding electrode 2
2 can be prevented from deterioration with time, and more uniform discharge can be performed.

In addition, with respect to the first to third embodiments, the same effect can be obtained for the corona discharge device attached to the imaging cartridge 108. That is, the imaging cartridge 108
By providing the above-described groove portions 105, 105b, 105c, etc., it is possible to move the protruding electrodes in conjunction with each other when the corona discharge device is removed from the imaging cartridge 108.

2. When you open the clamshell,
Embodiments for Protecting the Tip of the Pole Next, the fourth and fifth embodiments for protecting the tip of the protruding electrode when the clam shell is opened will be described.

[Fourth Embodiment] FIG. 10 shows a corona discharger 31 (upper drawing) and a supporting member 33 (lower drawing) for supporting the projecting electrodes 32 of the fourth embodiment. In this example, the corona discharger 31 is also used as the transfer separation charger 104. In the upper diagram of FIG. 10, the corona discharge device 31 includes a protruding electrode 32, a support member 33 that supports the protruding electrode 32,
The shield member 35 has an opening 35a on the side of the photosensitive drum 101. In FIG. 10, the support member 3
3 has a rotary shaft 33a on the side opposite to the side supporting the protruding electrode 32, and the support member 33 is rotatably supported by the shield plate 35 about the rotary shaft 33a.
One end of the rotary shaft 33a is extended to project to the outside of the shield plate 35, and a flat plate-shaped lever 33b is provided at the extended end. Lever 3
A torsion coil spring 33c is attached to the rotary shaft 33a near 3b.
Is provided. One end of the torsion coil spring 33c is fixed to the rotating shaft 33a, and the other end is fixed to the main body 10.
It is fixed to 0.

FIG. 11 is a schematic view showing how the corona discharge device 31 is attached to the analog copying machine 100. As described above, the analog copying machine 100 is divided into an upper part and a lower part by the clam shell and the inside can be opened. The corona discharger 31 is attached to the lower part of the analog copying machine 100, and as shown in the drawing, the rotating shaft 33a.
The lever 33b portion can rotate around. A mounting guide portion 36 is fixed at a position facing the lever 33b on the upper portion of the analog copying machine 100.

FIG. 12 is a schematic view showing the moving mechanism M4 of the corona discharge device 31. The moving mechanism M4 includes the support member 3
3 rotation shaft 33a, lever 33b, mounting guide portion 36
Consists of In the left view of FIG. 12, in a normal state, the attachment guide portion 36 contacts the lever portion 33b, and the support member 33 is fixed so that the tip end portion of the protruding electrode 32 is exposed. On the other hand, as shown in the right diagram of FIG. 12, when the inside of the main body is opened by opening the clamshell, the mounting guide portion 3
6 and lever portion 33b come out of contact with each other, and the torsion coil spring 3
By the repulsive force of 3c, the support member 3 is centered around the rotating shaft 33a.
3 rotates, and the tip of the protruding electrode 32 moves to a position where it is not exposed. At this time, as shown in FIG.
Due to the protective member 35b provided at the end, the tip end portion of the protruding electrode 32 is not exposed.

As described above, in the corona discharge device 31, the operator does not expose the tip end of the protruding electrode 32 when the operator opens the inside of the main body to perform work such as paper jam treatment or replacement of the photoconductor. Move to position. Therefore, the user or the service person does not come into contact with the tip end portion of the protruding electrode 32, so that the tip end portion of the protruding electrode is not damaged and the work can be performed safely. On the contrary, when the work is completed and the main body is returned to the normal state, the projecting electrodes 32 are returned to their original positions again, so that the device can be used as a normal corona discharge device.

[Fifth Embodiment] Next, a corona discharge device 41 of a fifth embodiment will be described with reference to FIG. The corona discharge device 41 of the fifth embodiment is a modified example of the corona discharge device 31 described above, and the main configuration is substantially the same as that of the fourth embodiment described above. Therefore, description of parts other than those described below will be omitted. FIG. 13 shows a corona discharge device 41.
It is a schematic diagram of the moving mechanism M5. In FIG. 13, the periphery of the support member 43 that supports the protruding electrode 42 is surrounded by the protection member 4
4 is provided, and the support member 43 is movable inside the protection member 44 in the arrow direction in the figure. In addition, an opening 45 a through which the tip of the protruding electrode 42 is exposed is provided above the protective member 44. Further, the pin 43 a is projected laterally from the support member 43, and the lever member 47
Is engaged with the long hole portion 47a. The pin 43a can move in the elongated hole portion 47a. The lever member 47 is rotatably supported on the outside of the protection member 44 by a rotary shaft 47b, and has a protruding portion 47c formed by bending the opposite side of the elongated hole portion 47a.

As shown in the left diagram of FIG. 13, when the main body 100 is in a normal use state, the protruding portion 47c and the mounting guide portion 36 are provided.
And the pin 43a is positioned at the farthest portion of the elongated hole portion 47a from the rotation shaft 47b, so that the support member 43 is fixed to the upper portion and the tip portion of the protruding electrode 42 is exposed. on the other hand,
As shown on the right side of FIG. 13, the clamshell is opened and the main body 100 is opened.
When the work is carried out inside, the contact between the protruding portion 47c and the mounting guide portion 36 is released, the pin 43a moves inside the elongated hole portion 47a, and the supporting member 43 descends and the protruding electrode 42 is housed inside the protective member 44. Therefore, the tip is not exposed.

Therefore, the corona discharge device 41 of the fifth embodiment can obtain the same effect as the corona discharge device of the fourth embodiment.

The corona discharge devices of the fourth and fifth embodiments are not only those that move in conjunction with the opening of the clam shell of the image forming apparatus main body, but also a mechanism that opens the exterior member of the main body for maintenance inside the main body. Generally applicable.

[Modifications of Embodiments] The corona discharge device according to the present invention as described above is not limited to the configuration shown in the embodiments, and can be appropriately modified within the scope of the invention. Is. For example, the corona discharge device may be applied not only to the transfer separation charger but also to various corona discharge devices used in an image forming apparatus using an electrophotographic method, such as a charging charger and a pre-cleaner charger. Further, the analog copying machine 100 may be another image forming apparatus such as a digital copying machine or a printer.

[0058]

As described above, in the corona discharge device according to the present invention, when the engagement portion provided in the corona discharge device and the attachment portion provided on the image forming apparatus side are disengaged, The support member moves and moves to a position where the tip of the protruding electrode is not exposed.

Therefore, in the disengaged state, the electrode tip portion of the projecting electrode is not exposed, so that the operator does not touch the tip portion of the projecting electrode. Therefore, the operator does not damage the tip of the protruding electrode during maintenance.

Therefore, when the corona discharge device according to the present invention is applied to an image forming apparatus using an electrophotographic system such as a copying machine, a printer and a facsimile, it is possible to realize an image forming apparatus which can be easily maintained. Further, since the tip end portion of the protruding electrode is not damaged, the corona discharge device can always perform stable discharge, which contributes to the output of a good image.

[Brief description of the drawings]

FIG. 1 is a perspective view of a corona discharge device according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the corona discharge device according to the first embodiment of the present invention attached to a main body.

FIG. 3 is a sectional view of the corona discharge device according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a corona discharge device according to a second embodiment of the present invention.

FIG. 5 is a mounting portion of a corona discharge device according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a corona discharge device according to a third embodiment of the present invention.

FIG. 7 is a mounting portion of a corona discharge device according to a third embodiment of the present invention.

FIG. 8 is a lateral cross-sectional view of a corona discharge device according to a third embodiment of the present invention.

FIG. 9 is an enlarged view of the moving mechanism of the protruding electrode of the corona discharge device according to the third embodiment of the present invention.

FIG. 10 is a perspective view of a corona discharge device according to a fourth embodiment of the present invention.

FIG. 11 is a schematic diagram showing a state where the corona discharge device according to the fourth embodiment of the present invention is attached to the main body.

FIG. 12 is a schematic diagram of a moving mechanism of a protruding electrode of a corona discharge device according to a fourth embodiment of the present invention.

FIG. 13 is a schematic diagram of a moving mechanism of a protruding electrode of a corona discharge device according to a fifth embodiment of the present invention.

FIG. 14 is an enlarged view showing various protruding electrodes.

FIG. 15 is a schematic diagram of an analog copying machine to which the corona discharge device of the present invention is attached.

FIG. 16 is a schematic diagram of clamshell opening of an analog copying machine to which the corona discharge device of the present invention is attached.

[Explanation of symbols]

 2, 12, 22, 32, 42: Protruding electrodes 3, 13, 23, 33, 43: Support member 3c: Slope portion 13b, 23a: Protrusion 33b: Lever 47c: Protrusion portion 6, 16, 26, 36, 46 : Installation guide 100: Analog copying machine main body M1, M2, M3, M4, M5: Moving mechanism

Claims (4)

[Claims] 1. A corona discharge device having a projecting electrode and supported inside an image forming apparatus, comprising: a protection member for protecting the electrode tip portion of the projecting electrode so that the electrode tip portion is not exposed. A supporting member that supports the protruding electrode, an engaging portion that is provided on the supporting member and that engages with a mounting member that is provided on the image forming apparatus side, and an engagement between the engaging portion and the mounting member. And a moving mechanism that moves the support member to a position where the electrode tip of the protruding electrode is protected by the protection member when the corona discharge device is removed. 2. The corona discharge device according to claim 1, wherein the engagement between the engaging portion and the mounting member is disengaged when the electrode tip of the protruding electrode is separated from the surface to be discharged. . 3. The corona discharge device according to claim 1, wherein the engagement between the engagement portion and the mounting member is released when the corona discharge device itself is detached from the image forming apparatus main body. 4. The corona discharge device according to claim 1, wherein the engagement between the engagement portion and the mounting member is released when the inside of the image forming apparatus is opened.