JPH0453432B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to a corona discharge device that applies electric charge by corona discharge, and for example, a charging charger that charges a photoreceptor in an electrophotographic copying machine, and a toner image on a photoreceptor. The present invention relates to a corona discharge device such as a transfer charger that transfers a photoreceptor onto a copy paper, a separation charger that separates the copy paper after transfer from a photoreceptor, and a static elimination charger that removes static electricity from a photoreceptor.

Prior Art Generally, in a corona discharge device, a large amount of ozone is generated during discharge. It is known that this ozone not only deteriorates the photoreceptor of a copying machine, but also is harmful to the human body. For this reason, in Japanese Patent Application Laid-Open No. 56-154759, as shown in FIGS. 1 to 4, a heat generating member 5,
A corona discharge device has been proposed in which a plurality of heat generating members 5, 6, 8 are installed in tension, and the ozone generated in the vicinity of the corona electrode 1 is thermally decomposed by the heat generating members 5, 6, 8.

However, in the above device, the heat generating member 5,
Since the heat generation temperature of 6 and 8 is 200 DEG C. to 300 DEG C., the corona electrode 1 expands due to the heat, resulting in non-uniform discharge characteristics. Further, when the above device is used in an electrophotographic camera, the heat generating member 5,
There is a risk that the photoreceptor may deteriorate due to the heat generated by the devices 6 and 8, and further damage may occur in that the toner is fused to the device itself.

In order to solve many of the above problems, the heat generating member 5,
It is possible to suppress the amount of heat generated by 6.8. However, when the heat generation temperature is lowered, part of the ozone generated near the corona electrode 1 is transferred to the heat generation member 5,
Although some ozone is thermally decomposed by the ozone decomposition members 5, 6, and 8, some of them pass between the heat generating members 5, 6, and 8 without being decomposed, resulting in low ozone decomposition efficiency. Also,
In a corona discharge device that uses creeping discharge,
A back electrode formed of a plate-shaped metal plate, an insulating member covering one surface of the back electrode, and a thin wire fixed to the surface of the insulating member so as to face the back electrode through the insulating member. It has a shaped excitation electrode, and an alternating current voltage is applied between the back electrode and the excitation electrode to perform corona discharge.

However, when charging is performed by corona discharge in the above device, since the surface shape of the insulating member covering the back electrode is planar, the shape of the object to be charged is not planar, for example, drum-shaped. case,
Since the distance between the insulating member and the object to be charged cannot be made constant over the entire surface, there are areas where the distance between the two is wide, resulting in low charging efficiency.

Purpose The present invention has been made in view of the above points, and its purpose is to efficiently decompose the ozone generated, to prevent deterioration of the photoconductor, toner fusion, etc., and to stabilize the toner. An object of the present invention is to provide a corona discharge device capable of efficient corona discharge.

Summary In order to achieve the above object, a corona discharge device according to the present invention includes a back electrode formed of a metal plate, a heat-resistant insulating member that covers the entire surface of the back electrode, and a heat-resistant insulating member that covers the entire surface of the back electrode. a thin wire-shaped excitation electrode fixedly installed through the heat-resistant insulating member, a power supply for applying an alternating current voltage between the back electrode and the excitation electrode, and a heat-resistant insulating member on the other side of the back electrode. A corona discharge device is provided with a heating means fixed through an insulating member, wherein the surface of the heat-resistant insulating member facing the charged object has a shape corresponding to the shape of the charged object. shall be.

Embodiment Hereinafter, a corona discharge device applied to the present invention will be explained using FIGS. 5 and 6.

The corona discharge device 10 includes a back electrode 11 formed of a metal plate such as a copper plate, and a heater 12 as a heating means.
are integrally covered with a heat-resistant insulating member 13 made of ceramic, polyimide resin, etc., and a thin wire-shaped excitation electrode 14 is fixed on the outer surface thereof, facing a charging object 15 such as an electrophotographic photoreceptor. It will be arranged as follows. The heater 12 also includes a heater power source 16,
A high voltage AC power supply 17 is connected between the back electrode 11 and the excitation electrode 14, and a DC bias power supply 18 is connected between the excitation electrode 14 and the charging target section 15.

In the above configuration, the back electrode 11 and the excitation electrode 1
When a corona voltage is applied between the excitation electrode 14 and the excitation electrode 14 by the high voltage AC power supply 17, a corona discharge (creeping discharge) occurs in the vicinity of the excitation electrode 14, and positive and negative ions are generated. These ions are absorbed by the DC bias power supply 1
The object to be charged 15 can be charged to an arbitrary polarity and potential depending on the polarity of the bias applied by 8. For example, when charging the object 15 to be charged to a positive polarity, the excitation electrode 14 is used as a positive electrode, and when charging the object 15 to a negative polarity, the excitation electrode 14 is used as a negative electrode. Incidentally, by stopping the bias application by the DC bias power supply 18, it can also be used as a static elimination charger for performing AC corona discharge.

On the other hand, along with the application of the corona voltage, energization of the heater 12 by the heater power source 16 is also started, and the corona discharge device main body 10 is heated, and the heat-resistant insulating member 1
3 to the excitation electrode 14 and its vicinity from 30° to 100°.
Heat in the range of °C. This heating temperature is 30°
Although the temperature is as low as ~100° C., the ozone generated during corona discharge is efficiently decomposed because the excitation electrode 14 and its vicinity, which is the source of ozone, are heated. Moreover, the excitation electrode 14 to be heated is
Since the heating temperature is as low as 30° to 100°C, the discharge characteristics will not become non-uniform due to thermal expansion. Note that heating of the heater 12 may be started prior to application of the corona voltage.

Using the above corona discharge device, high voltage AC power supply 17
between the back electrode 11 and the excitation electrode 14.
When we investigated the ozone decomposition efficiency by varying the output of the heater power supply 16 under the application of a corona voltage of 7.5KV rms 10KHz, we found that if the temperature of the excitation electrode 14 is 50℃ or higher, more than 90% of the ozone generated is It was confirmed that it was disassembled.

Therefore, when the above corona discharge device is used in an electrophotographic copying machine, by setting the heating temperature by the heater to, for example, 50°C, most of the ozone generated during corona discharge is decomposed and the ozone is used for charging purposes. There is no thermal effect on the object 15, no expansion of the excitation electrode 14 and uneven discharge characteristics, and no fusion of toner.

7 and 8 show embodiments of the present invention,
Charging efficiency is improved by forming the corona discharge device main body 10 into a curved shape corresponding to the shape of the drum-shaped object 15 to be charged.

Effects As described above, the present invention includes a back electrode formed of a metal plate, a heat-resistant insulating member covering the entire surface of the back electrode, and the heat-resistant insulating member on one side of the back electrode. a thin wire-shaped excitation electrode fixedly installed through the excitation electrode, a power supply that applies an alternating voltage between the back electrode and the excitation electrode, and a power supply fixed to the other side of the back electrode via the heat-resistant insulating member. 1. A corona discharge device comprising a heating means, wherein the surface of the heat-resistant insulating member facing the charged object has a shape corresponding to the shape of the charged object. , since it heats the excitation electrode, which is the source of ozone generation, and its vicinity, there is a risk of thermal effects on the object to be charged, toner fusion,
Ozone generated during corona discharge can be efficiently decomposed at a low heating temperature that does not cause uniformity of corona discharge, and charging efficiency can be increased.

[Brief explanation of the drawing]

1 to 4 are diagrams showing a conventional corona discharge device having an ozone decomposition function, FIG. 5 is a perspective view of the corona discharge device applied to the present invention, FIG. 6 is a sectional view thereof, and FIG. 7 and FIG. 8 are diagrams showing an embodiment of the present invention. 10... Corona discharge device main body, 11... Back electrode, 12... Heater, 13... Heat resistant insulating member,
14... Excitation electrode, 16... Power supply for heater, 17
...High voltage AC power supply.

Claims (1)

[Claims] 1. A back electrode formed of a metal plate, a heat-resistant insulating member covering the entire surface of the back electrode, and a thin wire-shaped excitation member fixed to one side of the back electrode via the heat-resistant insulating member. A corona discharge comprising an electrode, a power source for applying an alternating current voltage between the back electrode and the excitation electrode, and a heating means fixed to the other side of the back electrode via the heat-resistant insulating member. 1. A corona discharge device, wherein the surface of the heat-resistant insulating member facing the object to be charged has a shape corresponding to the shape of the object to be charged.