JP2833029B2 - Corona discharge device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a corona discharge device used in an electrophotographic apparatus.

2. Description of the Related Art Conventionally, a corona discharge device used for separation and charge removal of an electrophotograph has a configuration as shown in FIG. In FIG.
1 is a photoreceptor, 2 is a corotron, 3 is an output winding of an AC high-voltage power supply, 4 is a primary winding, 5 is an AC input source, and 6 is a DC power supply. In the operation of FIG. 7, a DC power supply 6 is connected in series to an AC high-voltage output generated by the output winding 3, and a voltage in which a DC voltage is superimposed on an AC voltage is applied to the wire of the corotron 2, and A current in which a direct current is superimposed on an alternating current flows through the stabilizer 2 (hereinafter referred to as a stabilizer) and the photosensitive member 1.

FIG. 8 is a diagram for applying two corotrons 2 to the corotron 2 for separation and static elimination, wherein 1 is a photoreceptor, 2 is a corotron, 3, 3 are output windings of an AC high-voltage power supply,
4 is a primary winding, 5 is an AC input source, and 6 and 6 are DC power supplies. The operation is the same as that of FIG. 7, except that the output windings 3, 3 and the DC power supply
You need two 6,6.

Problems to be Solved by the Invention In such a conventional configuration, an AC power supply and a DC power supply are required to superimpose a DC current on an AC / DC. This DC power supply includes a control circuit, a transformer, a rectifier circuit, a detection circuit, and the like. In such a configuration, the circuit becomes complicated, the power supply becomes large, and the cost increases.

When two or more high-voltage outputs are required, for example,
When a high voltage is applied for separation and static elimination, independent DC power supplies 6, 6 and two output windings 3, 3 are required as shown in FIG. For this reason, the step-up transformer of the AC high-voltage power supply 5 becomes large, and two DC power supplies 6, 6 are required, so that the size and cost are further increased as compared with the case of one output.

An object of the present invention is to provide an inexpensive and small-sized corona discharge device that eliminates the above-mentioned conventional drawbacks and does not use a DC power supply.

Means for Solving the Problems In order to solve this problem, the present invention provides an output winding and a capacitor of an AC high-voltage power supply between a wire of a corona discharge corotron and a ground, which are arranged to face a grounded photoconductor. Are connected in series, and a diode and a resistor or a diode and a variable impedance element connected in series are connected in parallel to a series circuit of an output winding and a capacitor.

Operation The operation of this technical means is as follows.

That is, by connecting a capacitor in series with the output winding of the AC high-voltage power supply, no DC current flows through the output winding of the AC high-voltage power supply. In addition, a diode and a resistor are connected in series between the output winding and ground, so that a DC current flows.However, since a capacitor is connected in series to the output winding, it is connected to the output winding. No DC current flows. Here, a current which is rectified by the diode and flows to the ground via the resistor is generated, so that a current equal to this current but in the opposite direction flows to the corotron.

With the above configuration, a current obtained by superimposing a DC current on an AC current can flow through the corotron.

Embodiment FIG. 1 shows an embodiment of the present invention. In FIG.
11 is a grounded photoreceptor, 12 is a corotron, 13 is an output winding of an AC high-voltage power supply, 14 is also a primary winding, 15 is an AC input source, and 16 is connected between one end of the output winding 13 and ground. Capacitor, 17 is a diode connected between the other end of output winding 13 and ground, 18 is a resistor connected in series with diode 17, 21 is a step-up transformer formed by primary winding 14 and output winding 13. It is.

The operation of FIG. 1 is as follows. The AC high voltage generated in the output winding 13 is applied to the wire of the corotron 12,
A current flows through the photoconductor 11 and the stabilizer. Since this capacitor is connected in series with the output winding 13, no DC current flows through the output winding 13. However, since a positive current flows through the diode 17 and the resistor 18, a direct current having the same value as the average value of the current and having the opposite direction flows through the photoconductor 1s and the stabilizer.

FIG. 2 is an equivalent circuit of FIG. ₁ , where i ₁ and i ₂ are currents flowing from the wires of the corotron 12 to the stabilizer and the photoconductor 11. Here, assuming that the diode 17 and the resistor 18 are not provided, R ₁ <R ₂ from the characteristics of the corona discharge, and the current becomes i ₁
> I _{2 and the} negative current is larger than the positive current,
Since the capacitor 16 is connected in series to the output winding 13, i ₁ = i ₂ , and the capacitor 16 is in a state where a positive DC voltage is applied.

Turning now to connect a diode 17 and a resistor 18, a current flows i ₃ polarity of the AC high voltage power supply output winding 13 via a positive diode 17 and resistor 18 when. Here, since the capacitor 16 is connected in series to the output winding 13, the relationship between i ₁ , i ₂ , and i ₃ is represented by the following equation.

i ₁ −i ₂ = i ₃ Equation (1) That is, it can be seen that the DC current flowing through the corotron 12 and the photoconductor 11 is equal to the current i ₃ flowing through the diode 17 and the resistor 18.

FIG. 3 shows the characteristics of FIG. 1 measured and represented in a graph. As a condition, the output voltage of the output winding 13 is 5.0K
V _rms sine wave, resistance 18 is 100MΩ in graph of (a), (b)
The graph of is 50 MΩ. Although here occurs a little inclination to the graph, this is because the DC current i ₃ and the DC voltage applied to the capacitor 16 is changed to change a no little problem value. There is no problem even if a capacitor is connected in parallel with the resistor 18 as shown by the broken line in FIG. As described above, a DC constant current can be superimposed with a very simple circuit configuration.

4 to 6 show another embodiment of the present invention.

FIG. 4 shows an example in which a variable impedance element 19 is connected to vary the DC current, 11 is a photoconductor, 12 is a corotron, 13 is an output winding, 14 is a primary winding, and 15 is an AC input source. , 16 are capacitors, 17 is a diode, 18 is a resistor, and 19 is a variable impedance element such as a variable resistor. The operation of FIG. 4 is the same as that of FIG. 1, but the DC current can be arbitrarily adjusted by the variable impedance element 19.

FIG. 5 shows an embodiment in which an AC high voltage output is applied to two corotrons, 11 is a photoconductor, 12 is a corotron, 13 is an output winding, 14 is a primary winding, 15 is an AC input source, and 16 is an AC input source. A capacitor, 17 is a diode, and 18 is a resistor. The DC current of the two corotrons 12 in FIG. 5 flows in the same operation as in FIG. Further, since the capacitors 16 are connected in series to the respective outputs, the respective direct currents can be set independently without affecting.

FIG. 6 shows an embodiment in which the stabilizer of the corotron 12 is grounded via a capacitor. In FIG. 6, 11 is a photoconductor, 12 is a corotron, 13 is an output winding, 14 is a primary winding, 15
Is an AC input source, 16 is a capacitor, 17 is a diode, 18 is a resistor, and 20 is a bypass capacitor. The operation of FIG. 6 is as follows. Since the stabilizer is grounded via the bypass capacitor 20, no DC current flows through the stabilizer.
Since the other operations are the same as those in FIG. 5, the DC current flowing from the wire of the corotron 12 to the photoconductor 11 becomes a constant current.

Advantages of the Invention As described above, according to the present invention, (1) a DC constant current can be superimposed on an AC without using a DC power supply, and miniaturization and cost reduction can be achieved.

(2) When applying a high voltage to two or more corotrons, conventionally, two or more output windings are required, and in order to superimpose an independent DC constant current, a DC constant having the same number as the number of outputs is used. Although a current power supply was required, the present invention enables the use of one output winding, so that a DC constant current power supply is not required, and miniaturization and cost reduction can be achieved.

(3) Since the DC current flowing through the photoreceptor can be controlled independently, it can be used as a high-voltage power supply to be applied to a charging and transfer corotron, which is usually applied with a DC power supply.

(4) By reversing the connection direction of the diode,
The direction of the direct current can be changed, and the present invention can be used for an electrophotographic apparatus such as a printer in which the polarity of charging and transfer is reversed.

With the effects described above, the present invention has an extremely high industrial value.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of one embodiment of a corona discharge device of the present invention,
FIG. 2 is an equivalent circuit diagram of FIG. 1, FIG. 3 is a graph showing the characteristics of FIG. 1 measured and represented in a graph, and FIGS. 4, 5, and 6 are diagrams of another embodiment of the present invention. 7 and 8 are circuit diagrams of a conventional corona discharge device. 11 photoconductor, 12 corotron, 13 output winding, 14
…… Primary winding, 15… AC input source, 16 …… Capacitor,
17 …… Diode, 18 …… Resistance, 19 …… Variable resistance, 20…
… Bypass capacitor, 21 …… Step-up transformer.

Continuation of front page (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 15/02 G03G 15/14 G03G 15/16 H01T 19/00

Claims (4)

(57) [Claims] An output winding of an AC high-voltage power supply and a capacitor are connected in series between a wire of a corona discharge corotron arranged opposite to a grounded photoconductor and a ground, and a diode and a resistor or a diode are connected. And a variable impedance element connected in series to a series circuit of an output winding and a capacitor in parallel with a corona discharge device. 2. A photovoltaic device, comprising: a photoconductor;
A circuit in which a capacitor is connected in series between the high-voltage side of an output winding of an AC high-voltage power supply that takes out two or more AC high-voltage outputs from one output winding between a wire of at least one corona discharge corotron and ground; A corona discharge device in which a diode and a resistor or a circuit in which a diode and a variable impedance element are connected in series are connected in parallel. 3. The corona discharge device according to claim 1, wherein the stabilizer plate of the corona discharge corona discharge is grounded via a capacitor. 4. An electrophotographic apparatus using the corona discharge device according to any one of (1), (2) and (3).