JP3429860B2 - Corona discharge device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge device for uniformly charging an object to be charged by utilizing a corona discharge phenomenon.
In particular, the present invention relates to a corona discharge device capable of miniaturizing a discharge device, stabilizing a discharge current, and lowering a driving voltage. 2. Description of the Related Art A corona discharge device using a pin-shaped or saw-tooth-shaped discharge electrode as disclosed in, for example, JP-A-60-80870 has been proposed. FIG. 17 (a) shows the configuration of this type of corona discharge device.
Shown in This device has a grid electrode 11, a shield case 12 having a U-shaped cross section, an insulating substrate 14 supported by the shield case 12, and a stainless steel (0.1 mm thick) provided on the insulating substrate 14. ) Sawtooth discharge electrode portion 15). [0003] The shield case 12 is provided for the purpose of preventing the discharge from reaching other parts in the apparatus, stabilizing the discharge, and reducing the drive voltage. Although the discharge can be stabilized to some extent only by the shield case 12,
In order to obtain further sufficient charging uniformity, a grid electrode is located at the opening of the shield case. A voltage slightly higher than the charging potential of the photoconductor is applied to the grid electrode 11, and where the discharge amount is larger than the desired charging potential, the larger amount is absorbed by the grid electrode 11, so that the charging potential is reduced. Uniformity can be achieved. FIG. 1B is a front view of the sawtooth discharge electrode portion 15. When the pitch p between each discharge electrode tooth is 2 mm, the tip of the saw-tooth discharge electrode 15 is
4 mm from the edge of photoconductor 4 to the photoconductor 4 side
It is provided on the insulating substrate 14 so as to be in a protruding position. The sawtooth discharge electrode 15 is connected to the high voltage power supply 9. By applying a high voltage (for example, -4.5 kV) to the sawtooth discharge electrode 15 by the high-voltage power supply 9, corona discharge is stably generated from the tooth tip, and the surface of the photoconductor 4 is charged. A grid electrode 11 to which a voltage (for example, -620 V) smaller than a voltage applied to the sawtooth discharge electrode 9 is applied by a high-voltage power supply 10 is provided between the discharge electrode 15 and the photoconductor 4. . The grid electrode 11 controls the charging potential of the photoconductor 4 to be a predetermined potential. FIG. 18 is a model diagram (a) of the conventional corona discharge device using the sawtooth discharge electrodes shown in FIG. 17, a graph (b) showing its discharge characteristics, and FIG. The equivalent circuit diagram (c) is shown. A high-voltage power supply 21 is connected between a discharge electrode 17 corresponding to the sawtooth discharge electrode 15 and a discharge object 20 corresponding to the photoconductor 4 in FIG. Corona discharge is generated in the gap g between them. The driving voltage is a certain voltage (discharge starting voltage V
th), corona discharge starts, and the drive voltage E and the discharge current I after the start of the discharge have a substantially linear relationship if limited to the actual use range (discharge current of 0.4 A or more per pin of discharge current). Can be considered to have. Therefore, the discharge current I is represented by I = (E−Vth) / Rg (Rg: gap impedance corresponding to the gap) from FIG. The discharge starting voltage Vth is substantially constant between the discharge electrodes, but the gap impedance Rg is about ± 30 between the discharge electrodes 15 due to the variation in the shape of the electrode tip and the influence of the deposits on the tip. % Variation. When the gap impedance varies between each discharge electrode 15 by ± 30%,
The discharge current also fluctuated at a rate of ± 30%, causing uneven charging. Further, in the conventional corona discharge device, a shield case is provided so as to cover the discharge electrode, and a grid electrode is provided on the opening surface of the shield case. Because a gap of 5 to 10 mm is provided between the discharge electrode and the photoconductor, the shield case, and the grid electrode to ensure leak resistance and safety for the photoconductor, the shield case, and the grid electrode. In addition, in order to increase the size of the apparatus and charge the photoreceptor to a predetermined voltage, it is necessary to increase the drive voltage of the discharge electrode to discharge more than necessary to the grid electrode and the shield case. Further, as described above, since the discharge amount of the discharge electrode is increased, there is a problem that the discharge stability, the charging efficiency and the charging uniformity are poor, and the amount of ozone generated due to the discharge amount is also large. The present invention has been made in view of the above problems, and provides a corona discharge device which has a smaller discharge amount, a smaller voltage applied to a discharge electrode, and is superior in discharge stability, charging efficiency, and charging uniformity as compared with the related art. Aim. The corona discharge device according to the present invention comprises a plurality of sawtooth-shaped discharge electrodes provided in the axial direction of a photoconductor for discharging the photoconductor on both sides of an insulating substrate. And the first
2 of the first and second discharge electrodes.
The pole train is connected via a resistor having a predetermined resistance value.
A corona discharge device connected to the voltage power, the
A voltage having an oscillating waveform is imprinted on the first and second discharge electrode arrays.
And one of the first and second discharge electrode rows is
To fulfill the function as a pole, for each discharge electrode row,
It is characterized in that voltages are applied out of phase with each other. It should be noted that the phase shift is 180 °.
Most preferred. In this configuration, the discharge electrode pitch p of the first discharge electrode row and the discharge electrode pitch p of the second discharge electrode row are defined by the discharge electrodes. By disposing them at a half pitch p, the discharge electrode pitch becomes apparently small and becomes p / 2, so that the distance between the discharge electrode and the discharge target can be reduced,
Further, the driving voltage can be reduced, and the charging uniformity can be improved. In the corona discharge device of the present invention, the voltage waveform applied to the first and second discharge electrode rows is an oscillating waveform, and the phase of the voltage waveform applied to the first discharge electrode row and the second Since the phase of the voltage waveform applied to the discharge electrode row is shifted by, for example, 180 °, if the oscillation waveform of the applied voltage is a rectangular wave of 0 V (ground state) and the drive voltage that causes discharge, the first discharge electrode row When the driving voltage is applied to the second discharge electrode row, the second discharge electrode row is at 0 V (ground state) and acts as an auxiliary electrode of the first discharge electrode row. Conversely, the second discharge electrode row is in the discharge state. Sometimes, the first discharge electrode row acts as an auxiliary electrode, so that the discharge from each discharge electrode is stabilized, so that the grid electrode and the shield case become unnecessary,
The apparatus can be downsized, high charging efficiency can be obtained, and the amount of generated ozone can be reduced. An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of the corona discharge device of the present application, and FIG.
(A) is a perspective view of a discharge / auxiliary electrode part in the corona discharge device of the present application, (b) is a front view of a discharge electrode part, FIG. 3 is a cross-sectional view (a) of a part X in FIG. 2 (b), And (b) is a cross-sectional view at the Y portion. A common electrode 13a is formed on the insulating substrate 1a, and a plurality of (in this embodiment, 107) discharge electrodes 2a are formed on the insulating substrate 1a at a predetermined interval d from the common electrode 13a. Part is provided. The discharge electrode 2a is made of stainless steel having a thickness of 0.1 mm, and is formed in a sawtooth shape by etching. The common electrode 13a and each discharge electrode 2a are about 50
It is electrically connected by a plurality of stabilizing resistors 16a (hereinafter referred to as chip resistors) having a resistance value of 0 MΩ. The number of the discharge electrodes 2a is 107, the pitch P between the respective discharge electrodes 2a is 2 mm, and the tip of the discharge electrode 2a is located at a position protruding 2 mm from the edge of the insulating substrate 1a toward the photoconductor 4 side. Is bonded to the insulating substrate 1a. The distance g (hereinafter referred to as a discharge gap g) from the tip of the discharge electrode 2a to the surface of the photosensitive drum 4 is 3 mm. The first auxiliary electrode 18a is made of stainless steel having a thickness of 0.5 mm, and is attached to the insulating substrate 1a via the spacer 3a. A second auxiliary electrode 19a having the same shape and the same material as the first auxiliary electrode 18a is adhered to the back surface of the insulating substrate 1a. The common electrode 13a is connected to the voltage power supply 6 , and when the driving voltage (about -2.0 kV in this embodiment) is applied to the discharge electrode 2a by the voltage power supply 6 , the photosensitive member 4 and the auxiliary electrodes 18a and 19a are applied. Is discharged. The auxiliary electrodes 18a and 19a are connected to the voltage power supply 5, and the auxiliary electrodes 18a and 1a are connected by the voltage power supply 5.
By applying a voltage (approximately -500 V in this embodiment) smaller than the magnitude of the voltage applied to the discharge electrode 2a to 9a, the discharge current in the direction of the auxiliary electrode is reduced, and the charging efficiency is improved. The magnitude of the voltage applied to the auxiliary electrodes 18a and 19a may be smaller than the magnitude of the voltage applied to the discharge electrode 2a. The effect on the charging characteristics of the auxiliary electrode was confirmed by simulation and experiment. FIG. 4 is a model showing this corona discharge device as an equivalent electric circuit. Here, Vg is a discharge starting voltage for the photoconductor,
Vs is a discharge starting voltage for the auxiliary electrode, Rg is a gap impedance between the discharge electrode 2a and the photoconductor, Rs is a gap impedance between the discharge electrode 2a and the auxiliary electrodes 18a and 19a, Rc is a stabilizing resistor, and Ic is a value from the discharge electrode 2a. Total discharge current discharged (hereinafter referred to as total current),
Ig is a discharge current in the direction of the photosensitive drum (hereinafter referred to as a charging current) of the total current, Is is a discharge current of the total current in the direction of the auxiliary electrode (hereinafter referred to as an auxiliary current), and E is a drive voltage. . From this model, the charging current Ig is expressed by the equation (1). ## EQU1 ## The simulation conditions were set as follows. (1) The gap impedance Rg by each discharge electrode 2a,
And the variation rate of Rs is constant regardless of the discharge gap g. (2) Air gap impedance Rg and R at each discharge electrode 2a
The rate of change of s is equal. (3) The discharge start voltages Vg and Vs are constant between the discharge electrodes 2a. (4) The discharge starting voltages Vg and Vs are equal. (Charging current Ig variation) − (Void impedance Rg variation) between the case where the auxiliary electrode is provided on the side surface of the discharge electrode and the case where it is not provided based on the above simulation conditions
FIG. 5 shows the characteristics of. The variation in the charging current Ig is 107
When the maximum value of each of the charging currents Ig discharged from the discharge electrodes 2a is Igmax, the minimum value is Igmin, and the average value is Igave, Igpp (%) = | Igmax−Igmin | / Iga
This is a variation represented by ve. As shown in FIG. 5, the variation in the charging current Ig between the discharge electrodes 2a is smaller when the auxiliary electrode is provided on the side surface of the discharge electrode than when the auxiliary electrode is not provided.
It was confirmed that the charging current could be made uniform by a and 19a. FIG. 6 shows an experimental result of examining the charging characteristics when the auxiliary electrode is provided on the side surface of the discharge electrode and when the auxiliary electrode is not provided. The evaluation of the charging characteristics was performed by measuring the charging potential in the axial direction with respect to the photoreceptor drum, and measuring the magnitude of the charging ripple in the axial direction (hereinafter referred to as charging variation). According to the measurement results shown in FIG.
By providing a and 19a, it was confirmed that the driving voltage was reduced and the charging uniformity was improved, that is, the charging variation was reduced. Next, the auxiliary electrodes 18a and 19a and the discharge electrode 2
The effect of the distance between a was examined by simulation and experiment as described above. FIG. 7 shows the auxiliary electrode 18.
FIG. 9 is a simulation result of the relationship between the distance between the discharge electrodes 2a and 19a and the discharge electrode 2a and the variation in the charging current Ig.
As the distance between the discharge electrodes 8a and 19a and the discharge electrode 2a became smaller, the variation in the charging current Ig became smaller. FIG. 8 shows the results of an experiment on the relationship between the distance between the auxiliary electrodes 18a and 19a and the discharge electrode 2a and the charging characteristics. Similarly to the simulation result, it can be seen that as the distance from the discharge electrode 2a becomes smaller, the charging uniformity is improved (charge variation is reduced) and the driving voltage is reduced. In the conventional corona discharge device, the distance d (mm) between the discharge electrode 2a and a discharge object such as a grid electrode or a shield case is determined by the voltage applied to the discharge electrode 2a.
(KV), and assuming that the applied voltage of the discharge target is Vs (kV), d> | E−Vs | is usually set in order to prevent the discharge from the discharge electrode 2a from shifting to spark discharge or arc discharge. It is. However, in the present invention, since the high-resistance (500 MΩ) chip resistor 16a is provided between each discharge electrode and the voltage power supply, there is no danger of transition to spark discharge even if d ≦ | E−Vs |. Therefore, in the present invention, the distance between the discharge part of the discharge electrode and the auxiliary electrode can be set smaller, the corona discharge is stably maintained, the charging uniformity is improved, the driving voltage is reduced, and the apparatus is further improved. The size and thickness can be reduced. According to the above result, in this embodiment, the spacer 3
a and the thickness of the insulating substrate 1a are 1.5 mm, and the distance between each auxiliary electrode 18a, 19a and the discharge electrode 2a is 1.
5 mm. Next, the relationship between the discharge gap g and the charging current variation was examined by simulation and experiment. The graph shown in FIG. 9 is a result of the simulation. As can be seen from the simulation, it was confirmed that the smaller the discharge gap g, the smaller the variation in the charging current Ig. FIG. 10 shows an experimental result obtained by examining the relationship between the discharge gap g and the charging characteristics. As can be seen from the graph shown in FIG. 10, the smaller the discharge gap g, the lower the driving voltage and the smaller the charging variation, but the smaller the discharge gap g, the smaller the charging variation. This is because when the discharge gap g becomes smaller than the discharge electrode 2a pitch p (2 mm), the component (charge discharge variation) caused by the discharge electrode 2a pitch p in the charging variation.
This is because when the a-pitch p is 2 mm, a charging ripple having a cycle of 2 mm and 4 mm, a charging ripple of a cycle of 4 mm appears, and as the discharge gap g becomes smaller, the charging variation component caused by the pitch p of the discharge electrodes 2 a becomes larger. FIG. 11 shows the result of theoretically analyzing the influence of the pitch p of the discharge electrodes 2a on the charging characteristics by using an image method. The result of the theoretical analysis shows that the discharge electrode 2a
As a result, the result was obtained that when the pitch / discharge gap was larger than 1, in other words, when the discharge gap g was smaller than the electrode pitch p, the charge variation increased. From these results, in this embodiment, the discharge electrode 2
The pitch was set to 3 mm, which was slightly larger than the pitch a. As a result, it is possible to suppress the influence of the charge variation due to the pitch p of the discharge electrodes 2a, improve the charge uniformity, and further reduce the size of the device. A method of controlling the voltage applied to the discharge electrode 2a and the auxiliary electrodes 18a and 19a in this embodiment will be described. As can be seen from the applied voltage-discharge current characteristics shown in FIG.
H: high temperature and high humidity, NN: normal temperature and normal humidity, LL: low temperature and low humidity), the discharge amount is affected, and thus the charging potential varies. Therefore, if the auxiliary electrodes 18a, 19a and the discharge electrode 2a are controlled with a constant current, and the charging current Ig in the direction of the drum is constantly controlled, the environment is not affected. Therefore, the discharge becomes unstable. Next, the relationship between the control method of the voltage applied to the discharge electrode and the auxiliary electrode and the charging characteristics was examined by experiments in the following four cases. (1) Discharge electrode-constant voltage control, auxiliary electrode-constant voltage control (2) Discharge electrode-constant current control, auxiliary electrode-constant voltage control (3) Discharge electrode-constant voltage control, auxiliary electrode-constant current control (4 ) Discharge electrode-constant current control, auxiliary electrode-constant current control FIG. 12 (b) shows the experimental results. According to the experimental results,
The method (1) is the most excellent in charging uniformity, but has large fluctuations in charging potential due to environmental changes. In the control method of the above (4), on the contrary, the control of the charging current becomes unstable, so that the charging uniformity is poor. Therefore, since the charging current can always be controlled to be constant, the stability of the charging potential with respect to the environment is excellent.
In terms of good charge uniformity, as in the method (2) or (3), the discharge is stabilized by constant voltage control with respect to either the discharge electrode or the auxiliary electrode. It was found that constant current control should be performed on the other electrode to keep the charging current constant. In this embodiment, the charging current Ig required to charge the photosensitive member 5 to a predetermined potential (-600 V) is 20 A. Therefore, when using the method (2), first, the auxiliary electrodes 18a and 19a are applied with a predetermined voltage (about-
500V) and the auxiliary current Is is monitored, and the discharge electrode 2a is controlled such that the charging current Ig is always 20 A, that is, the total current It is | It-Is | = 20. May be controlled by constant current. When the control method (3) is used, first, the discharge electrode 2a is set to a predetermined voltage (about -2.0 k
V) and the total current It is monitored, and the auxiliary electrodes 18a, 18a, 1a and 1a are controlled so that the charging current Ig always becomes 20 A, that is, the auxiliary current Is satisfies the expression (2).
What is necessary is just to perform constant current control of the voltage to 9a. Further, the discharge electrode-constant voltage control, auxiliary electrode-
The method of constant voltage control is the most excellent in charging uniformity, but the charging current fluctuates due to environmental changes, so that the charging potential fluctuates greatly due to the environment. Therefore, while taking advantage of the excellent charging uniformity in this method, in order to improve the environmental characteristics, during rotation before the actual charging of the photoreceptor,
Constant current control of the discharge electrode 2a and the auxiliary electrodes 18a and 19a so that the discharge current to the photoreceptor is constant;
Hold or store the voltage value generated at that time,
There is a method (5) of controlling the auxiliary electrodes 18a and 19a and the discharge electrode 2a by the voltage value held or stored at the time of actual charging. As one embodiment of this method, the discharge electrode 2a and the auxiliary electrodes 18a and 19a are controlled at a constant current so that the total current It becomes 60 A and the auxiliary current Is becomes 40 A during the pre-rotation (the charging current at this time). Ig is Ig = 60
-40 = 20A). The voltage (for example, -2.1 kV) applied to the discharge electrode 2a generated at this time and the auxiliary electrode 18
a, 19a is held or stored, and the discharge electrode 2a is set to -2.
The constant voltage is controlled at 1 kV and the auxiliary electrodes 18a and 19a at -550V. FIG. 9B shows the result of measuring the charging characteristics in the same manner as described above by this method. As shown in the figure,
It was confirmed that the control method improved the controllability of the charging potential with respect to the environment. (Embodiment 2) FIG. 13 is a schematic diagram showing the configuration of an embodiment of a corona discharge device according to claim 2 of the present invention.
FIG. 14 is a perspective view of the electrode part (a) and a front view of the electrode part (b). The common electrode 13 is provided on the surface of the insulating substrate 1b.
b is formed on the surface of the insulating substrate 1b at a predetermined interval d from the common electrode 13b.
(Hereinafter, referred to as a first discharge electrode row). The discharge electrode 2b is made of stainless steel having a thickness of about 0.1 mm, and is formed in a sawtooth shape by etching. The common electrode 13b and each discharge electrode 2b are about 500
They are electrically connected by a plurality of chip resistors 16b having a resistance value of MΩ. The number of the discharge electrodes 2b is 107, the pitch p between the discharge electrodes 2b is 2 mm, and the tip of the discharge electrode 2b is placed on the insulating substrate 1b so as to project 2 mm from the edge of the insulating substrate 1b. Glued. Insulating substrate 1
A plurality of discharge electrodes 2b '(hereinafter, referred to as a second discharge electrode array), a common electrode 13b' (not shown), and a chip resistor 16b 'are also arranged on the back surface of the b in the same configuration as the front surface.
The common electrodes 13b and 13b 'are connected to voltage power supplies 7 and 8, respectively. As shown in FIG. 15, the voltage waveforms applied from the voltage power supplies 7 and 8 to the first and second discharge electrode arrays are binary values of the driving voltage (-2.5 kV) and 0 V (ground state). Is a rectangular wave having a duty of 50% and having a phase shifted by an appropriate degree (a phase shifted by 180 ° is most preferable). That is, a driving voltage (-2.5 kV) is applied to the first discharge electrode row, and when in the discharge state, the adjacent second discharge electrode row is grounded. Item 1 plays a role similar to that of the auxiliary electrode in the invention, so that the discharge of the first discharge electrode row is stabilized and uniform, and the uniformity of charging can be improved.
The driving voltage can be reduced. Similarly, when a driving voltage is applied to the second discharge electrode row and the discharge state is in effect, the discharge from the second discharge electrode row is stabilized because the first discharge electrode row serves as an auxiliary electrode. This makes it possible to improve the uniformity of charging, improve the uniformity of charging, and reduce driving voltage. The voltage waveform is not limited to this, but may be any waveform having a vibration waveform such as a sine wave or a pulse wave. Further, as shown in FIG. 16, the first discharge electrode row and the second discharge electrode row are attached to the insulating substrate 1b so as to be shifted from each other by の of the discharge electrode pitch p, so that the Can be narrowed to p / 2 (1 mm), thereby further reducing the driving voltage and improving the charging uniformity. According to the corona discharge device of the present invention, 2
One of the discharge electrode rows is in a discharge state
In some cases, the second row of discharge electrodes acts as an auxiliary electrode
When the second discharge electrode row is in the discharge state, the first
Since the discharge electrode array acts as an auxiliary electrode, charging uniformity
And no grid electrode or shield case is required
As a result, high charging efficiency is obtained and the amount of generated ozone is small.
As well as downsizing of the device and reduced driving voltage
Can be Also, a first discharge electrode row and a second discharge electrode row
When mounted with the pitch shifted by 1/2 of the pitch
Then, since the apparent discharge electrode pitch is halved,
The discharge gap can be narrowed, further increasing the drive voltage
It is possible to realize reduction and improvement of charging uniformity. ## EQU00003 ## [0063]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of a corona discharge device according to one embodiment of the present invention. 2A is a perspective view of a discharge / auxiliary electrode portion of the corona discharge device of the present application, and FIG. 2B is a front view of a discharge electrode portion. 3A is a cross-sectional view (a) and FIG. 2B is a cross-sectional view of FIG. FIG. 4 is an equivalent electric circuit diagram of a corona discharge device according to one embodiment of the present invention. FIG. 5 is a diagram showing the relationship between charging characteristics and air gap impedance depending on the presence or absence of an auxiliary electrode. FIG. 6 is a diagram showing an experimental result of examining charging characteristics depending on the presence or absence of an auxiliary electrode. FIG. 7 is a diagram showing a relationship between a distance between an auxiliary electrode and a discharge electrode and a variation in charging current Ig. FIG. 8 is a diagram showing a relationship between a distance between an auxiliary electrode and a discharge electrode and charging characteristics. FIG. 9 is a diagram showing a relationship between a discharge gap and charging current variation. FIG. 10 is a diagram showing a relationship between a discharge gap and charging characteristics. FIG. 11 is a diagram showing a relationship between (discharge electrode pitch) / (discharge gap) and charging characteristics. FIGS. 12A and 12B are explanatory diagrams of a relationship between a control method of a corona discharge device and charging characteristics. FIG. 13 is a schematic configuration diagram of a corona discharge device according to a second embodiment. 14A is a perspective view of an electrode part of a corona discharge device according to a second embodiment, and FIG. 14B is a front view of the electrode part. FIG. 15 is a diagram showing voltage waveforms applied to first and second discharge electrode arrays. FIG. 16 is an explanatory diagram showing a state where the first discharge electrode row and the second discharge electrode row are shifted by １ ／ of the discharge electrode pitch p. 17A is a configuration diagram of a conventional corona discharge device, and FIG. 17B is an enlarged view of a discharge electrode unit. 18A is a diagram showing a model of the corona discharge device using the conventional sawtooth discharge electrode shown in FIG. 17A, FIG. 18B is a diagram showing the discharge characteristics thereof, FIG. [Description of Signs] 1a, 1b Insulating substrates 2a, 2b, 2b 'Discharge electrodes 13a, 13b, common electrodes 16a, 16b, 16b' Chip resistors 18a, 19a Auxiliary electrodes

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Sawai 22-22, Nagaikecho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Inventor Yoshihiro Tamura 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation (56) References JP-A-48-78939 (JP, A) JP-A-62-240981 (JP, A) JP-A-5-107876 (JP, A) JP-A-4-75297 (JP, A) JP-A-5-2314 (JP, A) JP-A-5-249807 (JP, A) JP-B-54-42768 (JP, B1) JP-B-55-15278 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01T 19/00-19/04 G03G 15/02

Claims (1)

(57) [Claim 1] A plurality of sawtooth-shaped discharge electrodes provided in the axial direction of a photoconductor for discharging a photoconductor are provided on both sides of an insulating substrate.
The first and second discharge electrode rows are provided as the first and second discharge electrode rows.
Each of the discharge electrode rows has a resistor having a predetermined resistance value.
Corona discharge device connected to a voltage power supply via
Te, the first and second discharge to the electrode column voltage is a vibration waveform
Is applied, and one of the first and second discharge electrode rows is supplemented.
In order to fulfill the function as an auxiliary electrode,
A corona discharge device, wherein voltages are applied with phases shifted from each other .