JPS63237080A - Corona discharger - Google Patents

Abstract

PURPOSE:To permit easy mounting and dismounting of a corona discharger without damaging its corona discharge part which is formed by covering a dielectric-coated electrode disposed on the end face of a supporting base plate with a network electrode by sandwiching said discharge part by two sheets of side plates so that only the corona discharge part is exposed. CONSTITUTION:The corona discharge part consisting of the dielectric-coated electrode 12 of the corona discharger 1 and the network electrode 13 provided to cover said electrode is so constituted that said part does not come into contact with a guide hole 26 of a guide holding member 2 and that said part is guided by bringing the top end faces of both side plates 36, 37 thereof into contact with the guide hole 26 at the time of mounting the corona discharger 1 to a prescribed position by means of the guide holding member 2. In addition, the side faces of the side plates 36, 37 are guided by the member 2 while the front face of the top end is kept slid with the surface of an image carrier. The contact of the discharge part with the other parts is thereby entirely obviated and, therefore, said part is easily guided to and held at the prescribed position without being damaged at all.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a corona discharge device used in an electrostatic image forming apparatus.

[Conventional technology]

An electrostatic image forming device forms an electrostatic latent image on an image carrier,
An image is obtained by developing the latent image with toner, and in such an image forming apparatus, for example, the charge pattern is removed by charging the image carrier or neutralizing the charge on the image carrier. Corona discharge devices are used for various purposes, such as for

Conventionally, as such a corona discharge device, for example, US Pat. A structure with a wire mesh is shown in the figure.

Further, US Pat. No. 4,514,781 describes a corona discharger in which a dielectric-covered corona electrode is arranged in the longitudinal direction of a cylindrical base material, and a metal wire is spirally wound around the cylindrical base material. A corona discharge device is disclosed that is configured to be removably housed within a guide tube.

These corona discharge devices in which a counter electrode is arranged in contact with the dielectric covered electrode can form an extremely high potential gradient by applying an alternating current voltage to the dielectric covered electrode, so the peak-to-peak voltage V PP is 2000. It has the advantage that corona discharge can be started at a low potential around V, and corona generation efficiency is good.

[Problem that the invention seeks to solve]

Incidentally, in this type of corona discharge device, the distance between the corona discharger and the image bearing member, which is the member to be charged, is narrow and uniform to about 0.1 to 0.5 fl in order to improve the charging or neutralizing effect. It is necessary to maintain the
Furthermore, it is required to be arranged in a removable manner for inspection, replacement, etc. The first conventional example has an excellent corona discharge effect because the conducting wire and wire mesh are placed close to each other with the dielectric interposed between them. There is no disclosure of any means for maintaining a uniform gap with the carrier and detachably holding it.

Further, in the second conventional example, when the corona discharger is attached to and detached from the cylindrical guide tube, the metal wire constituting the discharge section of the corona discharger is attached to the edge of the guide tube on the inlet side. Contact may cause problems such as cutting the metal wire or damaging the dielectric covered electrode.

The present invention was made to solve the above-mentioned problems in conventional corona discharge devices, and is a corona discharge device that allows the corona discharge device to be easily attached to and removed from a predetermined position without the discharge portion coming into contact with other members. The purpose is to provide

[Means and effects for solving the problems] In order to solve the above problems, the present invention provides a flat dielectric support substrate,
a linear dielectric-coated electrode disposed on a longitudinal end surface of the support substrate; and a mesh electrode disposed across both sides of the support substrate so as to cover the upper surface of the dielectric-coated electrode. , a corona discharger comprising two side plates arranged to sandwich the mesh electrodes on both sides of the support substrate together with the side surfaces of the support substrate, and supporting and guiding the both side plates of the corona discharger. and a guide and holding means for detachably holding the corona discharger, forming a corona discharge device.

With this configuration, the support substrate is sandwiched between the two side plates so that only the corona discharge portion formed by covering the tR dielectric covered electrode network electrode placed on the support substrate is exposed, and the two side plates Since the side plate of the corona discharger can be supported and guided by the guide holding means, the discharge part of the corona discharger does not come into contact with other members when the corona discharger is attached or detached. Therefore, the corona discharger can be easily attached to and removed from a predetermined position without damaging the discharge section.

〔Example〕

Examples will be described below. FIG. 1 is a partially sectional plan view showing an embodiment of the corona discharge device according to the present invention installed in an image forming apparatus. In the same figure,
1 is a corona discharger; 2 is a guide and hold member for the corona discharger 1; Hold it in place. Reference numeral 4 denotes a main body frame for supporting the image carrier 3, the guide and holding member 2 of the corona discharge device, and the like.

FIG. 28 is a plan view of the corona discharger 1, and FIG.
(C) is a sectional view taken along the line AA' and line BB'. The corona discharger 1 includes a support substrate 11,
A dielectric-covered electrode 12 disposed on the upper end surface in the longitudinal direction of the support substrate 11 and a wire-shaped electrode 13 disposed astride both sides of the support substrate 11 so as to cover the dielectric-covered electrode 12. , a power supply contact 14 connected to the dielectric coated electrode 12 , a ground contact 15 connected to the mesh electrode, and the tip and rear of the discharge section consisting of the dielectric coated electrode 12 and the wire electrode 13 . It consists of insulating and gap-forming tapes 16 and 17 placed on the ends, and two side plates 18a and 18b placed on both sides of the support substrate 11. Note that 19 is an operating handle.

Next, a more detailed configuration of this corona discharger 1 will be explained based on the manufacturing process diagram shown in FIGS. Resin laminates, glass fiber reinforced silicone resin laminates,
Alternatively, it is made of heat-resistant glass, and as shown in the third foreigner, it has an inclined part 11a at the lower end and a click step part 11b at the upper part of the rear end. A glass coating 12 is attached to the tungsten wire 12a on the upper end surface of the support substrate 11 having such a shape, excluding the step portion 11b in the longitudinal direction.
A dielectric-coated electrode 12 with a diameter of about 0.31 mm, which was formed by applying step b, is arranged, and then a mesh electrode 13 made of a #100 metal mesh made of stainless steel, tungsten, nickel, titanium, etc. with a diameter of 0.05 is placed. The dielectric covered electrode 12
, cover it except for a part of the tip,
Both sides thereof are attached to both sides of the support substrate 11 using double-sided tape or the like. This state is shown in FIG. 3 (Bl). The lower ends of both sides of the mesh electrode 13 are formed to have a width that does not reach the lower ends of both sides of the support substrate 11.

Next, as shown in FIG. 3 (C1), the dielectric covered electrode 1
Part of the dielectric coating 12b at the tip of the conductor 12a is peeled off.
An electrode plate 14a made of stainless steel foil or the like having a thickness of about 0.11 mm is wound around the tip of the support substrate 11 in contact with the exposed conductor 12a, and a power supply contact 14 is placed on the inclined portion 11a of the substrate. Form. In addition, at the rear end of the mesh electrode 13, a thickness Q of 1 m is also made of stainless steel foil or the like.
A ground contact 15 is formed by providing an electrode plate 15a having a length of about m in contact with the cough mesh electrode 13 and wrapping around the lower end surface of the support substrate 11.

Then, as shown in FIG. 3 (01), polyimide.

A heat-resistant and abrasion-resistant tape 16 made of polytetrafluoroethylene or the like is applied to the connection between the conductor 12a and the electrode plate 14a, excluding the power supply contact 14, the end of the mesh electrode 13 in the vicinity, and the tip of the support substrate 11. Similarly, the heat-resistant and abrasion-resistant tape 17 is placed on the other end of the wire-like electrode 13 near the ground electrode to cover the mesh-like electrode 13 except for the lower end of the support substrate. Arrange the windings as shown. The dimension of the abrasion-resistant tape 16.17 that protrudes from the mesh electrode 13, that is, the thickness of the tape 16.17, is determined by the size of the abrasion-resistant tape 16.17, which is the thickness of the tape 16. 3 and the mesh electrode 13 is set to be equal to the desired gap size. Therefore, the heat-resistant and abrasion-resistant tapes 16 and 17 function as insulation and gap-forming members.

Then Bakelite, thermosetting unsaturated polyester (
BMC), polyphenylene 1 sulfide (PPS)
) Made of resin, etc., and has a power supply contact 14 and a ground contact 1.
Two heat-resistant side plates (approximately 2 mm thick) 18a and 18b, which are approximately the same shape as the support substrate 11 except that the width is slightly narrower than the support substrate 11 in the area where 5 is arranged, are attached using heat-resistant double-sided tape or the like. As shown in FIG. 2~fcl, the mesh electrode 1°3. The support substrate 11 is sandwiched between both sides of the support substrate 11 on which the electrode plates 14a and 15a are arranged. As a result, the discharge section consisting of the dielectric covered electrode 12 and the mesh electrode 13 covering it is formed by the side plates 13a and 18b.
The power supply contact 14 and the ground contact 15 are configured to protrude further and to be exposed from the side plates 13a and 18b. At this time, on the inner surfaces of the two side plates 18a and 18b,
Mesh electrode 13, electrode plates 14a, 15a, tape 16.1
It is preferable to form a recess corresponding to the arrangement position 7 and mold it.

Next, the operating handle 19 is attached to the click step 11b, leaving the step 11b slightly, and the corona discharger l is attached.
complete.

Next, the structure of the guiding and holding member 2 for guiding and holding the corona discharger 1 configured as described above in a predetermined position will be explained. This guide holding member 2, as shown in the fourth country person,
Both side plates 18a of a corona discharger 1 are formed by forming metal plates such as galvanized steel plates into a U shape.

It consists of a guide 21 that guides the guide 18b, and a front holder 22 and a rear holder 23 made of synthetic resin and placed at both ends of the guide 21. The guide 21 includes a fourth
As shown in the cross-sectional view of Figure (Bl), a heater mounting spring 24 is fixed to the side face of the heater mounting spring 24, and a thermistor heater 25 for heating the vicinity of the corona discharge device is mounted by the spring 24. The guide 21 is pressed and held on the side surface of the guide 21. Therefore, the guide 21 is configured to also function as a holder for the heater 25.Furthermore, the front portions of both side plates of the guide 21 are pushed outward to open the guide piece 21a. is forming.

The front holder 22 is formed in a U-shape, and has a notch 26a formed on its front end surface so that the upper end protruding discharge part of the corona discharger 1 does not come into contact with the corona discharger 1.
A guide hole 26 for insertion is provided. Note that both side plates 18a, 1 of the corona discharger 1 of the insertion guide hole 26
The arrangement position of the upper end guide surface 26b that guides the upper end surface of 8b is such that the upper end guide surface 26b is in sliding contact with the upper end guide surface 26b and the both side plates 18a, 1
When the upper end surface of the corona discharger 8b is guided, the discharge portion of the corona discharger 1 is arranged in a direction away from the normal position relative to the image carrier 3. Also, the front holder 22
As shown in Fig. 1, one end of an earth spring 27 made of stainless steel is fixed to the bottom of the holder, and its free end protrudes from the bottom notch toward the corona discharger insertion part inside the holder. It is located. Then, by screwing the bottom protrusion 22a of the holder 22 to the bottom protrusion of the guide 21, the holder 22 is attached to the front end of the guide 21 so that the U-shaped openings of both correspond to each other. It's stuck in place.

Like the front holder 22, the rear holder 23 is made of synthetic resin and has a U-shaped cross section, and its rear end is closed and is configured to hold the tip of the corona discharger 1 in semi-contact. and the bottom protrusion 23 of the rear holder 23
A is screwed onto the bottom protrusion 21a of the guide 21, thereby being attached to the rear end of the guide 21 so as to communicate with the U-shaped opening of the guide 21. Further, one end of a power supply spring 28 made of a stainless steel spring or the like is fixed to the rear holder 23, and its free end is arranged so as to protrude toward the inside of the holder.

As shown in FIG. 1, the guide holding member 2 configured in this manner is attached to a main body frame 4 supporting an image carrier 3 such as a dielectric drum along the length direction of the image carrier 3. It is attached so that it faces the surface. The corona discharger 1 is attached to and detached from the guide holding member 2 attached in this manner by inserting and removing it from the front holder 22 side.

When installing, first hold the handle 19 and remove the corona discharger 1.
Insert the tip of the front holder 22 into the guide holding member 2 from the guide hole 26 of the front holder 22. Guide hole 2 of front holder 22
The corona discharger 1 inserted while being guided by the earthing spring 27 protrudingly located immediately behind the guide hole 26
The top surface of the tip of the corona discharger 1 is pressed upward against the surface of the image carrier 3 as shown in the fifth recess.

At this time, the upper end surface 26 of the guide hole 26 of the front holder 22
b is formed in a direction that moves the corona discharger 1 away from the normal separation position with respect to the image carrier 3 as described above, so the corona discharger 1 is in a slightly tilted state as shown in FIG. 5 (8). The sides of both side plates 18a and 18b are guides 21.
The lower end surface of the corona discharger 1 is pressed by the grounding spring 27, and the tape 16 portion on the upper surface of the tip thereof is inserted while sliding on the surface of the image carrier.

When the tip of the corona discharger 1 reaches the closed part of the rear holder 23, the power supply contact 14 contacts the power supply spring 28, and the spring force of the power supply spring 28 causes the tip of the corona discharger 1 to close to the image carrier 3. pressed against the surface.

Therefore, this power supply spring 28 functions not only as an electrical connection means but also as a means for pressing the image carrier 3 of the corona discharger 1. Also, at this time, the stepped portion 1 provided in the corona discharger 1
1b is fitted into the guide hole 26 of the front holder 22. As a result, the ground spring 27 comes into contact with the ground contact 15, and the ground spring 27 also presses the rear end of the corona discharger 1 against the image carrier 3 with the same pressure as the front end.
Furthermore, the stepped portion 11b engages with the guide hole 26, and the corona discharger 1 is in a locked state. In this state, the upper end surface of the stepped portion 11b and the upper end surface 26 of the guide hole 26 are
A slight gap is formed between the two.

This complete installation state is shown in FIG. 1 and FIG. 5(B).

When this corona discharger 1 is attached, the heat-resistant and wear-resistant tapes 16.17 provided at both ends of the upper part of the discharger 1 come into contact with the surface of the image carrier 3, and the image is removed by the thickness of the tape 16.17. A uniform gap is formed between the surface of the carrier 3 and the linear electrode 13 forming the discharge section.

Note that even if the image carrier 3 rotates during operation of the image forming apparatus in this state, the tapes 16 and 17 that are in contact with the image carrier 3
Since it is made of heat-resistant and abrasion-resistant synthetic resin, it hardly wears out and can maintain a constant gap for a long period of time. Therefore, the dielectric covered electrode 12 and the mesh electrode 1
When operating as an eraser by applying, for example, an alternating current voltage with a V P-P of about 2000 .mu. during the period of 3, the image carrier 3 can be uniformly and completely neutralized over a long period of time.

As described above, in this embodiment, when the corona discharger is installed in a predetermined position via the guide and holding member, the discharge portion consisting of the dielectric covered electrode of the corona discharger and the mesh electrode provided to cover it is does not contact the guide hole of the guide holding member, but guides the upper end surfaces of both side plates in contact with the guide hole, and slides the top surface of the tip part onto the surface of the image carrier while sliding the side surfaces of both side plates. Since the discharge part is guided by the guide holding member, the discharge part never comes into contact with other members, and therefore can be easily guided and held in a predetermined position without being damaged in any way.

In addition, the top surface of the corona discharger slides on the surface of the image carrier, and the image carrier is used as a part of the guide member when attaching and detaching the corona discharger. The guide member can be simplified without requiring any other guide means for regulating movement in the body direction. Therefore, when attaching and detaching the corona discharger, there is no need for a mechanism to separate the corona discharger from the image carrier, and the attaching and detaching operation is simplified and no extra space is required, making it compact and easy. With this configuration, a corona discharge device with good operability and high accuracy can be obtained.

Note that when the top surface of the tip of the corona discharger slides along the surface of the image carrier, a heat-resistant and wear-resistant synthetic resin tape is wound around the top surface of the tip of the corona discharger, so that the top surface of the tip of the corona discharger slides along the surface of the image carrier. If the drum is made of a material with high surface strength, such as a dielectric drum or an amorphous silicon photoreceptor drum, no damage will be caused to either of them.

Furthermore, the gap accuracy between the dielectric-coated electrode and the mesh electrode forming the discharge part of the corona discharger and the image carrier is determined by the straightness of the support base material.
A dielectric covered electrode 12 is provided along the longitudinal end surface of the support substrate 1, and a mesh electrode is arranged to cover it.
Since maintaining the straightness of No. 1 is much easier than with a cylindrical base material, the queen gap can be maintained with high precision. Also, the longitudinal end face of the support board is coated with dielectric material! In the case where the electrodes are arranged, there is also an advantage that even if the electrodes are curved within the end surface, the size of the gap is hardly affected.

In the above embodiment, the surface of the image carrier is used as part of the guide means when attaching and detaching the corona discharger. FIGS. 6(A) and 6(IB) are a partially omitted plan view and a cross-sectional view thereof showing a second embodiment of the present invention, and the same or equivalent parts as in the first embodiment are indicated by the same reference numerals. In this embodiment, when the corona discharger is attached or detached, the discharger does not come into contact with the image carrier, and a guide portion for the discharger in the vertical direction is also formed in the guide holding member.

That is, the main difference between the corona discharger 1 in this second embodiment and the first embodiment is that both side plates 18a and 18b
Two points are formed on the outer surface of the holder, protrusions 31 and 32 for support, near the tip and rear ends, respectively, and tapes 16 and 17 for insulation and gap formation are omitted. , and the rest are completely the same, with the only difference being the arrangement position of the power supply contact 14.

On the other hand, the guide and holding member 35 is made of heat-resistant synthetic resin or the like and has a U-shaped cross section, and the inner surfaces of its both sides 36 and 37 are provided with guides for supporting protrusions 31 and 32 of the corona discharger l. Guide grooves 38 and 39 are formed to reach from the insertion entrance side of the corona discharger 1 to a position corresponding to the tip protrusion 31 and 32 at a predetermined stop position of the corona discharger 1.

Further, the corona discharger 1 is inserted into the guide groove 38, 39 by fitting the protrusion 31, 32 of the corona discharger 1 into the guide holding member 35, and then positions the corona discharger 1 at a predetermined position relative to the image carrier 3. When the discharge part of the corona discharger 1 reaches a predetermined value, the gap regulating part 38a is set to a predetermined value.
, 39a are formed. These gap regulating portions 38a, 3
9a is constructed by notching the upper edges of the guides 138, 39 upward and forming the guide grooves 3B, 39 partially wide. In addition, the entrance portions of the guide grooves 38 and 39 are appropriately widened so that the protrusions 31 and 32 of the corona discharger 1 can be easily inserted therein.

Further, an earth spring 27 and a power supply spring 28 are attached to the front and rear parts of the bottom of the guide holding member 35, respectively.
Their free ends are arranged to protrude toward the interior of the guiding and holding member 35 through the bottom notch 35a.

After the guide holding member 35 configured as described above is attached to a predetermined position facing the image carrier 3 of the image forming apparatus, when attaching the corona discharger 1 to the guide holding member 35, hold the handle 29 and push the tip protrusion. 31.32 is the guide for the holding member 35? Insert the tip into the guide holding member 35 while fitting it into the guide and holding member 35. By this insertion operation, the corona discharger 1 has its protrusions 31 and 32 connected to the guide 13.
8. Insert toward the tip while being guided by 39. At this time, the lower end surface of the corona discharger 1 sequentially contacts the earth spring 27 and the power supply spring 28, and continues to be inserted while being pressed by them. When the tip ridge 31 of the corona discharger 1 reaches the end of the guide groove 38, 39, the insertion operation is stopped.

At this time, each protrusion 31.32 has reached the gap regulating portions 38a, 39a of the guide groove 38.39, and each contact point 14.15 for power supply and grounding is connected to the power supply spring 28.
, are in contact with the earth spring 27, and therefore, due to the pressing force of each of these springs 27, 28, in the corona discharger 1, each protrusion 31, 32 is in contact with the gap regulating portion 38a.

It is pressed toward the image carrier 3 so as to contact the upper edge of the discharge portion 39a, and the discharge portion is held with a predetermined gap relative to the image carrier 3. Further, when removing the corona discharger for inspection, replacement, etc., the corona discharger can be easily removed from the guide holding member 35 by grasping the handle 29 and pulling it out.

In this way, also in this second embodiment, the corona discharger can be attached and detached by guiding its side plates with the guide and holding members, and can be held at a predetermined position with respect to the image carrier, so that the discharge portion of the corona discharger is does not come into contact with other parts,
Therefore, the corona discharger can be easily attached and detached with an N-only configuration without causing any damage to the discharge section.

〔Effect of the invention〕

As described above based on the embodiments, according to the present invention, the corona discharge section formed by covering the dielectric covered electrode arranged on the end surface of the support substrate with the mesh electrode is sandwiched between the two side plates, and the corona discharge section is sandwiched between the two side plates. Since only the corona discharge part is exposed and the side plate is supported and guided by the guide member, the discharge part of the corona discharger does not come into contact with other parts when the corona discharger is attached or detached. There is less contact, and the corona discharger can be easily attached and detached with a simple configuration without damaging the discharge section.

[Brief explanation of drawings]

FIG. 1 is a partially sectional plan view showing the first embodiment of the corona discharge device of the present invention installed in an image forming apparatus, and FIG. 2 (8) shows the corona discharge device. Plan view,
Figure 2 CB+, (C1 is A of the corona discharger in Figure 2)
- Cross-sectional view along line A' and B-B', Figure 3 (8) -
■) is a diagram showing the process of creating a corona discharger, Figure 4^,
[B] is a perspective view of the guide holding member and a sectional view thereof taken along line c-c', and FIG. 5(c). ■) is a diagram showing the process of attaching the corona discharger to the guide holding member, and Figure 6^, o3) is a partially omitted plan view showing the second embodiment of the present invention and a diagram taken along line DD'. FIG. In the figure, l is a corona discharger, 2 is a guide holding member, and 3 is a corona discharger.
1 is an image carrier, 4 is a frame, 11 is a support substrate, 12 is a dielectric covered electrode, 13 is a wire-like electrode, 14 is a power supply contact, 1
5 is a ground contact, 16.17 is an insulation/gap forming tape, 18a, 18b are side plates, 19 is a handle, 21 is a guide,
22 is a front holder, 23 is a rear holder, 24 is a heater holding spring, 25 is a thermistor heater, 26 is a guide hole, 27 is a ground spring, 28 is a power supply spring, 29 is a handle, 31.32 is a protrusion, 35 is the guide holding member, 36°37
38 and 39 are side plates, 38 and 39 are guide grooves, and 33a and 39a are gap regulating portions. Patent applicant: Olympus Optical Industry Co., Ltd. Figure 3 11a old) (C)

Claims (1)

[Claims] A flat dielectric support substrate, a linear dielectric covered electrode disposed on the longitudinal end surface of the support substrate, and a linear dielectric covered electrode extending over both sides of the support substrate so as to cover the upper surface of the dielectric covered electrode. a corona discharger comprising a mesh electrode arranged in such a manner that the mesh electrode is disposed on both sides of the support substrate, and two side plates arranged so as to sandwich the mesh electrode on both sides of the support substrate together with the side surfaces of the support substrate;
A corona discharge device comprising guide and holding means for supporting and guiding the both side plates of the corona discharger and detachably holding the corona discharger.