JPS5914754B2 - AC corona discharge device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alternating current corona discharge device, and more particularly to an alternating current corona discharge device that removes static electricity from the surface of a charged member.

Conventionally, various AC corona static eliminators have been used to eliminate static from photoreceptors, etc. of electrophotographic devices.

One of the special characteristics of an AC corona static eliminator used in an electrophotographic apparatus is that it is extremely important that the potential of the object to be neutralized after static elimination takes a predetermined value and is stable. The static elimination potential depends on various conditions of the AC corona, but the main causes of its instability are input fluctuations of the AC corona power supply and temperature and humidity fluctuations of corona discharge. However, in order to correct this, control of the input voltage, control of the ratio of ten components to one component of the AC high voltage waveform, etc. are considered.

Control of the high voltage waveform can be realized, for example, with a circuit as shown in Figure 1, but since various elements, namely diodes D1 and D2, and variable resistance volumes VR0 and VR2, are inserted into the high voltage side 2, insulation measures are difficult. Also, adjusting the volume from outside is dangerous. In addition, there was a risk that the volume and other components would be burnt if the high voltage side was short-circuited with the ground side. In the figure, 1 is an input winding, 3 is a corona discharger, and 4 is a counter electrode. The present invention has been made in view of the above points, and relates to a novel and excellent AC static eliminator.

The present invention provides an alternating current corona discharge device for neutralizing the surface of a charged member, comprising a corona discharge means, a series circuit of an input winding, an output winding, a rectifier, and a load resistor, the series circuit being connected between the output winding terminals. It is characterized by comprising an AC corona high voltage power supply in which circuits are connected in parallel and one terminal of the output winding is connected to the corona discharge means.

Hereinafter, details of the present invention will be explained using specific examples with reference to the drawings.

FIG. 2 shows a specific example of a device according to the present invention, where 1 is an input winding of a high-voltage power supply, 8 is a high-voltage output winding, 9 is a rectifier, 10 is a high-voltage resistor, and 11 is a variable resistor.

12 is an AC corona static eliminator.

The polarity of the rectifier is selected as required. By doing this, the ten components are the sum of the corona discharge current and the current flowing through the insertion circuit, one component is only the corona component and there are many ten current components, and the voltage drop of the ten voltages is large.

For this reason, the corona current has fewer ten components and more one component. By changing the resistance 11, the static elimination potential can be adjusted. Example 1 When the photoreceptor 5 charged to +1200V was subjected to AC corona charge removal of 6V using the circuit configuration shown in FIG. 3a, -20V was applied.
The charge was removed to 0V.

In contrast, the circuit configuration shown in FIG. 3, that is, the rectifier 9
By inserting a resistor of 10 MΩ and 10 MΩ in series, the similarly charged photoreceptor 5 was able to be neutralized to -30V.

Example 2 When the photoreceptor 5 charged to +1200V was subjected to AC corona charge removal of 5KV using the circuit configuration shown in FIG. 4A, the relationship between the charge removal potential and the environmental temperature was as shown by the dotted line in FIG.

That is, although a sufficient static elimination effect can be obtained when the humidity is low, it becomes difficult to obtain this effect when the humidity is high. The variability is approximately 400V. On the other hand, the circuit configuration shown in FIG.
When inserted in series, the solid line in Figure 5 shows that the surface potential changes due to humidity from about 400V to about 50V.
Stable within.

The humidity sensitive resistor used at this time was approximately 106Ω at 90%RH, 6
It was 107Ω at 0%RH and 109Ω at 30%RH. As described above, if the electrophotographic imaging process is performed using a high-voltage AC power source consisting of a series circuit of a manual winding, an output winding, a rectifier connected between the output terminals, and a resistor, corona discharge with desired characteristics can be achieved. Therefore, a sharp image without fog can be obtained.

In addition to the above-mentioned advantages, the present invention allows the corona characteristics to be freely controlled by adding a variable resistor to the front insertion circuit, and the polyurethane can be adjusted on the ground side, making insulation processing easy.

Furthermore, there is no risk of the element being burnt due to a short circuit on the high voltage side. Furthermore, if a humidity-sensitive resistor is used instead of a variable resistor, AC corona static elimination can be performed stably against humidity.

The principle of the present invention, including these modifications, is to control the load current to the output winding separately for the positive component and the single component, and to lower the voltage of one of them than the other to control static elimination of AC corona. That is.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of a conventional AC corona static eliminator, Fig. 2 is an explanatory diagram of a concrete example AC corona static eliminator based on the present invention, and Fig. 3a is an explanatory diagram of a comparative example device in Example 1. FIG. 3b is an explanatory diagram of the device based on Example 1 of the present invention, FIG. 4a is an explanatory diagram of the comparative example device in Example 2, and FIG. FIG. 5 is an explanatory diagram showing the static elimination effect with respect to changes in humidity. In the figure, 1, 7; primary winding of high voltage power supply; 2, 8; secondary winding of high voltage power supply; 3, 12; corona discharger; 4; counter electrode;
5; Photoreceptor.

Claims (1)

[Scope of Claims] 1. An AC corona discharge device for neutralizing the surface of a charged member, comprising: a corona discharge means; a series circuit of an input winding, an output winding, a rectifier, and a load resistor; an AC corona high-voltage power supply in which the series circuit is connected in parallel to the AC corona high-voltage power source, and one terminal of the output winding is connected to the corona discharge means.