JPH05312892A - Corona current measurement - Google Patents

Abstract

PURPOSE:To provide a corona current measurement capable of measuring distribution of current with a high accuracy with a simple constitution. CONSTITUTION:A planar or cylindrical plate 21 having a plurality of electrodes of long narrow shape is positioned in parallel with a wire 24, and high voltage is impressed thereto from a high voltage power source. The electrodes 23 are insulation disposed at a minute space in parallel with the wire 24, and have substantially the same size with the wire 24. Corona current flowing in each electrode 23 is input to ammeter 29 through a switch as well as lead 27 and measured thereby. With such a constitution, a high current value is obtained and a high accuracy measurement is made possible, and further shortening of measuring time and wide cost reduction of measuring device through the simplification are achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic recording system applied to a copying machine, a laser printer or the like, and more specifically to measuring a corona discharge current of a charging device or a transfer device of an electrophotographic recording device. For measuring instruments for.

[0002]

2. Description of the Related Art In recent years, the spread of copying machines and laser printers has been extremely remarkable. Electrophotographic recording devices are used in these copying machines and laser printers.
Such a device is equipped with a charger and a transfer device,
The corona discharge by the charger is used to copy or print on the photoconductor. Therefore, it is very important to understand the distribution state of this corona discharge current, and a measurement and evaluation system for measuring the corona discharge current flowing into the photoconductor is required. However, since it is difficult to directly measure the corona discharge current flowing into the photoconductor, a corona current measuring instrument is used to measure and evaluate the distribution of this corona discharge current. Needless to say, it is desirable that such a measuring device has a simple structure, is low in cost, and has high measurement accuracy. For this reason, the measurement and evaluation system is being improved daily.

Now, regarding the configuration of such a conventional measuring device for corona discharge current, for example, Photographic Scien
ce and Engineering · Vor.28, Num. 3, May / Jun 1984
The paper “The Negati by PJ Walsh et al.
ve Corona Current Distribution for a Long Pin-to-P
lane Geometry ”.

A conventional technique will be described below with reference to the drawings. Fig. 6 is the P.102 Fig. Of the above paper by PJ Walsh et al.
Fig. 4 is an external perspective view showing the configuration of the conventional corona current measuring device proposed in Fig. 4, and Fig. 7 is a graph showing an example of the corona current measurement results, which is also shown in Fig. 5 of the above paper. is there.

In FIG. 6, a flat conductive plate 1
A probe 2 for current detection, which is insulated from the plate 1 with a minute gap and has a minute surface element, is embedded in the central part of. The conductive plate 1 is loaded on an X table 3 which moves the plate 1 in the X direction, and the X table 3 is loaded on a Y table 4 which moves the plate 1 in the Y direction. Has been done. Each of the X table 3 and the Y table 4 has a potentiometer 5 for detecting its position, and the potentiometer 5 is connected to a recorder 6, respectively. On the other hand, the probe 2 is connected to the recorder 6 via the ammeter 7. As a result, the recorder 6 can record the current density distribution with respect to the position in the X direction or the Y direction. Further, a corona discharge needle electrode 9 is arranged at a position corresponding to the plate 1, and the needle electrode 9 is supported by a T-shaped support 10. The T-shaped support 10 is connected to the high voltage DC power supply 11. The needle electrode 9 and the plate 1 constitute a needle-to-plate electrode corona discharge system.

Next, the operation of the conventional corona current measuring device shown in FIG. 6 will be described with reference to FIG. Figure 7
The horizontal axis represents the amount of movement in the X or Y direction (X direction in the figure), and the vertical axis represents the corona current density. Point 0 represents the line including probe 2. In FIG. 6, a high voltage is applied between the needle electrode 9 and the plate 1 from a high voltage DC power supply 11. As a result, a corona discharge current flows from the tip of the needle electrode 9 toward the plate 1, but the current distribution can be measured by the microprobe 2 for grasping the property. That is, the plate 1 in which the probe 2 is embedded moves in the X and Y directions in the horizontal plane by the X, Y tables 3 and 4 according to the position command of the potentiometer 5. Thereby, the current density distribution on the plate surface can be measured. The probe 2 is connected to the ammeter 7, and the output of the ammeter 7 is recorded by the recorder 6 in conjunction with the position information of the potentiometer 5. FIG. 7 shows an example thereof, and, for example, the corona current density when the probe 2 is moved by moving the X table in the positive and negative directions centering directly under the needle electrode 9 and measured is recorded. The measuring device shown in FIG. 6 relates to a stylus-to-plate corona discharge system, but the stylus is a wire parallel to the plate or surrounds the wire such as a charger or a transfer device of an electrophotographic recording device. Even in a measuring device such as a corona discharger provided with a shield electrode, the above-mentioned configuration and operation are almost the same.

[0007]

Since the conventional corona current measuring device is constructed as described above, it is necessary to measure the current with a micro surface element, and therefore the measurement accuracy is not good. Had a point. Therefore, in order to improve the measurement accuracy, it is necessary to use a high-sensitivity ammeter and take measures against deterioration of the measurement accuracy. Also,
In order to measure the current density distribution on the plate surface, a moving device that moves a probe having a minute surface element in the X and Y directions is required, which makes the device very complicated and very costly. It has to be an expensive device,
The above-mentioned conventional measuring device has various problems.

The present invention has been made to solve the above-mentioned problems, and has a simple structure capable of measuring a current density distribution with high accuracy and not requiring a plate moving device. The purpose is to provide an inexpensive corona current measuring device.

[0009]

In the corona current measuring device according to the present invention, a high voltage is applied between a discharge wire having an elongated shape and a flat or curved electrode facing the discharge wire. A corona current measuring device for measuring the distribution of a corona discharge current sometimes generated on the electrode,
(i) a high voltage power supply that applies a high voltage to the discharge wire, and (ii)
A planar or curved surface electrode formed by a plurality of elongated oblong electrodes arranged in parallel with the discharge wire and regularly insulated with a small interval in a direction perpendicular to the discharge wire; Measuring means for measuring a corona current flowing through each of the long electrodes.

A corona current measuring instrument according to a second aspect of the present invention is the corona current measuring instrument according to the first aspect, in which the length of the eccentric electrode is equal to or less than the length of the discharge wire and both ends of the discharge wire are It is characterized in that auxiliary electrodes are arranged in a direction perpendicular to the discharge wire in a region facing the section to form a surface electrode.

[0011]

In the corona current measuring device according to the first aspect of the invention, the corona current according to the distance from the discharge wire flows through each of the elongated electrodes, and the current value is measured.

In the corona current measuring device according to the second aspect of the present invention, since the auxiliary electrode is provided, the influence from the both ends of the discharge wire in the current flowing into each elongated electrode is reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing an outline of a corona current measuring device showing a first embodiment of the present invention, and FIG. 2 is a front view of a plate on which electrodes used in the measuring device of FIG. 1 are formed,
FIG. 3 is a cross-sectional view showing the relationship between the plate and the wire in FIG.

An electrode 23 is formed on the upper surface of the substrate 22 to form the plate 21. The plate 21 corresponds to, for example, a photoconductor in a copying machine. The board 22 is made of an insulating material such as a circuit board and has a planar shape in the embodiment. The electrodes 23 are formed in an elongated band shape on the substrate 22, and a plurality of electrodes 23 are arranged in parallel and continuously at a small interval in the X-axis direction. Discharge wires 24 as chargers are arranged on the plate 21 in parallel with the plate 21 with a certain distance. As a result, the electrode 23 is arranged in parallel with the wire 24 at a constant interval (that is, it has a rectangular shape elongated in the Y-axis direction). In the first embodiment, the length of the electrode 23 is formed to be substantially the same as the length of the discharge portion of the wire 24. The wire 24 is connected to the high-voltage power supply 25, and the high-voltage power supply 25 is grounded to the ground 26 so that the wire 24
A high voltage is applied to, and a corona current is generated in the electrode 23 due to the discharge from the wire 24. A lead wire 27 is connected to each strip-shaped electrode 23, and is connected to one terminal 29 a of an ammeter 29 via a switch 28. The other terminal 29b of the ammeter 29 is grounded to the earth 26. In the switch 28, each electrode 23 is sequentially connected to the terminal 29a.
It has a rotary switch configuration so that it can be connected to.

Next, the operation of the first embodiment will be described. When a high voltage is applied from the high voltage power supply 25 between the wire 24 and the electrode 23 of the plate 21, a corona current flows through each electrode 23 due to the discharge from the wire 24. Here, the switch 28 is operated so that, for example, the electrode 23 and the terminal 2 are sequentially arranged in the X direction (direction perpendicular to the wire 24) shown in the figure.
9a is connected. Then, the corona current flowing through each electrode 23 can be measured by the ammeter 29 via the lead wire 27. As a result, the current density distribution on the surface of the plate 21 can be measured and the wire 24 can be evaluated. By plotting the data of the ammeter 29 on a recorder (not shown), the distribution state of the corona current density as shown in FIG. 7 can be graphed and recorded.

FIG. 4 is a front view of a plate showing a second embodiment of the present invention. The feature of the second embodiment is that an elongated strip-shaped electrode 33 is provided on a substrate 32 which constitutes the plate 31.
Is parallel to the wire 24 but shorter than the wire 24. Then, two auxiliary electrodes 34 each formed of one conductive member are formed in both end regions of the substrate 32 in the Y direction. The auxiliary electrode 34 has a length in the direction perpendicular to the wire 24. That is, a plurality of oblong strip electrodes 33 are provided on the plate 31.
And the two auxiliary electrodes 34 are formed.
The auxiliary electrode 34 corrects the effect of reducing the effect of the current flowing from both ends of the wire 24 in the current flowing into the strip-shaped electrode 33, whereby the measurement accuracy of the corona current can be further improved.

FIG. 5 is a sectional view showing the principle of the corona current measuring device according to the third embodiment of the present invention. The configuration of FIG.
A shield electrode 35 is formed on a wire 24 arranged in parallel with an elongated strip electrode 23 formed on a substrate 22 constituting the plate 21 shown in FIG. 3 so as to surround the wire 24 on three sides. Is what Such a structure is a structure used as a normal charger or transfer device called a corotron or a scorotron,
It goes without saying that the present invention can be applied to such a device.

By the way, in this embodiment, the substrate 22 is formed into a flat plate and is a flat plate. However, the present invention is not limited to this, and any insulating material may be used in the electrophotographic recording apparatus. A cylindrical one like a drum,
It is possible to select a shell shape having the same curvature as that of the photosensitive drum from a position right below the wire to a vertical distance, or any other shape without changing the gist. Also, regarding the electrodes, in the present embodiment, the case where the strip-shaped electrodes having the same area and having an elongated shape have been described, but it goes without saying that the areas of the electrodes may be different. That is, various areas such as sequentially increasing the area from the electrode directly below the wire, or configuring the area ratio according to the magnitude of the current to be measured, or configuring with a cylindrical or other cross-sectional shape The shape is conceivable.

Now, a method of forming the electrodes of the plate will be described with reference to FIG. One of them is that a conductive member is formed on the substrate 22 by plating or vapor deposition to form a single film, and the film is covered with a resist, and necessary treatment such as exposure is performed so that the electrodes remain, and then an etching solution is used. It is a method of obtaining an electrode 23 as shown in FIG. When the resist is finally removed, the required plate 21 can be obtained. The electrode 23 is generally formed by such an etching method, but it can also be formed by the following method. That is, a conductive member is formed on the substrate 22 by plating or vapor deposition, and a portion of the unnecessary conductive member is irradiated with a beam of ions or the like. Then, the necessary conductive member remains and becomes the electrode 23 to complete the plate. According to such a beam processing method, extremely precise processing is possible. Furthermore, an electrode 23 is formed by forming an elongated strip-shaped conductive member in advance and forming a necessary space on a non-conductive substrate 22 such as a circuit board and bonding the gap.
As described above, the plate according to the present invention can be manufactured by various methods.

[0020]

As described above, according to the present invention, since the long strip-shaped electrode having a large area is used for current detection, a large current value can be obtained and a high-sensitivity ammeter is used. It has become possible to perform high-precision measurements without having to do so. Also, since a large number of strip electrodes are arranged,
A device such as an XY table for moving the plate or the wire becomes unnecessary, and the positional error due to the movement is almost eliminated. As a result, the measurement accuracy can be improved and the measurement time can be shortened. Further, since the moving device is not required, the device can be simplified and the cost of the measuring device can be significantly reduced. Therefore, it has a great effect on the improvement of the measurement accuracy and the cost reduction of the corona current measuring device.

[Brief description of drawings]

FIG. 1 is an external perspective view showing the outline of a corona current measuring instrument showing a first embodiment of the present invention.

FIG. 2 is a front view of a plate on which an electrode used in the measuring device of FIG. 1 is formed.

3 is a cross-sectional view showing a relationship between a plate and a wire used in the measuring device of FIG.

FIG. 4 is a front view of a plate showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing a relationship between a plate and a wire, which shows the principle of a corona current measuring device according to a third embodiment of the present invention.

FIG. 6 is an external perspective view showing the configuration of a conventional corona current measuring device.

FIG. 7 is a graph showing an example of a corona current measurement result.

[Explanation of symbols]

 21, 31 Plate 22, 32 Substrate 23, 33 Electrode 24 Wire 25 High-voltage power supply 27 Lead wire 28 Switch 29 Ammeter 34 Auxiliary electrode 35 Shield electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsuya Kunieda 8-1-1 Tsukaguchihonmachi, Amagasaki-shi, Hyogo Sanryo Electric Co., Ltd.

Claims (2)

[Claims] 1. A method for measuring the distribution of a corona discharge current generated on an electrode when a high voltage is applied between an elongated discharge wire and a flat or curved electrode facing the discharge wire. A corona current measuring instrument, comprising: a high-voltage power supply for applying a high voltage to the discharge wire; a plurality of high-voltage power supplies, which are arranged in parallel with the discharge wire and are regularly insulated from the discharge wire at small intervals in a vertical direction. 2. A corona current measuring instrument, comprising: a planar or curved surface electrode formed by the elongated elongated electrode of claim 1; and a measuring unit that measures a corona current flowing through each of the elongated electrodes. 2. The length of the eccentric electrode is set to be equal to or less than the length of the discharge wire, and auxiliary electrodes are respectively arranged in a region facing both ends of the discharge wire in a direction perpendicular to the discharge wire. The corona current measuring device according to claim 1, wherein an electrode is formed.