JPS59224864A - Corona discharger - Google Patents

Abstract

PURPOSE:To prevent dust from sticking a corona discharge electrode efficiently and to improve its durability by vibrating a vibrating piece only during a discharge period, and vibrating the corona discharge electrode. CONSTITUTION:If a thin wire 23 for discharge is vibrated all the time, vibration strain is applied for a long time, so the metallic fatigue of the thin wire 23 for discharge is accelerated, and the wire deteriorates or is broken in its early stage, so that the durability deteriorates. For the purpose, a driving signal R1 and a feed signal R2 are supplied by a control mechanism 11 to an oscillator 26 which propagates vibration to the vibrator 24 and a high voltage source 27 at the same time to cause vibration by the vibrating piece 25 while a high voltage is applied to the thin wire 23. Consequently, the vibration is obtained only during a discharge period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a corona discharge device used as a device for charging a photoreceptor of a copying machine.

[Prior art] A known discharge device is one in which a thin discharge wire serving as a corona discharge electrode is stretched within a shield, and a high voltage is applied to this circular discharge wire to cause corona discharge. .

In such a corona discharge device, a strong electric field is formed on the surface of the thin discharge wire, so that dust such as toner in the copying machine is likely to adhere to it due to electrostatic force.

When dust adheres to the fine discharge wire in this way, the discharge performance and charging performance tend to deteriorate, which is not preferable for a corona discharge device.

OBJECTS OF THE INVENTION It is an object of the present invention to efficiently prevent dust from adhering to discharge electrodes and to improve the durability of corona discharge electrodes.

Structure of the Invention A vibrating piece is vibrated only during the discharge period of the discharge electrode to impart vibration to the corona discharge electrode.

Embodiment FIG. 1 is a schematic explanatory diagram of a copying machine, in which a photoreceptor 2 is provided in the main body of the copying machine, and chargers 3 and n are arranged around the photoreceptor 2.
A light slit 4, a developing device 5, a transfer device 6, a cleaner 7, etc. are arranged in this order, and an exposure optical system 9 irradiates the original image on the platen ε onto the photoreceptor 2 through the exposure slit 4. When the copying start button 10 is turned on, the control mechanism 11 controls the operation of each device according to a predetermined copying process, and the self-charging device 3 and the transfer device 6 function as the corona discharge device according to the present invention. It's contradictory.

Is the charger 3 21? ￥2 As shown in the figure, shield 2
A pair of insulating blocks 21 and 22 are provided at the shield 20, and a thin discharge wire 23 serving as a corona discharge electrode is stretched across the pair of one corner blocks 2+ and 2.2. It has a structure in which the vibrating piece 25 that is vibrated is brought into contact with the thin discharge wire 23 at f2.

As a result, the thin discharge wire 23 is vibrated, and the surface acceleration of the thin discharge wire created by the constant pressure wave is used to blow away dust, and the vibration causes the B ground to adhere to the thin discharge wire. can be prevented from adhering to the surface.

However, if constant vibration is applied to the thin discharge wire 23, vibrational strain will be applied to the thin discharge wire 23 for a long time, which will accelerate metal fatigue of the thin discharge wire 123 and cause early deterioration or breakage. This is not preferable because the durability deteriorates.

Therefore, the inventor conducted various experiments and found the following.

It has been found that the amount of dust adhering to the surface of the thin discharge wire 23 is smaller when the vibration 41 is applied at the same time as the discharge than when the vibration is applied after the discharge ends.

This can be thought of as follows.

The reason why dust adheres to the thin discharge wire is that the dust comes into close contact with the thin discharge wire due to electrostatic attraction force called gradient force and Coulomb force. Once dust adheres to the thin discharge wire, the electrostatic attraction force In addition to this, energy mainly from chemical potential such as intermolecular force and adsorption force due to water is added, so the adhesion of the dust bowl becomes even stronger.

Therefore, if vibration is not applied during discharge but only during the period when the discharge body is stopped, the dust ′l, A, which has once adhered will be blown away, so many choices H=+ and energy will be required. do.

On the other hand, if vibration is applied at the same time as discharge, the thin discharge wire vibrates and vibrates when the dust tries to approach the discharge port wire, so the probability of contact decreases and it sticks. Even when probed, it takes time for the surface tension of the water to become dominant, and by applying vibrations at a sufficiently faster frequency than that, the attached dust can be blown away.

From this, it can be considered that dust adhesion can be more effectively prevented by applying vibration during discharge.

Therefore, as shown in FIG. 2, the drive signal R and the power supply signal R3 are simultaneously applied from the control mechanism 11 to the oscillator 26 that propagates vibrations to the vibrator 24 and the high-voltage power supply 27. A high voltage was applied to the 1J13 wire 23, and the vibrating piece 25 gave vibration while discharging.

This allows vibration to be applied only during the discharge period.

Next, a specific example will be explained.

conditions,. , the length of the thin discharge wire 23 is 3F34mm, and the wire diameter is g.
9μ, the frequency of the vibrating piece 25 is 40Kz, the entire device is placed in a sealed box, and the toner for the duplicator is swept inside the box.
7 and dispersed.

Under the above conditions, the amount of toner attached to the thin discharge wire 23 was measured 10 times when vibration was applied simultaneously, when vibration was applied after discharge stopped, and when no vibration was applied. , and the average values are shown in the table in FIG.

The amount of toner was measured using a microscope.

The results shown in FIG. 3 also show that applying vibration at the same time as discharge is more effective in preventing dust from adhering to the thin discharge wire 23.

Furthermore, since vibration is applied only during the discharge period, metal fatigue of the thin discharge wire 23 is reduced and durability is improved.

Note that the above also applies to the case where a sawtooth electrode is used as the corona discharge electrode.

Effects of the Invention It is possible to efficiently prevent dust from adhering to the corona discharge I'H electrode, and to improve the durability of the corona discharge cup.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a schematic explanatory diagram of a multi-gear machine, Fig. 2 is a perspective view of a transfer device, and Fig. 3 is a toner adhesion V.
It is a blue diagram showing 1. 20 is #)”, 231d=I mouth f discharge?ff,
Pole, 25 vibrating pieces. Applicant Fuji Xerox Co., Ltd. Agent Patent Attorney Masaaki Yonehara Patent Attorney Tadashi Hamamoto (7) at. 3rd

Claims (1)

[Claims] The vibrating piece 2 is attached to the corona discharge electrode 23 provided on the shield 20.
5. A corona discharge device characterized in that the vibrating piece 25 is vibrated only during the discharge period of the corona discharge electrode 23.