JPH06273465A - Potential measuring device - Google Patents

Abstract

PURPOSE:To prevent discharge from occuring, measure a potentialat a small region in noncontact state, and achieve miniaturization of the device by providing a measurement probe, an electrical element, and a charge measurement means. CONSTITUTION:After a measurement probe 1 is brought closer to the object at the grounding potential, the probe 1 is brought closer to a potential measurement surface 2. At this time, the charge determined by air between the probe 1 and the measurement surface 2 and the amount of static electricity of an electrical element 3, the potential, etc., of the measurement surface 2, flows into or flows out of the measurement surface 2 via an element 3, the probe 1, and an insulation substance 1a from a constant potential source 4. A charge measurement means 5 measures the potential of the measurement surface 2 by detecting the amount of charge entering or escaping from the element 3. The substance 1a is sealed to the tip of the probe 1, thus preventing discharge and measuring the potential of a small region without any contact. Also, since the configuration of the probe 1 is extremely simple, the device can be miniaturized easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a potential measuring device capable of measuring potential in a minute area.

[0002]

2. Description of the Related Art Conventionally, as a potential measuring device, a surface utilizing the fact that an alternating current of a magnitude corresponding to the surface potential of the measured object flows to the measured electrode by bringing the detected electrode closer to the measured object while vibrating the surface. The potential sensor is ultrasonic TECHNO
August issue, pp. 56-60.

[0003]

At present, in a dry plain paper copying machine, a facsimile or the like, high image quality is an important issue together with cost reduction, size reduction and noise reduction.
In the case of dry plain paper copiers and facsimiles using electrophotographic technology, one solution for improving image quality is to measure the surface potential distribution of the photoconductor after charging and after exposure with high resolution. However, it is conceivable to perform various controls based on that. For that purpose, a small device capable of measuring the surface potential of a minute region of the photoconductor is required.

[0004] The potential measuring device can increase the resolution to some extent even if the surface electrometer, which is the mainstream at present, is downsized, but the structure is rather complicated, and therefore there is only a limit to downsizing. However, there is a problem in that the output becomes small when the size is reduced and the measurement accuracy is lowered. Therefore, the current surface electrometer cannot measure the surface potential of a minute area, and cannot measure the high-resolution surface potential distribution.

An object of the present invention is to improve the above-mentioned drawbacks and to provide an electric potential measuring device capable of measuring electric potential in a minute area.

[0006]

In order to achieve the above object, the invention according to claim 1 is located at a minute interval with respect to the potential measuring surface and at least a portion facing the potential measuring surface. Having a conductive measuring probe having an insulating substance attached to the inner surface, an electric element connected between the measuring probe and a constant potential source, and a charge measuring means for measuring electric charge going in and out of the electric element Is.

According to a second aspect of the present invention, there is provided a conductive measuring probe which is in contact with the potential measuring surface and at least a portion facing the potential measuring surface is provided with an insulating material, and the measuring probe and constant potential source. An electric element connected between the electric element and the electric element, and a charge measuring unit for measuring electric charge flowing in and out of the electric element.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the potential measuring device described above, a ferroelectric substance is fixed as an insulating substance to a portion of the measuring probe facing the potential measuring surface.

[0009]

According to the first aspect of the present invention, the conductive measuring probe is located at a minute distance from the potential measuring surface,
In addition, an insulating substance is attached to at least a portion facing the potential measurement surface. A charge flows between the potential measurement surface and the constant potential source through the insulating substance, the measurement probe, and the electric element, and the charge flowing in and out of the electric element is measured by the charge measuring means.

According to the second aspect of the present invention, the conductive measuring probe is in contact with the potential measuring surface, and at least a portion facing the potential measuring surface is provided with an insulating substance. A charge flows between the potential measurement surface and the constant potential source through the insulating substance, the measurement probe, and the electric element, and the charge flowing in and out of the electric element is measured by the charge measuring means.

According to a third aspect of the invention, in the potential measuring device according to the first or second aspect, electric charges flow between the potential measuring surface and the constant potential source through the ferroelectric substance, the measuring probe and the electric element.

[0012]

FIG. 1 shows a first embodiment of the present invention. The measuring probe 1 is arranged so as to face the potential measuring surface 2 with a minute gap therebetween, and an insulating material 1a such as resin or ceramic is fixed to the tip end facing the potential measuring surface 2.
Further, the measurement probe 1 has a constant potential source 4 through an electric element 3 including a switch element, a resistance element, a capacitor and the like.
Connected to. A charge measuring means 5 is connected to the electric element 3, and the electric charge passing through the electric element 3 is measured by the charge measuring means 5. Here, the space between the measurement probe 1 and the potential measurement surface 2 forms a kind of capacitor, and its capacitance C is the area on the potential measurement surface 2 side of the measurement probe 1, the measurement probe 1 and the potential measurement surface. Determined by the gap length between the two.

Next, the operation of the first embodiment will be described.
After bringing the measurement probe 1 close to an object at ground potential,
When the measurement probe 1 is brought close to the potential measurement surface 2 as shown in FIG. 3, the charge Q determined by the gap between the measurement probe 1 and the potential measurement surface 2, the capacitance of the electric element 3, the potential V of the potential measurement surface 2, and the like. From the constant potential source 4 flows into or out of the potential measurement surface 2 through the electric element 3, the measurement probe 1, and the insulating substance 1a. The charge measuring means 5 detects the amount of charge Q entering and leaving the electric element 3 to detect the potential measuring surface 2
The potential V of is measured.

FIG. 2 shows a concrete structure of the first embodiment. A switch 6 is used as the electric element 3, and an ammeter 7 is used as the charge measuring means 5. The measurement probe 1 is connected via a switch 6 and an ammeter 7 to a ground point forming a constant potential source 4. When the switch 6 is turned on, the insulating material 1a, the measurement probe 1, the switch 6,
A current flows through the ammeter 7 to the ground point, and this current is measured by the ammeter 7 and integrated, whereby the charge amount Q flowing in and out of the electric element 3 is detected, and the potential V of the potential measuring surface 2 is detected.
Is measured.

In the first embodiment, since the insulating substance 1a is fixed to the tip of the measuring probe 1, it is difficult to discharge and the potential of a minute area can be measured without contact. Moreover, since the configuration of the measurement probe 1 is very simple, it is suitable for downsizing.

FIG. 3 shows a second embodiment of the present invention. In the second embodiment, a switch 6 and a resistance element 8 are used as the electric element 3 and a voltmeter 9 is used as the charge measuring means 5 in the first embodiment. The measurement probe 1 is connected to the ground point 4 via the switch 6 and the resistance element 8,
The voltmeter 9 is connected in parallel with the resistance element 8.

When the switch 6 is turned on, the insulating substance 1a, the measuring probe 1, the switch 6,
Electric charges flow to the ground point through the resistance element 8, and the voltage across the resistance element 8 is measured by the voltmeter 9 and integrated, whereby the charge amount Q flowing in and out of the electric element 3 is detected and the potential is measured. The potential V on surface 2 is measured. In the second embodiment, as in the first embodiment, it is possible to measure the electric potential in a minute area in a non-contact manner, and the configuration of the measuring probe 1 is very simple and suitable for miniaturization.

In the first and second embodiments described above, the insulating substance 1a is fixed to the tip of the measuring probe 1. However, when the insulating substance 1a has a low potential on the potential measuring surface 2, It is not necessary when the measurement probe 1 can be separated from the potential measurement surface 2 to some extent because low-resolution potential measurement is sufficient.
However, in order to measure the electric potential with high resolution, it is necessary to bring the measuring probe 1 close to the electric potential measuring surface 2,
By fixing the insulating substance 1a to the tip portion of the measurement probe 1, it is possible to obtain the effect that the electric potential can be measured while avoiding the discharge.

FIG. 4 shows a third embodiment of the present invention. The measurement probe 11 is arranged in contact with the potential measuring surface 12, and an insulating material 11a such as resin or ceramic is fixed to the tip end portion on the potential measuring surface 12 side. Also, the measurement probe 1
1 is connected to a constant potential source 14 via an electric element 13 composed of a switch element, a resistance element, a capacitor and the like.
A charge measuring means 15 is connected to the electric element 13, and the electric charge passing through the electric element 13 is measured by the charge measuring means 15. Here, since the insulating substance 11a is interposed between the measuring probe 11 and the potential measuring surface 12, the insulating substance 11a forms a kind of capacitor and its capacitance C
Is determined by the material, thickness, area, etc. of the insulating substance 11a.

Next, the operation of the third embodiment will be described.
After bringing the measurement probe 11 into contact with an object of ground potential,
When the measuring probe 11 is brought into contact with the potential measuring surface 12 as shown in FIG. 4, the electric charge Q determined by the capacitance of the insulating substance 11a and the potential V of the potential measuring surface 12 is supplied to the constant potential source 1.
4 flows into or out of the electric potential measuring surface 12 through the electric element 13, the measuring probe 11, and the insulating material 11a. The electric charge measuring means 15 measures the electric potential V of the electric potential measuring surface 12 by detecting the electric charge amount Q flowing in and out of the electric element 3.

FIG. 5 shows a concrete structure of the third embodiment. A switch 16 and a capacitor 17 are used as the electric element 13, and a switch 18 and an ammeter 19 are used as the charge measuring means 15. The measurement probe 11 is connected via a switch 16 and a capacitor 17 to a ground point forming the constant potential source 14, and an ammeter 19 is connected in parallel with the capacitor 17 via a switch 18.

When the switch 16 is turned on and the switch 18 is turned off, the insulating material 11 is removed from the potential measuring surface 12.
a, measuring probe 11, switch 16, condenser 17
An electric charge flows to the grounding point via the
1a and the electrostatic capacity of the capacitor 17, and the electric charge according to the electric potential of the electric potential measuring surface 12. Next, when the switch 16 is turned off and the switch 18 is turned on, the capacitor 17 discharges through the switch 18 and the ammeter 19, and the discharge current is measured by the ammeter 19 and integrated, whereby the electric element 13 is discharged. The amount Q of electric charges flowing in and out is detected and the electric potential V of the electric potential measuring surface 12 is measured.

In the third embodiment, since the measuring probe 11 is brought into contact with the potential measuring surface 12 via the insulating substance 11a to measure the potential, it is possible to measure the potential in a minute area. Further, the configuration of the measurement probe 11 is very simple and suitable for miniaturization, and it is not necessary to control or measure a minute gap between the insulating substance 11a and the potential measurement surface 12.

FIG. 6 shows a fourth embodiment of the present invention. In the fourth embodiment, the constant potential source 14 is used in the third embodiment.
A DC probe 20 is used as the measuring probe 11 and the measuring probe 11 is connected to the DC probe 20 via the switch 16 and the capacitor 17. A switch 21 and a voltmeter 22 are used as the charge measuring means 5, and the voltmeter 22 is connected via the switch 21. Connected in parallel to the capacitor 17.

When the switch 16 is turned on and the switch 21 is turned off, the insulating material 11a from the DC power source 20
An electric charge flows through the potential measuring surface 12 through the measuring probe 11, the switch 16 and the capacitor 17 to charge the capacitor 17, and this electric charge is applied to the insulating substance 11a and the capacitor 1.
The electric charge is in accordance with the capacitance of No. 7, the potential of the potential measurement surface 12, and the voltage of the DC power supply 21. Next, when the switch 16 is turned off and the switch 18 is turned on, the voltage across the capacitor 17 is measured by the voltmeter 22 via the switch 21 and integrated, so that the amount of charge flowing in and out of the electric element 13 is increased. Q is detected and the potential V of the potential measuring surface 12 is measured.

In the fourth embodiment, as in the third embodiment, it is possible to measure the electric potential in a minute area, and the structure of the measuring probe 11 is very simple and suitable for miniaturization, and the insulating material 11a is used. It becomes unnecessary to control or measure a minute gap between the potential measuring surface 12 and the potential measuring surface 12.

In the third and fourth embodiments described above, if a material having a large dielectric constant such as a ferroelectric material is used as the material of the insulating material 11a, it is possible to obtain a large output in addition to being difficult to discharge. , The measurement accuracy is improved. The reason is,
When a material having a large dielectric constant is used as the material of the insulating material 11a, the capacitance of the capacitor formed by the insulating material 11a between the measurement probe 11 and the potential measurement surface 12 becomes large, and a large amount of charge is generated. This is because not only is it difficult to discharge, but also a large output can be obtained and potential measurement can be performed with high accuracy.

The present invention is not limited to the above embodiment, but capacitors and resistance elements may be used as the electric elements 3 and 13, and the current and voltage at the time of charging the capacitor 17 may be measured. You can

[0029]

As described above, according to the first aspect of the present invention, the insulating substance is located at a minute distance from the potential measuring surface and at least the portion facing the potential measuring surface is covered with the insulating substance. Since it is provided with a conductive measuring probe having an electric element connected between the measuring probe and a constant potential source, and a charge measuring means for measuring electric charge going in and out of the electric element, it is difficult to discharge, The potential of a minute area can be measured without contact. Moreover, the configuration of the measurement probe is very simple, which is suitable for downsizing.

According to the second aspect of the present invention, a conductive measuring probe which is in contact with the potential measuring surface and at least a portion facing the potential measuring surface is provided with an insulating substance, and the measuring probe is fixed. Since the electric element connected between the electric source and the electric potential source and the electric charge measuring means for measuring the electric charge flowing in and out of the electric element are provided, the electric potential in a minute area can be measured, and the structure of the measuring probe is very high. It is simple and suitable for miniaturization, and it eliminates the need to control or measure the minute gap between the insulating material and the potential measurement surface.

According to the third aspect of the invention, in the potential measuring device according to the first or second aspect, since the ferroelectric substance is fixed as an insulating substance to the portion of the measuring probe facing the potential measuring surface, the discharge is performed. It is difficult to do so and a large output can be obtained, and the measurement accuracy is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram specifically showing the first embodiment.

FIG. 3 is a circuit diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a third embodiment of the present invention.

FIG. 5 is a circuit diagram specifically showing the third embodiment.

FIG. 6 is a circuit diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1,11 Measuring probe 1a, 11a Insulating material 2,12 Potential measuring surface 3,13 Electric element 4,14,20 Constant potential source 5,15 Charge measuring means 6,16,18,21 Switch 7,19 Ammeter 8 Resistance element 9,22 Voltmeter 17 Capacitor

Claims (3)

[Claims] 1. A conductive measuring probe which is located at a minute distance from the potential measuring surface and has an insulating substance at least at a portion facing the potential measuring surface, and the measuring probe. An electrical element connected between the potential source and
An electric potential measuring device comprising: an electric charge measuring means for measuring an electric charge flowing in and out of the electric element. 2. A conductive measuring probe which is in contact with the potential measuring surface and has an insulating substance at least at a portion facing the potential measuring surface, and is connected between the measuring probe and a constant potential source. An electric potential measuring device, comprising: an electric element, and an electric charge measuring means for measuring an electric charge flowing in and out of the electric element. 3. A potential measuring device according to claim 1, wherein a ferroelectric substance is fixed as an insulating substance to a portion of the measuring probe facing the potential measuring surface.