JPH01276160A - Corona ion generating device - Google Patents

Abstract

PURPOSE:To control corona ion generation with a low control voltage by controlling the intensity of an electric field nearby an electrode for corona ion generation by a control electrode provided behind a dielectric, and controlling the corona ion generation itself. CONSTITUTION:When a negative potential is applied to the control electrode 5 provided behind the dielectric plate 1, the equal potential surface of the negative voltage moves toward the control electrode 5 and the intensity of the electric field nearby the corona ion generating electrode 3 increases greatly to generate corona ions having the negative polarity from nearby the electrode 3. Further, the control electrode 5 applies a smaller negative voltage to reduce the potential difference between the control electrode 5 and corona ion generating electrode 2, and consequently the electric field nearby the corona ion generating electrode 3 applied with a negative high voltage decreases in intensity, so that the generation of corona ions is stopped. Thus the intensity of the electric field nearby the corona ion generating electrode 3 is controlled directly to control the corona ion generation itself, thereby controlling the corona ion generation with the low control voltage.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to a corona ion generator used for electrostatic recording using corona ions in printers, copiers, etc. An object of the present invention is to provide a novel corona ion generator that can efficiently generate corona ions at a low voltage and can control the generation of corona ions at a low voltage.

(Prior Art) Conventional electrostatic recording methods using corona ions include an electrophotographic method and a method of controlling a corona ion flow to obtain an electrostatic latent image. Electrophotography involves uniformly charging a photoreceptor with corona ions, irradiating it with light to obtain an electrostatic latent image, and developing it with colored particles (toner) that have a charge opposite to that of the electrostatic latent image. It is something to visualize. The corona ion generator used here consists of a thin wire of about 60 microns and a 10+ wire surrounding it.
It consists of electrodes separated by about m, and is used with a part of the electrodes opened. At this time, the voltage applied to the wire is 5■
A relatively high voltage is required. Furthermore, since only the ions coming out of the openings out of the corona ions generated around the wire are used, the efficiency is low and a large amount of wasted ozone etc. is generated.

On the other hand, a method of controlling a corona ion flow to obtain an electrostatic latent image is composed of the corona charger and a control electrode having a penetrating ion flow passage hole provided in an opening and corresponding to a recording dot. The corona ion flow is controlled by a signal voltage applied to this control electrode, and an electrostatic latent image is formed on a dielectric material or electrostatic recording paper. In this case as well, the corona ion generator requires high voltage and generates a large amount of ozone, etc., and the recording dot is small, which further deteriorates the utilization efficiency of corona ions and makes it impossible to obtain sufficient corona ion density. There was a speed limit. In order to eliminate these drawbacks, we proposed a new solid-state corona ion generator that can use a low voltage for corona generation and generates corona ions only in the direction of the opening (Japanese Patent Laid-Open No. 184562/1983).
(Japanese Patent Laid-Open No. 61-286863). We also presented a prototype of a device based on the same idea (3rd Non-Impact Printing Technology Symposium Proceedings S6
1.7.24). This basic principle is based on increasing the electric field strength by bringing the wire of the corona ion generator extremely close to the peripheral electrode.

Therefore, an electrode equivalent to a wire and a peripheral electrode are placed between insulators and solidified on the same substrate, making it possible to obtain the strong electric field necessary for generating corona ions at a low voltage. In both proposals, positive and negative corona ions are generated by applying alternating current to prevent only the local part of the electrode from being filled with the same ions, and the control electrode uses only corona ions of one polarity. FIG. 4(a) shows the device disclosed in Japanese Patent Application Laid-Open No. 61-184562, in which electrodes (52) and (53) are provided on both sides of an insulating substrate (51), and the electrodes (53) are provided with a strong electric field. There are grooves or holes (54) that generate corona ions. This electrode (52)
(53), an AC voltage (54) lower in voltage than the conventional corona ion generator is applied. At this time, grooves or holes (5
4) A high electric field is generated in the region, and positive and negative corona ions are generated.

These corona ions are controlled by turning on and off the control voltage (55) applied to the electrode (53), and the generated corona ions are efficiently accelerated by the voltage (57) applied to the accelerating electrode (56). Photoreceptor or dielectric (58)
It reaches the top and is charged. Figure 4(b) is JP-A No. 6
1-286863, which has a dielectric layer (59)
and internal electrodes (60) and (61) provided therein.
An AC voltage (54) is applied between them. A discharge electrode (63) is provided on the surface of this internal electrode via a dielectric layer (62).

(64) is provided, and a voltage (65) serving both acceleration and control is applied to the electrode. The positive and negative corona ions generated by the electric field between the discharge electrode and the internal electrode are connected to the discharge electrode (63).
, (64), only the negative corona ions are accelerated by the accelerating voltage (65), and the photoreceptor or dielectric (64) is accelerated by the accelerating voltage (65).
6) Reach the top. Although the above methods have different structures, the basic operations are the same. The disadvantage of this corona ion generator is that although the AC power supply voltage for corona ion generation is reduced to about a fraction of that of conventional systems, the control voltage for turning on and off the generation of corona ions is limited to electrostatic latent images. A high voltage higher than the surface potential (600 V for a photoreceptor) that forms a voltage is required.

(Problems to be Solved by the Invention) Corona ion generators used in conventional electrophotography or electrostatic recording using corona ions require a high voltage of 5 KV or more. Recently, a solid-state corona ion device that generates corona ions at a voltage as low as 2 V has been proposed and developed, but a voltage of several hundred volts is required to control the corona ions. For this reason, electrostatic recording is performed by controlling corona ions to form dots, or in laser printer recording methods in which the surface potential is controlled line by line, a high-voltage IC is required for the drive circuit. This has hindered the widespread use of such dot-based electrostatic recording methods, and at present no method has been considered for controlling charging on a line-by-line basis in laser printers. An object of the present invention is to eliminate the above-mentioned drawbacks and provide a novel corona ion generator that makes it possible to control corona ions with a low control voltage.

[Structure of the invention]

(Means for Solving the Problem) The present invention focuses on the fact that the generation of corona ions can be controlled by controlling the electric field strength near the electrode for generating corona ions, and it is possible to control the generated corona ions as in the conventional method. Rather, the present invention provides a corona ion generator that directly controls the generation of corona ions by controlling the electric field near the electrode for generating corona ions. Its structure consists of a pair of corona ion generating electrodes provided on the same surface of the dielectric, and a control electrode provided on the back side of the dielectric that controls the electric field between the corona ion generating electrodes. It is a device. If necessary, another accelerating electrode may be provided on the corona ion generating electrode side. A DC or AC voltage for corona ions is applied between a pair of corona ion generating electrodes, a control voltage according to a signal is applied to the control electrode, and a constant accelerating voltage is applied to the accelerating electrode.

(Function) By using the corona ion generator according to the present invention, corona ions can be efficiently generated and corona ions can be controlled with a very low control voltage.

(Example) Next, the present invention will be explained in detail using the drawings. FIG. 1 is a schematic cross-sectional view of a corona ion generator according to the present invention.

A pair of corona ion generating electrodes ■ on the same side of one of the dielectric plates or insulator plates ω.

■ is installed across the gap (a). Unlike Canon et al.'s patent, the electrode for generating corona ions is provided on the same side of the dielectric plate, which allows the image electrode to exist in the air, which is the source of corona ions, and generates a strong electric field, thereby generating ions efficiently. be able to. A control electrode 0 is installed on the back surface of the dielectric in the gap. Further, an accelerating electrode 0 is provided on the same side as the corona ion generating electrodes ① and ②, separated by a certain distance. This accelerating electrode 0 has a slit shape or a through hole (2) corresponding to a recording dot, so that the generated corona ions can freely pass therethrough depending on the accelerating voltage. The corona ions that have passed through here reach the photoreceptor or dielectric (8) to form an electrostatic latent image through various processes. AC or DC voltage is applied to the corona ion generating electrodes (3). Unlike DC voltage, the application of AC voltage generates not only unipolar corona ions but also bipolar corona ions, which erases wasteful ions that were not used for recording and prevents space charges caused by generated ions, resulting in efficient ionization. This also prevents the electrode from becoming fatigued due to the generation of excess ozone, etc.゛One electrode for generating this corona ion■
A ground potential or bias voltage (■) is applied. In this example, since negative corona ions are generated, the bias voltage (■) is a negative voltage. - A corona ion control voltage (10) and an optimum bias voltage (11) determined by the thickness of the dielectric plate (2) and the gap (a) between the corona ion generating electrodes are applied to the force control electrode (2). Furthermore, an accelerating voltage (12) is applied to the accelerating electrode (Q. However,
This accelerating electrode (2) is not required when uniformly charging the photoreceptor.

Next, using Fig. 2, calculate the control voltage (
10) is a conceptual diagram of the equipotential surface (13) when a negative voltage is applied to the corona ion generating electrode (1) for generating negative corona ions.

At this time, the case where the corona ion generating electrode (2) is at earth potential will be explained. In Fig. 1(a), the control electrode 0
A negative potential is applied to. Then, the equipotential surface of the negative voltage moves toward the control electrode (2), the electric field strength near the corona ion generating electrode (2) increases significantly, and negative corona ions are generated from the vicinity of the electrode (2). This negative polarity corona ion moves toward the electrostatic recording medium due to the voltage applied to the accelerating electrode.

In order to efficiently move the negative polarity corona ions generated at this time toward the accelerating electrode, it is necessary to optimize the accelerating electrode arrangement and the applied voltage. Next, an outline of the equipotential surface when a smaller negative voltage is applied to the control electrode (2) to stop the generation of corona ions will be explained using FIG. 2(b). At this time, the potential difference between the control electrode (■) and the corona ion generating electrode (■) becomes small.

The electric field near the corona ion generating electrode ■, to which a negative high voltage is applied, weakens and the generation of corona ions stops.

Next, the control voltage required for the control 81 electrode (2) is derived by rough calculation. In the calculation, it is assumed that an electric field equivalent to the electric field between the corona ion generating electrodes can be generated between the control electrode ■ and the corona ion generating electrode ■, thereby affecting the electric field between the corona ion generating electrodes. be. For example, if the distance (L) between the corona ion generating electrodes is 100 microns, which corresponds to the size of the recording dot, the electrode thickness (a) is 100 microns.
When expressed in microns, the critical voltage (Eo) for generating corona ions between these two electrodes is given by the following equation.

The electric field (E) near the electrodes when a voltage va is applied between the corona ion generating electrodes is approximated by the following equation.

-L Eo =-17-1100X 10-' = v'' × (100×1O-4)2=■.X 1
0"> 126 (KV/cm), corona ions are generated by applying 1.26 KV between the corona ion generating electrodes. On the other hand, the thickness (d) of the dielectric plate 1 is
When expressed as microns, the electric field (ES) generated at the corona generating electrode by the voltage (VS) applied between the control electrode (1) and the corona generating electrode 0 can be approximately given by the following equation.

Valve V, . For example, the corona ion generation electrode voltage is 1.2
When the voltage is 6 KV, corona ion generation can be controlled by applying a voltage of about 126 V as the control voltage. This indicates that the value is only a few times smaller than the conventional method for controlling generated corona ions. The corona ion generator according to the present invention is actually manufactured by laminating layers on a thick substrate such as ceramics.

Next, a multihead for performing electrostatic recording using the present invention will be described with reference to FIG. Ceramic substrate (3
A control electrode array (32) corresponding to the image density of each recording dot is formed on the dotted line (1: dotted line) using a thin film forming technique such as sputtering. An insulating thin film (33) is provided thereon, and two corona ion generating electrodes (34) perpendicular to the control electrode array are further provided thereon. The accelerating electrode (3
6) is provided. An electrostatic recording paper (37) and a conductive roller (38) are installed on the back side of the electrostatic recording paper (37) facing the accelerating electrode. The voltage arrangement applied to each electrode is as shown in Figure 1, and a control signal corresponding to each recording pixel is given to the control electrode (32), and corona ions are generated at each pixel according to the signal. However, the corona ions that have passed through the accelerating electrode (36) form an electrostatic latent image on the electrostatic recording paper (37). This electrostatic latent image is visualized with toner by a developing device and fixed to form a fixed image.

The corona ion generator shown in these examples shows one example of the electrode configuration, and the generation of corona ions, which is the basic concept of the present invention, is performed by applying an electric field near the corona ion generating electrode to a low voltage. All controlled methods are included in the present invention.

〔Effect of the invention〕

As described above, according to the present invention, the generation of corona ions can be efficiently controlled with a low control voltage.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of the corona ion generating electrode according to the present invention, Fig. 2 is a diagram showing equipotential surface fluctuations due to the control electrode when corona is generated, and Fig. 3 is a diagram showing the corona ion generating device according to the present invention arranged in a multi-layered structure. FIG. 4 is a schematic cross-sectional view of a conventional low-voltage driven corona ion generator. 1... Insulator plate 2, 3... Corona ion generating electrode 5... Control electrode 6... Accelerating electrode 7... Corona ion passage hole 37... Electrostatic recording paper agent Patent attorney rules Ken Ken Chika Mitsuyuki Matsuyama Figure 1 Figure 2

Claims (3)

[Claims] (1) It has first and second electrodes for generating corona ions facing each other on the same dielectric surface, and a third electrode on the back side of the dielectric, and corona ions are generated between the first and second electrodes. A corona ion generator comprising: a first power source that applies a generation voltage; and a second power source that applies a voltage that controls corona ion generation to a third electrode. (2) The first and second electrodes face each other in a line, and the third electrode is composed of a plurality of electrodes arranged to intersect with the second electrode. Corona ion generator. (3) The corona ion generator according to claim 2, further comprising an accelerating electrode consisting of a plurality of electrodes penetrating the first and second electrode sides.