JPH0518761Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a charging discharge device used in electrophotographic copying machines and the like.

2. Description of the Related Art As a discharge device for charging a charge receptor, for example, a photoreceptor in an electrophotographic copying machine, a corotron discharge device is generally known in which a high voltage current is passed through a corotron discharge thin wire to cause corona discharge.

This corotron discharge device is prone to breakage of the thin corotron discharge wire, which is not very desirable in terms of maintenance and inspection.

Therefore, the present applicant previously applied for a discharge device in which a plate-shaped electrode 2 is disposed facing a charge receptor 1 as shown in FIG. 3, and the plate-shaped electrode 2 is connected to a power source 3. did.

Note that the plate-shaped electrode 2 has a plate-like shape with the back electrode 4 and the discharge electrode 5, and the discharge electrode 5 has a volume resistance of 10 ⁶
~10 ¹³ Ω·cm and a surface resistance of 10 ⁶ Ω/port or more, so that the charge receptor 1 can be charged efficiently.

Problems to be Solved by the Invention After conducting various experiments and research on the discharge device shown in FIG. It has been found that stable discharge can be obtained by maintaining the temperature.

However, when the charge receptor 1 was actually charged by setting the gap between the charge receptor 1 and the plate electrode 2 to a value of 500μ or less, the difference between the two ends of the plate electrode 2 in the longitudinal direction was The discharge current in the central portion increased, and accordingly, the amount of charge in the central portion also increased compared to both ends of the charge receptor 1, making it impossible to charge the charge receptor 1 uniformly.

When we investigated the reason for this, we found that an electrostatic attraction force is generated between the charge receptor 1 and the plate-shaped electrode 2, so that the plate-shaped electrode 2 is bent in the longitudinal direction due to the electrostatic attraction force, and the air in the center is It was found that this is because the sky 〓 at both ends becomes smaller than the sky 〓 at both ends.

Therefore, the present invention makes it possible to make the space between the charge receptor and the plate electrode uniform in the longitudinal direction by preventing the plate electrode from being bent in the longitudinal direction, and thereby to charge the charge receptor uniformly. The purpose of the present invention is to provide a discharge device that has the following characteristics.

Means and operation for solving the problem A plate-shaped electrode 2 is provided which faces the charge receptor 1 through a small space and charges the charge receptor 1 by discharging it by applying a desired voltage. In the equipped discharge device, the plate-shaped electrode 2 is formed into a long plate-shaped body having a predetermined thickness, width, and length by the back electrode 4 and the discharge electrode 5, and the width direction at both longitudinal ends of the discharge electrode 5 is A pair of spacer members 6, 6 made of a material with a dynamic friction coefficient of 0.5 or less are provided on one side, and a deflection prevention member made of a material with a dynamic friction coefficient of 0.5 or less is provided on the same side as the spacer member 6 in the width direction of the discharge electrode 5. The members 8 are provided continuously in the longitudinal direction, and the pair of spacer members 6, 6 and the deflection preventing member 8 are brought into contact with the charge receptor 1, and both longitudinal ends of the plate-shaped electrodes 2 are pushed by springs 7 to form a left and right pair. A discharge device in which spacer members 6, 6 are pressed against a charge receptor 1.

As a result, the distance between the charge receptor 1 and the plate-shaped electrode 2 can be regulated by the pair of left and right spacer members 6, 6, and one side of the plate-shaped electrode 2 in the width direction can be extended in the longitudinal direction by electrostatic attraction. Deflection prevention member 8
In addition, the plate-like electrode 2 has a spacer member 6 and a deflection prevention member 8 on one side in the width direction, and the charge receptor 1
Since a void is formed between the other side in the width direction and the charge receptor 1, the other side of the plate electrode 2 in the width direction is displaced to the charge receptor 1 due to the electrostatic adsorption force acting on the void. However, since the plate electrode 2 is pressed against the charge receptor 1 by a pair of left and right springs 7, it will not be displaced.

Further, the spacer member 6 and the deflection prevention member 8 rub against the surface of the charge receptor 1 with a predetermined pressure, but since they are made of a material with good lubricity and a coefficient of dynamic friction of 0.5 or less, friction is prevented. be able to.

Example The plate-shaped electrode 2 becomes a long plate-shaped body having a predetermined thickness, width, and length by the back electrode 4 and the discharge electrode 5, and the back electrode 4 and the discharge electrode 5 are bonded with a conductive adhesive. The back electrode 4 is connected to the power source 3 and serves as a power supply electrode.

A pair of spacer members 6, 6 are provided on one side in the width direction at both ends of the discharge electrode 5 in the longitudinal direction. The space between the charge receptor 1 and the plate-like electrode 2 is set to a predetermined value, for example, 500μ or less, and the spacer is in pressure contact with the surface, and the space between the pair of spacer members 6, 6 is set to a predetermined value, for example, a value of 500μ or less. A deflection prevention member 8 having the same width and thickness as the spacer member 6 is provided on the discharge electrode 5, and the other side in the width direction of the discharge electrode 5 faces the charge receptor 1, and the charge receptor 1 is arranged in the direction of the arrow. As shown, the discharge electrode 5 is arranged to advance from one side in the width direction to the other side.

When a DC voltage of a desired polarity is applied between the back electrode 4 and the charge receptor 1 by the power supply 3 and the charge receptor 1 is moved in the direction of the arrow, the voltage between the discharge electrode 5 and the charge receptor 1 is Voltage is applied to the sky,
When the voltage reaches the discharge start voltage determined by the air distance, discharge starts and the charge receptor 1 is charged.

Here, the voltage applied between the discharge electrode 5 and the charge receptor 1 is V _A , and the discharge starting voltage with respect to the air distance between the discharge electrode 5 and the charge receptor 1 at this time is V _TH .
When the discharge current is i and the resistance value of the discharge electrode 5 is R, the following formula holds true.

V _A = V _TH + iR ... (1) Also, according to Patsien's law, the discharge starting voltage V _TH decreases as the air distance decreases, so according to equation (1), the discharge current increases at this time, but the air distance decreases. 〓If the variation in distance is within ±50 μm, it will not cause any practical problems.

Further, the deflection of the plate electrode 2 in the longitudinal direction due to the electrostatic attraction force is prevented by the deflection preventing member 8, so that the air can be maintained uniformly over the longitudinal direction, and the charge receptor 1 can be charged uniformly.

Note that one widthwise side of the plate-shaped electrode 2 is in contact with the charge receptor 1 through the spacer member 6 and the deflection prevention member 8, and a space is formed between the other widthwise side and the charge receptor 1. Due to the electrostatic adsorption force acting on the air, the other side of the plate electrode 2 in the width direction is displaced to the charge receptor 1, and in order to prevent the air distance from changing by more than 50 μm, a spring 7 is used to hold the plate electrode 2. is imposing.

For this purpose, the spacer member 6 and the deflection prevention member 8
Since these are rubbed against the surface of the charge receptor 1 with a predetermined pressure, it is desirable to make them of a material with good lubricity in order to prevent wear.

For example, the materials for the spacer member 6 and the deflection prevention member 8 should preferably have a dynamic friction coefficient of 0.5 or less.
In this case, it has been confirmed through experiments that whether the material of the charge receptor 1 is a metal semiconductor or an organic semiconductor, it can withstand repeated use for more than 200,000 cycles without causing problems due to wear.

Examples of materials having a dynamic friction coefficient of 0.5 or less include urethane rubber, silicone resin, or polypropylene resin filled with fluorine resin fine powder or glassy carbon fine powder.

In addition, as shown in FIG. 2, the spacer member 6 and the deflection prevention member 8 may be integrated.

Effects of the invention: The distance between the charge receptor 1 and the plate electrode 2 can be regulated by the pair of left and right spacer members 6, 6, and one side of the plate electrode 2 in the width direction is fixed in the longitudinal direction by electrostatic attraction. The plate-like electrode 2 can be prevented from being bent by the deflection prevention member 8, and one side in the width direction of the plate electrode 2 is in contact with the charge receptor 1 by the spacer member 6 and the deflection prevention member 8, and the other side in the width direction is in contact with the charge receptor 1. Since a space is formed in between, the other side of the plate-shaped electrode 2 in the width direction tends to be displaced to the charge receptor 1 due to the electrostatic adsorption force acting on the space, but the pair of left and right springs 7 prevent the plate-shaped electrode from moving. Since the charge receptor 2 is pressed against the charge receptor 1, it will not be displaced.

Therefore, the plate-shaped electrode 2 can be reliably prevented from being bent in the longitudinal direction due to the electrostatic attraction force generated between the plate-shaped electrode 2 and the charge receptor 1, and the air space between them can be prevented. Since the gap can be maintained constant over the longitudinal direction, the charge receptor 1 can be charged uniformly.

Further, the spacer member 6 and the deflection prevention member 8 rub against the surface of the charge receptor 1 with a predetermined pressure, but since they are made of a material with good lubricity and a coefficient of dynamic friction of 0.5 or less, friction is prevented. be able to.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the first embodiment of the present invention, FIG. 2 is a perspective view of the second embodiment, and FIG. 3 is an explanatory diagram of the discharge device previously filed. 1 is a charge receptor, 2 is a plate electrode.

Claims (1)

[Claims for Utility Model Registration] Equipped with a plate-shaped electrode 2 that faces the charge receptor 1 through a small space and charges the charge receptor 1 by discharging by applying a desired voltage. In the discharge device, the plate-shaped electrode 2 is formed into a long plate-shaped body having a predetermined thickness, width, and length by a back electrode 4 and a discharge electrode 5, and one side in the width direction at both longitudinal ends of the discharge electrode 5. A pair of spacer members 6, 6 made of a material having a dynamic friction coefficient of 0.5 or less are provided in the spacer member 6 in the width direction of the discharge electrode 5.
A deflection prevention member 8 made of a material having a dynamic friction coefficient of 0.5 or less is provided continuously in the longitudinal direction on the same side as the plate, and the pair of spacer members 6 and the deflection prevention member 8 are in contact with the charge receptor 1, and the plate A discharge device in which a pair of left and right spacer members 6, 6 are pressed against a charge receptor 1 by pushing both longitudinal ends of a shaped electrode 2 with a spring 7.