JPH0243575A - Corona discharging device - Google Patents

Abstract

PURPOSE:To prevent the vibration of a discharge electrode wire by detecting a discharging current corresponding to the vibration and performing control in the way that the discharging current is roughly stabilized or the current is increased/decreased in a range of prescribed values when the current is increased. CONSTITUTION:The discharge electrode wire 4 and its corresponding electrode 3 are closely arranged with a space (a) between them, and the discharging current I is largely changed by the vibration. Then the discharging current I is detected by a detecting resistor R1 and fed back to a constant current circuit for low-volage driving operation 7 in the primary side of a booster transformer T. Then, the I is controlled to be kept constant and the vibration is suppressed. Besides, even if vibration damping action is performed by the feed back control of the discharging current I, an electrifying current Ic is controlled to be a constant current by another independent power source 2 through the use of a detecting resistor R2, and electrifying function is not damaged. Thus, the vibration of the discharge electrode wire 4 is controlled by electrical control.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a corona discharge device used in a printer 1, a copying machine, as well as an air purifier and an ion generator. The present invention relates to a catenary type corona discharge device in which a catenary discharge electrode wire is used as a catenary wire.

[Conventional technology]

When a high voltage is applied to a corona discharge device in which a discharge electrode wire with a diameter of several tens of micrometers is connected, the discharge electrode wire may vibrate. This means that the thinner the wire diameter is in order to suppress the amount of ozone generated, and the closer the corresponding electrode plates are brought together in order to downsize.
Furthermore, the stronger the discharge is in response to high-speed charging, and the longer the overhead wire is, the more likely vibrations will occur. There is also a problem in that when the discharge electrode wire vibrates, uneven charging occurs.

To this end, conventional vibration prevention mechanisms have been developed, including a vibration prevention mechanism that applies pressure to the discharge electrode wire using the weight of an insulating block, a vibration prevention mechanism that includes a member that comes into contact with the discharge electrode wire and absorbs vibration energy, and a vibration prevention mechanism that applies tension to the discharge electrode wire. A vibration prevention mechanism is known in which a separate object is provided on a spring to prevent vibration.

[Problem to be solved by the invention]

In all of the above-mentioned conventional techniques, vibration of the discharge electrode wire is mechanically prevented, and installation adjustment during manufacturing is difficult, and reliability is also uncertain. Furthermore, since it is installed near the overhead wire support, the overhead wire support portion becomes large. Further, there are problems such as an undesirable mechanism that imposes restrictions on various wire tensioning means.

An object of the present invention is to provide a corona discharge device that eliminates the drawbacks of the above-mentioned prior art, achieves miniaturization, high-speed charging, reduces the amount of ozone generated, and can prevent vibration of the discharge electrode wire. be.

[Means to solve the problem]

To achieve the above object, the present invention provides a corona discharge device in which a discharge electrode wire is connected, and a detecting means capable of detecting a discharge current corresponding to vibrations, and a detection means capable of detecting a discharge current corresponding to vibration, and a method for controlling the discharge current to be kept approximately constant when the discharge current increases. The present invention is characterized by comprising a control means for controlling the value to fall within a predetermined range.

[Effect]

In the present invention, the corona discharge device is configured to be able to detect a discharge current corresponding to vibrations, and when the current increases, it works to reduce the discharge voltage and keep the discharge current approximately constant or increase or decrease between predetermined values. Control as follows. Thereby, vibration of the discharge electrode wire can be prevented.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIGS. 1, 2, and 3 are circuit diagrams of corona discharge devices according to different embodiments, and FIGS. 4 and 5 are AC voltage waveform diagrams of FIG. 3.

FIG. 1 shows a DC corona discharge device, in which two power sources are prepared: a corona discharge power source 1 and a charging power source 2 for charging an object to be charged.

Separating the two functions and adjusting them independently is necessary for a design that takes into account reduction in ozone generation, uniformity of charging, etc. In the corona discharge type #I, 7 is a low voltage drive constant current circuit, T is a transformer, 8 is a rectifier circuit consisting of a capacitor and a diode, and R is a detection resistor for detecting the discharge current I. In addition, the charging power source 2 includes a low voltage drive constant current circuit 7,
In addition to the transformer T and the rectifier circuit 8, a detection resistor R2 for detecting the charging current IC is provided. Reference numeral 3 designates a plate-shaped corresponding electrode that uniformly generates a corona discharge, 4 a discharge electrode wire, 5 a discharger that collectively includes these, and 6 a photoreceptor that is a charged member. Further, a is the distance between the corresponding electrode 3 and the discharge electrode line 4, and b is the distance between the discharge electrode line 4 and the photoreceptor 6.

The distance a between the discharge electrode wire 4 and the corresponding electrode 3 is several hundred μm, and the two are arranged close to each other, but in this case, the discharge current l due to vibration.
undergoes major changes. This is considered to be because the impedance between the discharge electrode wire 4 and the dielectric surface is the main load in the discharge circuit. The current increases when the discharge electrode wire 4 approaches the dielectric (due to vibration), and decreases when it moves away from the dielectric.

Furthermore, if the interval a is made small and b is made large, the change in the discharge current T due to vibration becomes large and becomes easier to detect.

Then, the discharge current (2) is detected by a detection resistor R5, and is fed back to the low voltage drive constant current circuit 7 on the primary side of the step-up transformer T, thereby controlling the discharge current (2) to be kept constant. Preferably, when the interval a becomes small due to vibration, excessive control to make the current value smaller than the initial value may be more effective in actively suppressing the vibration.

The force with which the discharge electrode '1IA4 is drawn by the corresponding electrode 3 depends on the discharge current r, which varies when the discharge voltage is constant and the interval a changes, and is basically approximately proportional to 2. When the discharge electrode wire 4 approaches the corresponding electrode 3, the attraction to the discharge electrode wire 4 becomes stronger, and when the discharge electrode wire 4 moves away from it, it weakens, making it easier to generate vibrations. It can be seen that even if the discharge electrode wire 4 approaches or moves away, vibrations are less likely to occur if l is kept at a constant current, and excessive control is more effective in preventing vibrations.

Even if an anti-vibration effect is performed through feedback control of the discharge current I, the charging function is not compromised because the charging current Ic is controlled at a constant current by a detection resistor R2 and another independent power source. Further, this vibration frequency is determined by the tensile strength of the wire, the length of the overhead wire, etc., and is several hundred I(z) in this embodiment, and it is natural that the response speed of the control is also restricted to this frequency.

FIG. 2 shows an embodiment in which a resistor R0 is connected in series with the discharger 5 in the discharge circuit instead of detecting and controlling the discharge current, and Ro will be referred to as an anti-vibration resistor. When the discharge current (2) increases or decreases due to the vibration of the discharge electrode wire 4, the voltage drop across the anti-vibration resistor R6 changes with an instantaneous response, which functions to suppress fluctuations in the discharge current I, resulting in an anti-vibration effect. Although it does not have an active anti-vibration effect, this anti-vibration resistance R0 has an amazing anti-vibration effect near the boundary conditions of vibration generation.In addition, in this embodiment, the charging current I is controlled at a constant current, and the corona A single power source is used that also serves as a power source for generation.

FIG. 3 shows a modification of the embodiment shown in FIG. 2, and the corresponding electrode 3 has a structure in which an electrode plate 3b is covered with a dielectric material (1,6t glass) 3a. Furthermore, the corona discharge is an alternating current component, and the charging function uses the direct current voltage obtained by rectifying the alternating current to create a power source. The charging current I is controlled to be a constant current.

As mentioned above, the interval a is small (and the discharge current I changes greatly due to vibration, but by inserting only the vibration isolation resistor R6 of tens to hundreds of ohms), the vibration can be sufficiently stopped.

Note that C2 is a noise cutting capacitor.

The waveform of the AC voltage V mc of the small capacity power supply shown in FIG. 3 is shown in FIGS. 4 and 5.

Figure 4 shows a sine wave with a frequency fr of 1 to 10 KHz.
If the voltage is set to a certain level, the IC and transistor of the low voltage drive constant current circuit 7 will control the entire cycle, and the transformer T will also be larger than that for pulse transmission. Figure 5 shows an internal reduction of 1/f r. A corona is generated for a period of only seconds, and the remaining period is allowed to freely oscillate (at a frequency determined by the -order and secondary discharge circuits).

Therefore, for a short period of approximately 1°, the low voltage drive constant current circuit 7
Since to has a pulse waveform and is a harmonic, there is an advantage that the transformer T can be small.

When using a waveform as shown in FIG. 5, inserting the vibration isolation resistor R8 results in substantially lowering the secondary side output voltage as shown in the waveform shown by the broken line in FIG. In this case, the anti-vibration resistance R6
It was also found that bypassing, which connects a capacitor Co in parallel with the voltage drop to reduce the voltage drop of the pulse, is effective. Although only the anti-vibration resistor R0 is sufficient, in the case of a pulse waveform, it would have been better to provide a bypass of C0.

In the embodiment shown in FIG. 1, the detection resistor R2 is the means for detecting the discharge current I, and the low voltage drive constant current circuit 7
It is a means of control. Furthermore, in the embodiments shown in FIGS. 2 and 3, the anti-vibration resistor R0 serves both as a detection means and a control means.

〔Effect of the invention〕

The present invention is as described above, and since the vibration of the discharge electrode wire is prevented by electric control f'B, a highly reliable corona discharge device can be provided.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are circuit diagrams of corona discharge devices according to different embodiments, and FIGS. 4 and 5 are AC voltage waveform diagrams of FIG. 3. 3... Corresponding electrode, 4... Discharge electrode wire, 7... Low voltage drive constant current circuit, R1... Detection resistor, Ro... Anti-vibration resistor. Figure 1 Figure 2

Claims (1)

[Claims] In a corona discharge device in which a discharge electrode wire is connected, a detection means capable of detecting a discharge current corresponding to vibration, and a control that controls the discharge current to be approximately constant or within a predetermined value range when the discharge current increases. A corona discharge device characterized by comprising means.