JPH04133075A - Corona discharger for electrophotographic device - Google Patents

Abstract

PURPOSE:To increase producibility and to attain reduction in cost by integrally forming a corona discharging electrode used for the electrification and destaticization of a photosensitive body with a conductive member having plural protruding parts. CONSTITUTION:One iron plate is removed like a needle, its top end is shaped to obtain an accurate angle by grinding or polishing or so. Then, a needle part 12 is bent, to form an electric conductor supporting part 14, and a corona discharging electrode 10 is obtained. Then, the corona discharging electrode 10 is disposed inside a shield via an insulating wire supporting member 30. Then, a grid 40 is attached to the opening part of the shield 20 via the insulating supporting member 50. Thus, the corona discharger is produced in a simple process and at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a corona discharge device for an electrophotographic apparatus used for charging and neutralizing a photoreceptor in an electrophotographic process.

[Prior Art] Conventionally, a corona discharge device for an electrophotographic apparatus has used a corona wire such as a tungsten wire as a corona discharge electrode, as shown in FIG. 6, for example.

That is, both ends of the corona wire 60 are fixed to an insulating support part 62, and the insulating support part 62 is fixed to a shield member 64. A grid 66 is supported by an insulating support portion 68 in the opening of the shield member 64 . The corona wire 60 is given an appropriate tension by a spring or screw (not shown).

A corona discharge device having the above configuration is placed parallel to the surface of the photoreceptor, and the photoreceptor is charged or neutralized by applying a voltage of an appropriate value to the corona wire 60 and the lid 66.

However, in such a corona discharge device, when a voltage of several kilovolts is applied to the corona wire, the corona wire vibrates, resulting in uneven charging of the photoreceptor. The vibration of the corona wire becomes larger as the corona discharge device becomes larger and the wire becomes longer, the larger the amplitude and the more uneven charging becomes.
It was difficult to increase the size of the device.

In order to solve this problem, a corona discharge device has been proposed that uses a corona discharge electrode in which a plurality of needles are arranged to eliminate charging unevenness, as shown in FIG. 7, for example. This is a corona discharge electrode in which needles are arranged on a conductive support member instead of a corona wire.

That is, in FIG. 7, the corona discharge electrode 70 includes a plurality of needles 72 arranged in a line at equal intervals, and a conductive support member 74 that holds the needles 72. The corona discharge electrode 70 includes an insulating support member 7
8 and is disposed within the shield 76 and the shield 7
A grid 80 is attached to the opening 6 via an insulating support member 82. The corona discharge electrode 70, shield 76 and grid 80 are electrically insulated by insulating support members 78, 82, respectively.

When the corona discharge device having the above configuration is arranged parallel to the surface of the photoreceptor and an appropriate voltage is applied to the corona discharge electrode 70 and the grid 80, as in the case of the above-mentioned corona wire method, the needle 72 Corona discharge occurs at the tip of the photoreceptor, and the photoreceptor is charged or neutralized.

According to this configuration, since the needle has much higher rigidity than the wire, almost no vibration occurs, and the above-mentioned corona discharge device enables uniform charging.

[Problems to be Solved by the Invention] In the corona discharge device using the above-mentioned needles, in order to perform uniform and stable charging, it is necessary to maintain the distance between each needle, the height of the needle tip, etc. constant. there were. However, in the above-mentioned corona discharge device, the corona discharge electrode is composed of a plurality of needles and a conductive support member, and the needles are arranged at equal intervals with their tips aligned and fixed on the conductive support member. As a result, the manufacturing process became complicated and there was a problem of poor productivity.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a corona discharge device for an electrophotographic apparatus that is inexpensive and has high productivity.

[Means for Solving the Problem] In order to achieve this object, in the corona discharge device of the present invention, the corona discharge electrode is integrally formed with a conductive member having a plurality of protrusions.

[Function] In the present invention, since the corona discharge electrode is integrally formed with a conductive member having a plurality of protrusions, a corona discharge device in which uneven charging is less likely to occur can be easily manufactured at low cost.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

First, the configuration will be explained with reference to FIG. The corona discharge electrode 10 is press-molded from two iron plates, and is integrally formed with a plurality of needle parts (protrusions) 12 whose tips are machined at acute angles and a conductive support part 14 . The corona discharge electrode 10 is connected to the shield 2 via an insulating support member 30.
0, and a grid 40 is attached to the opening of the shield 20 via an insulating support member 50. The corona discharge electrode 10. The shield 20 and the grid 40 are electrically insulated by insulating support members 30 and 50, respectively.

Next, the operation will be explained. A corona discharge device having the above configuration is arranged parallel to the surface of the photoreceptor, and the corona discharge electrode 1
Applying a voltage of several KV to 0 and several hundred μ to the grid 40,
By grounding the shield 20, a corona discharge is generated at the tip of each needle portion 12. In that state,
By moving either the corona discharge device or the photoreceptor at a constant speed in a direction perpendicular to the direction in which the needle portions 12 are arranged, the entire surface of the photoreceptor is uniformly charged.

The corona discharge electrode 1o is made by a simple process of first cutting out a single iron plate into a needle shape, cutting or polishing the tip to an acute angle, and then bending the needle portion 12. Therefore, it can be manufactured at low cost and has very high productivity. Furthermore, since the punching process is performed using a die, the accuracy of the spacing between the two dowels, the position of the tip, etc. is maintained.

[Modifications] The present invention is not limited to the embodiments described in detail above, and various changes can be made without departing from the spirit thereof.

For example, the needle portions 12 may be arranged in two rows as shown in FIG. In this case, it is possible to increase the charging potential of the photoreceptor even with the same charging time. By arranging the needle portions 12 in a staggered manner as shown in FIG. 3, it is possible to further prevent portions of low charging potential from occurring between adjacent needle portions 12. In addition, as shown in Figure 4, if the corona discharge electrode is made by punching out a single iron plate and cutting the tip obliquely, and the bending process is also omitted, the cost can be lowered and productivity can be improved. . If the shape is punched into a saw blade shape as shown in FIG. 5, two corona discharge electrodes can be made in one press without wasting material, which can further reduce costs.

[Effects of the Invention] As is clear from the detailed description above, the present invention provides a corona discharge device in which charging unevenness is less likely to occur because the corona discharge electrode is integrally formed with a conductive member having a plurality of protrusions. It has the advantage of being cheap and easy to make.

Further, by arranging the projections in a plurality of linear rows, there is an effect that the charging potential of the photosensitive zone can be increased even with the same charging time.

Furthermore, by arranging the protrusions in a staggered manner, it is possible to prevent the charging potential from decreasing between adjacent protrusions.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a corona discharge device showing one embodiment embodying the present invention, and FIGS. 2 to 5 are plan views and perspective views showing other embodiments of the corona discharge electrode, respectively. . FIGS. 6 and 7 are exploded perspective views of a conventional corona discharge device. In the figure, 10 is a corona discharge electrode, 12 is a needle part (protrusion part), 14 is a conductive support part, 2o is a rolled member, 30
is an insulating support member, and 40 is a grid.

Claims (1)

[Claims] 1. A corona discharge electrode, a shield member surrounding the corona discharge electrode and having at least a corona discharge opening, electrically insulating the corona discharge electrode and the shield member, an insulating support member that supports the corona discharge electrode; and a corona discharge device for an electrophotographic apparatus, wherein the corona discharge electrode is integrally formed with a conductive member having a plurality of protrusions. Corona discharge device for photographic equipment. 2. The corona discharge device for an electrophotographic apparatus according to claim 1, further comprising a grid at an opening of the shield member. 3. The corona discharge device for an electrophotographic apparatus according to claim 1 or 2, wherein the projections of the corona discharge electrode are linearly arranged in one or more rows. 4. The corona discharge device for an electrophotographic apparatus according to claim 1 or 2, wherein the projections of the corona discharge electrode are arranged in a staggered manner.