JPH10186798A - Corona discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the using life of a serrated electrode plate in a corona discharger using a serrated electrode. SOLUTION: In a corona discharge device having casing members 12, 13, a corona discharge electrode 21 within their openings, and support blocks 1, 14 for holding the electrode 21 substantially in parallel to the members 12, 13, it has a double edge type thin plate type corona discharge electrode 1 having a first line of saw tooth-like projection 22a protruded in y-direction toward the outside of the openings and distributed in z-direction and a second line of serrated projection 22B protruded in the opposite direction to the above protruding direction, which are integrally continued. This device also has a discharge suppressing electrode 24 with smooth edges which is extended along the second line projection 22B so that the y-directional width is further extended from the base of the electrode 21 to the outside from the second line projection 22B. The suppressing electrode 24 has a dent 26 for receiving the second line projection 22B. This device also has an insulator 10 for enclosing the second line projection 22B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge device using a sawtooth electrode, and more particularly, but not exclusively, to a charge for forming an electrostatic latent image in an electrophotographic recording device. Charger for charging the carrier, transfer charger for transferring the visible image on the charge carrier to transfer paper
Charger for removing electricity from a jaw, charge carrier or transfer paper
The present invention relates to a corona discharge device used for a jaw or the like.

[0002]

2. Description of the Related Art For example, a discharge wire is used as a discharge electrode of a charging charger for charging a charge carrier for forming an electrostatic latent image. In some cases, a saw-tooth electrode is used instead. For example, Japanese Patent Application Laid-Open No.
A 0.1 mm thick stainless steel plate has band-saw-shaped, saw-toothed edges by etching, and the apex (point) of each tooth
Has a curvature of 40 μm or less to concentrate the discharge electric field at the apex. Due to this electric field concentration, the voltage to be applied to the electrodes in order to generate a desired corona discharge is low, so that a low-cost power supply circuit (high-voltage generation circuit) can be used.

[0003] However, as with the case of using discharge wires, they are contaminated with toner or dust and discharge products. Since the electric field (discharge) concentrates on the apex (point) of the saw tooth, the electric field (discharge) tends to be contaminated, and the discharge characteristics deteriorate due to the contamination. Corrosion (corrosion) due to corona discharge occurs at the tip, and the shape of the tip gradually changes, increasing the discharge voltage. When the stain becomes severe, the discharge efficiency of the stained portion is reduced or intensive local discharge is caused to cause uneven discharge, and various defects on the image, such as white stripes, black stripes, uneven recording density, decreased recording density, etc. Occurs. To prevent this, it is necessary to periodically clean the saw-tooth electrode.

[0004]

Problems to be Solved by the Invention
No. 1 discloses a mechanism for polishing the tip of a saw tooth with a cleaning member. However, because of the saw teeth, it is clear.
Is difficult and especially difficult to automate. Further, the cleaning member is worn out early. Corrosion due to corona discharge at the point is unavoidable, and even with effective cleaning, wear due to the corrosion is inevitable.

An object of the present invention is to extend the life of a saw-tooth electrode plate in a corona discharge device using a saw-tooth electrode.

[0006]

[Means for Solving the Problems]

(1) The present invention provides a casing member (12, 1) extending in the z direction.
3) a corona discharge electrode including a corona discharge electrode (21) in the opening of the casing member extending in the z direction and electrode support means (1, 14) for holding the electrode substantially parallel to the casing member. A first row of a plurality of saw-tooth projections (22A) projecting in the y-direction outward of the opening and distributed in the z-direction;
It is characterized by comprising a double-blade thin corona discharge electrode (21) integrally and continuously having a second row of a large number of serrated projections (22B) projecting in a direction opposite to the projecting direction and distributed in the z direction.

According to this, the first row of saw-tooth projections (22A)
When the discharge characteristics of the second row are deteriorated, the corona discharge electrode (21) is rotated by 180 degrees about the z-axis, and the second row of sawtooth projections (2
2B) at the position where the first row of serrations (22A) was located before, and also with good discharge characteristics, the corona discharge electrode (2A).
1) can be used, and the corona discharge electrode (21) has twice the life.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION

(2) It extends in the z-direction along the second row of saw-toothed projections (22B), and the width in the y-direction is set at
Extend further out than the serrations of the row,
It further includes a discharge suppressing electrode (24) having the same potential as the corona discharge electrode (21), the outer edge of which is smoother. According to this,
Since the discharge suppressing electrode (24) extends further beyond the end of the second row of sawtooth projections than the discharge suppressing electrode (24), a corona discharge is generated on the first row of sawtooth projections (22A). When a high voltage is applied to the discharge electrode (21), the discharge electric field is not concentrated on the second row of sawtooth projections (22B), and the unused sawtooth projections (22B) are less deteriorated. A discharge voltage is applied to the outer edge of the discharge suppressing electrode (24). However, since the edge of the discharge suppressing electrode (24) is smooth, the discharge electric field concentrates on the first row of sawtooth-shaped protrusions (22A) in use. Since current flows there, the discharge suppression electrode
(24) does not substantially generate discharge.

(3) The discharge suppressing electrode (24) has a depression (26) for receiving the second row of sawtooth projections (22B). According to this, the unused second row of saw-tooth projections (22B) fits into the depressions (26) of the discharge suppression electrode (24), whereby the discharge suppression electrode (24) is in the second row of sawtooth shape. The effect of shielding the projection (22B) is high, and the effect of (2) is even higher.

(4) An insulator (10) surrounding the second row of saw-tooth projections (22B) is provided. According to this, since the second row of the saw-tooth projections (22B) is insulated by the insulator (10), the corona discharge electrode (21) is generated to generate a corona discharge in the first row of the saw-tooth projections (22A). ), When a high voltage is applied, the second row of sawtooth-like projections (22B) does not discharge, and the unused sawtooth-like projections (22B) do not discharge.
Deterioration is small.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0012]

【Example】

-First Embodiment- FIG. 1A shows an exploded end of a power supply connection side of a first embodiment of the present invention. One end of a casing side plate 12 made of a metal plate is fixed to the power supply side end block half 1,
Moreover, one end of the insulating back plate 10 is fixed. One end of a casing side plate 13 made of a metal plate is fixed to another power supply side end block half 14. The end block half 1 has a low surface 4 for facilitating insertion of the sheet corona discharge electrode 21, on which metal pins 5 are erected, and the end block half 14 also has a sheet corona discharge electrode 2.
There is a lower surface 17 for receiving one end and a pin hole for receiving the tip of the metal pin 5.

The thin plate corona discharge electrode 21 is formed by etching a 0.1 mm stainless steel plate and forming a plurality of saw teeth 2 in a first row at a predetermined pitch on a side end extending in the z direction (longitudinal direction).
2A, a plurality of saw teeth 22B of the second row having the same pitch are formed on another side end opposite to and parallel to the side end. A round hole 23 through which the pin 5 passes is formed at an end of the electrode 21.

Grid connection pins 6 and electrode connection pins 7 are implanted in the power supply side end block half 1, are connected to the pins 6 in the half 1, extend into the slits 3, and are inserted into the slits 3. There is a metal lead plate (not shown) against which the claw 33 is pressed. The pin 7 is connected to the pin 5 by a connection conductor (not shown) in the half 1.

At the end on the other side in the z direction, there is also a front end block half (not shown) having the same structure as the power supply end block half 1, and the other end of the casing side plate 12. The part is fixed. However, the front end block half (not shown) has pins 6 and 7 for power supply connection.
There is no. At the end on the other side in the z direction, there is also a front end block half (not shown) having a structure similar to that of the power supply end block half 14, and the casing side plate 13
Is fixed at the other end.

The grid plate 30 is a metal plate having an opening 31 in which a metal mesh 32 is provided, and has nails 33 and 34 protruding in the x direction at the power supply end. The end block halves 1 and 14 have low surfaces 2 and 15 for receiving the claws 33 and 34 and slits 3 and 1 connected to this surface for receiving the claws 33 and 34.
There are six.

The insulating back plate 10 has a slit groove 11 extending in the z direction (FIG. 7B), which is continuous with the lower surface 4 for receiving and inserting the electrode 21 of the power supply side end block half 1.

The electrode 21 is engaged with the pin 5 such that the pin 5 of the power supply side end block half 1 passes through the round hole 23 of the thin plate corona discharge electrode 21 to insulate the longitudinal portion of the electrode 21 extending in the z direction. Insert into the slit groove 11 of the back plate 10 of the body,
The claws 33 of the grid plate 30 are inserted into the slits 3 of the half 1, and the claws 34 of the grid plate 30 are received in the slits 16 and the pins 14 of the half 1 are received.
Is applied to the half 1, the screws are passed through the screw holes 18, 19 of the half 14, and the screws are screwed into the screw holes of the half 1, so that the half 1 supporting the side plate 12, the electrode 21, and the grid plate The half 14 supporting the side plate 13 and the side plate 13 are integrated. Similarly, on the other side in the z direction, the front end block halves (two pieces) are
The electrode 21 and the grid plate 30 are fixed integrally. Thus, the corona discharger is completed. In this finished product, the tips of the sawtooth 22 </ b> A in the first row of the electrodes 21 face the mesh 32 of the grit plate 30.

FIG. 1 (b) shows a cross section of the finished product [(a)
Cross section as viewed in the direction of the line 1B-1B). Since the first row of saw teeth 22 </ b> A is exposed in the space between the back plate 10 and the grid plate 30, the corona discharge is caused between the charged object (or the charged object) on the other side of the grid plate 30 and the electrode 21. By applying a voltage to the side plates 12 and 13 to apply a voltage for adjusting the electric field distribution having the same polarity as the electrode 21 and applying a voltage to the grid plate 30 to control the amount of charge (or the amount of charge removal), the first row of sawtooth teeth 22
A corona discharge occurs at the tip of A. At this time, the saw teeth 22B in the second row are far from the charged object, and furthermore, the back plate 10 made of the insulator.
, The discharge is very small, and the discharge current almost flows to the tip of the sawtooth 22A in the first row.

When the first row of saw teeth 22A is not suitable for suitable charging (or static elimination), cleaning is performed. However, when the first row of saw teeth 22A cannot be used for suitable charging at an early stage, cleaning is performed.
Alternatively, before that, the process shown in FIG.
(A), the electrode 21 is removed from the end block, and the electrode 21 is turned around by 180 degrees around the z-axis and turned upside down, and re-attached to the end block in the same manner as in the above-described assembling process. Thereby, the saw teeth 22 </ b> B in the second row face the mesh 32 of the grid plate 30. At this time, since the second row of saw teeth 22B has not been substantially consumed, the charged object (or the charged object) located on the other side of the grid plate 30 is attained.
A corona discharge voltage is applied between the side plate 12 and the electrode 21.
By applying a voltage for adjusting the electric field distribution having the same polarity as that of the electrode 21 to the electrode 13 and a voltage for controlling the amount of charge (or the amount of charge removal) to the grid plate 30, a good corona discharge is applied to the tip of the sawtooth 22B in the second row. Is generated.

This allows the electrodes 21 to be used for substantially twice as long as a row of saw teeth.

Second Embodiment FIG. 2 shows a second embodiment of the present invention. In the case of the first embodiment shown in FIG. 1, as the discharge voltage rises as the saw teeth 22A in the first row become dirty or worn, the slit grooves 1
1 because the second row of saw teeth 22B in
The minute discharge of the row of saw teeth 22B is enlarged, and the first row of saw teeth 22
If the use in a state where the discharge failure occurs in A becomes long, the saw teeth 22B in the second row also wear out. In the second embodiment, in order to suppress such wear, a conductor plate (metal plate) 24 for suppressing electric field concentration on the tip of the sawtooth 22B in the second row is provided. Note that FIG. 2 corresponds to FIG. 1, and a description of members common to the first embodiment in the second embodiment will be omitted. The conductor plate 24 is, like the first embodiment,
When fixing the electrode 21 to the end block,
And is fixed to the end block.

In this state, the conductor plate 24 is fixed.
The upper edge extending in the z-direction (upper: y-direction) is lower than the tip of the sawtooth 22A in the first row (farther than the mesh 32 of the grid plate 30), but the lower edge is more than the sawtooth 22B in the second row. It is below (in the opposite direction to y), and has penetrated deeply into the slit groove 11 of the back plate 10. Since the conductive plate 24 is in contact with the electrode 21 and its lower edge (same for the upper edge) is a smooth straight line that is less likely to cause electric field concentration, the electric field concentration at the tip of the sawtooth 22B in the second row And the wear of the tips of the second row of saw teeth 22B during use of the first row of saw teeth 22A is reduced.

In the first modification of the second embodiment, two conductor plates 24 are provided, and an electrode is interposed between them. This further reduces the electric field concentration on the tip of the second row of saw teeth 22B.

In the second modification, the conductor plate 24 has a cross section of U
The mold is folded in two, and the electrode 21 is inserted into the central slit groove. This completes the suppression of electric field concentration on the tip of the second row of saw teeth 22B.

Third Embodiment FIG. 3 shows a third embodiment of the present invention. In the third embodiment, the conductor plate 24 has a valley-shaped depression 26 that receives the sawtooth 22 </ b> B of the second row of the electrodes 21. Similarly to the second embodiment, when the electrode 21 is fixed to the end block, the electrode 21 is fixed to the end block while being superimposed on the electrode 21. At this time, the electrodes 21 of the conductor plate 24 are so set that the sawtooth 22B of the second row fits into the recess 26 of the conductor plate 24.
The area 27 corresponding to the end face of the second row of saw teeth 2 is reduced by polishing, and the area of the second row of saw teeth 2 is reduced by the shaving thickness (x direction) on this face.
2B fits into the recess 26 in the x direction, and the second row of saw teeth 22B is within the thickness region (x direction) of the conductor plate 24.
FIG. 3 shows an embodiment corresponding to FIGS. 1 and 2,
Description of members common to the first and second embodiments in the third embodiment will be omitted.

In the third embodiment, since the conductive plate 24 covers the lower side of the tip of the second row of saw teeth 22B, the second row of saw teeth 22B
B has a high effect of suppressing the electric field concentration in the direction in which the electric field gradient becomes the strongest (y direction), and the tip of the second row of saw teeth 22B is less consumed during use of the first row of saw teeth 22A.

[Brief description of the drawings]

FIG. 1A is an exploded perspective view of a power connection side end according to a first embodiment of the present invention, and FIG. 1B is an assembled 1B shown in FIG.
FIG. 1B is a sectional view taken along line -1B.

FIG. 2 (a) is an exploded perspective view of an end portion on a power supply connection side according to a second embodiment of the present invention, and FIG. 2 (b) is an assembled 2B shown in FIG.
FIG. 2B is a sectional view taken along line 2B.

FIG. 3A is an exploded perspective view of a power connection side end according to a third embodiment of the present invention, and FIG. 3B is an assembled 3B shown in FIG.
FIG. 3B is an enlarged sectional view taken along line -3B.

[Explanation of symbols]

1: half of the end block 2: lower surface for receiving the claw 33 3: slit for receiving the claw 33 4: lower surface for receiving the electrode 21 insertion 5: pin 6: grid connection pin 7: electrode connection pin 8, 9: screw hole 10: back plate 11: Slit groove 12, 13: Casing side plate 14: End block half body 15: Claw 34 receiving low surface 16: Claw 34 receiving slit 17: Electrode 21 insertion receiving low surface 18, 19: Screw through hole 21: Thin plate corona Discharge electrode 22A: First row serrated projection 22B: Second row serrated projection 23: Pin 5 passing hole 24: Discharge suppressing electrode 25: Pin 5 passing hole 26: Valley-shaped dent 27: Electrode 21 end surface contact area 30: Grit plate 31: Opening 32: Metal mesh 33, 34: Grit plate 30 nails

Claims (4)

[Claims] 1. A casing member extending in the z direction, a corona discharge electrode extending in the z direction within an opening of the casing member, and an electrode supporting means for holding the electrode substantially parallel to the casing member. A plurality of sawtooth-shaped projections protruding in the y-direction toward the outside of the opening and distributed in the z-direction, and a second row of protruding directions opposite to the protruding direction and distributed in the z-direction. A corona discharge device comprising a double-blade thin-plate corona discharge electrode having a large number of saw-tooth protrusions integrally and continuously. 2. A protruding end extending in the z-direction along the second row of sawtooth projections, and having a width in the y-direction extending further from the backbone of the corona discharge electrode than the second row of serrations. The corona discharge device according to claim 1, further comprising a discharge suppression electrode having a smoother edge and the same potential as the corona discharge electrode. 3. The corona discharge device according to claim 2, wherein the discharge suppressing electrode has a recess for receiving the second row of serrated protrusions. 4. The corona discharge device according to claim 1, further comprising an insulator surrounding the second row of sawtooth-shaped projections.