JPH09160346A - Corona electrification device for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely support an electrode plate with a very simple supporting constitution and to obtain an excellent duplicate image by composition an electrode supporting member capable of supporting end parts of a plate like electrode so as to hold it either end. SOLUTION: On the electrode supporting members 111 and 112 provided on the either end of the planer electrode 13, the electrode supporting parts 113 and 114 is severally composed as the supporting member being held in close contact with either surface of the either end of the planer electrode 13 at least, with tooth-shaped electric discharging plate 12. Then, the electrode supporting members 111 and 112 are respectively fixed to either end of a shielding plate 14 whose sectional plane is formed in a shape of L-type as a back plate. As for a fixing method, fixing by a screw is suitable but the fixing may be made by an adhesive. Moreover, one end of the planer electrode 13 is elastically supported by an elastic member 115 provided in the electrode supporting member 111, and the other end is engaged with a locking part 116 provided inside the electrode supporting member 112. Furthermore, between the one end of the planer electrode 13 and a terminal 117 provided on the electrode supporting member 112 for connecting to an external power source is connected with a leading wire 118.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona charging device using a non-contact type sawtooth electrode which is mainly used for charging a photosensitive member in an electrophotographic image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, discharge electrodes for electrophotographic corona discharge are roughly classified into a wire discharge system (corotron, scorotron, dicorotron, etc.) and a pin discharge system (pin electrode type, serrated electrode type, etc.). It Since the latter produces a small amount of ozone, it has recently been used in electrophotographic copying machines, printers and the like. In particular, a charger having a structure using an electrode plate in which a plurality of saw-toothed electrode portions are provided on one thin plate member is disclosed in JP-A-63-15272 and JP-A-5-152272.
-45999 gazette etc. are disclosed. A structure in which the serrated electrode portion is held by a part of the corona charging device main body and is detachable is disclosed in Japanese Patent Laid-Open No. 5-289471, and both side surfaces of the serrated electrode portion are entirely held. The structure is disclosed in JP-A-6-83167. Further, a structure in which one of the serrated electrode portions is held by a spring member is disclosed in Japanese Patent Laid-Open No. 7-234570.

[0003]

However, although such a serrated electrode plate is excellent in discharge performance, it is rigid because a thin plate-shaped metal plate such as stainless steel having a thickness of about 0.1 mm is used. In order to hold the sawtooth electrode plate in the correct position, it is necessary to use a high-precision machined member and attach it to a resin member made to hold the accurate position. However, there is a problem in that such members are expensive to process, and that all the electrode plates cannot be manufactured to a desired accuracy by the attaching work.

Further, the structure described in Japanese Patent Laid-Open No. 6-83167, which holds the entire both side surfaces of the sawtooth electrode portion, increases the number of parts of the electrode device and makes the structure complicated.
Further, in the structure in which one of the electrode plates is held only by the spring member as in Japanese Patent Laid-Open No. 7-234570, the apparatus vibrates at the time of operation such as movement of the optical system or start of sheet feeding, and performs a good charging action. I can't do it.

As a result of solving and improving this point, the present invention provides
The purpose is to accurately support the electrode plate with a very simple holding structure and to provide a good copy image.

[0006]

In order to achieve the above object, the present invention provides a corona charging device according to claim 1, wherein a saw-tooth discharge portion of a plate-shaped electrode is opposed to an object to be discharged to discharge the object. The apparatus has an electrode supporting member having a supporting portion for supporting a part of an end portion of the plate electrode, wherein the electrode supporting member is provided at both ends of the plate electrode. And supporting both side surfaces of both ends of the plate-like electrode and the sawtooth discharge part side, wherein the electrode supporting member is provided at both ends of the back plate, Item 4 is achieved by providing an elastic member between the electrode supporting member and the plate electrode.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Prior to the description of the embodiments of the present invention, the structure and operation of a copying machine in which the corona charging device of the present invention is used will be described.

FIG. 1 is a sectional view of an image forming apparatus using the corona charging device of the present invention.

In FIG. 1, reference numeral 10 denotes a photosensitive drum, which is an image bearing member, which is formed by coating a photosensitive member 101 (organic photosensitive member) on a drum base, and is grounded and driven to rotate clockwise in the drawing. To be done. Reference numeral 11 denotes a corona charger. The corona charger 11 is composed of a plate-shaped electrode 13 having a saw-tooth discharge portion 12 formed therein. The saw-tooth discharge portion 12 provided in the shield plate 14 charges the surface of the photosensitive member 101. Performs an imparting charging action. Prior to the charging action, the photoconductor 1 up to the previous printing
P using a light emitting diode to eliminate the history of 01
The photoconductor 1 is exposed to light by a CL (pre-charging static eliminator) 15.
Remove the static electricity from 01.

After the photosensitive drum 101 is uniformly charged to the photosensitive drum 101, the image exposing means 16 performs image exposure based on an original image or an image signal, and the photosensitive drum 101 of the photosensitive drum 10 contains toner. Developing devices 17 each containing a developer including a carrier are provided, and a developing sleeve 18 that contains a magnet, holds the developer, and rotates is used for development. The developer consists of a carrier in which ferrite is used as a core and is coated with an insulating resin around it, and a toner whose main component is polyester and pigments according to the color and charge control agents, silica, titanium oxide, etc. are added. The developer is a developing sleeve 1 by means of a layer forming means.
8 is regulated to have a layer thickness (developer) of 100 to 600 μm and is conveyed to the developing area.

The gap between the developing sleeve 18 and the photosensitive member 101 in the developing area is 0.2 to more than the layer thickness (developer).
The bias voltage is applied during this time. Thus, the image forming process is performed by the developer, and a visible image is formed by the toner on the peripheral surface of the photoconductor 101.

On the other hand, although not shown, one transfer material (hereinafter referred to as recording paper) P conveyed by the conveying member 21 from the paper feeding cassette through the paper feeding roller is temporarily stopped by the stop member 19,
When the transfer timing is adjusted, the stop member 19 is operated by the operating means 20 to release the recording paper P, and the registration roller 2
The sheet is fed to the transfer area by the rotation operation of 11.

In the transfer area, the recording paper P fed by the transfer pole 22 serving as the transfer means is attracted or adhered to the peripheral surface of the photoconductor 101 of the photoconductor drum 10 in synchronism with the transfer timing so as to adhere the toner to the toner. The image is transferred.

Next, the recording paper P is neutralized by the separation pole 23, separated from the peripheral surface of the photoconductor drum 10, and then conveyed to the fixing device 24 to be heated roller (upper roller) 25 and pressure roller (lower roller) 26. After the toner is fused by heating and pressurizing, the toner is discharged to the outside of the apparatus.

On the other hand, the photosensitive drum 1 from which the recording paper P is separated
In No. 0, the residual toner is removed and cleaned by the pressure contact of the blade 28 of the cleaning device 27, the charge is again removed by the PCL (pre-charging static eliminator) 15 and the corona charging device 11 charges the next toner image forming process. enter.

FIG. 2 is a sectional view showing a concrete structure of the corona charging device 11 of the present invention. In the figure, the plate-shaped electrode 13 on which the saw-tooth discharge section 12 for charging the photosensitive member 101 is formed is made of a stainless material having a thickness of about 0.1 mm, and is formed by an etching process. A large number of saw teeth are formed at equal intervals on the side edge of the body drum 10 facing the image area of the photoconductor 101, and are installed so as to face the surface of the photoconductor 101 with a predetermined gap.

Electrode support members 111 and 112 are provided at both ends of the plate electrode plate 13. The electrode support member 11
Electrode support portions 113 and 114, which are support members that are in close contact with at least the sawtooth discharge portion 12, are formed on both side surfaces of both ends of the plate electrode plate 13 and 112, respectively. The electrode supporting members 111 and 112 are fixed to both ends of the shield plate 14 which is the back plate and has a U-shaped cross section. As a fixing method, fixing with screws is suitable, but fixing with an adhesive may be used. Further, one end of the plate-shaped electrode 13 is elastically supported by the elastic member 115 provided in the electrode supporting member 111, and the other end is provided in the electrode supporting member 112.
Lock to 16. In addition, a terminal 117 connected from one end of the plate electrode 13 to an external power source provided on the electrode supporting member 112.
Conductors 118 are connected between them.

3 (a), 3 (b) and 3 (c) show an embodiment of the electrode supporting portion 113 formed on the electrode supporting members 111 and 112 of the corona charging device 11 of the present invention.

The electrode supporting member 111 will be described below as an example.

In FIG. 3 (a), the electrode support portion 113 formed on the electrode support member 111 has projections 119 and 120 for supporting two positions on both sides of the plate electrode 13 and a support for supporting the sawtooth discharge portion 12 side. An embodiment is shown in which a part 121 and a support part 122 that supports the non-discharge side of the electrode support part 113 are formed. In this way, the one end of the plate electrode 13 is securely supported at six places, and vibration is prevented during corona discharge of the plate electrode 13.

FIG. 3 (b) shows an embodiment of a support portion 123 formed accurately on the electrode support portion 113 formed on the electrode support member 111, which has substantially the same shape as the cross section of one end of the plate electrode 13. In this way, by reliably supporting the entire surface of one end of the plate electrode 13, vibration can be reliably prevented during corona discharge of the plate electrode 13.

In FIG. 3C, the electrode supporting portion 113 formed on the electrode supporting member 111 has projections 124 and 125 for supporting one side of the plate electrode 13 and a supporting member for supporting the sawtooth discharge portion 12 side. An embodiment is shown in which a portion 126 and a support portion 127 that supports the non-discharge side of the electrode support portion 113 are formed. In this way, the one end of the plate electrode 13 is securely supported at four places,
Vibration is prevented during corona discharge of the plate electrode 13.

FIG. 4 is a perspective view showing the overall structure of the corona charging device 11 of the present invention.

[0024]

As described above, according to the present invention, in claim 1, the plate-shaped electrode is constituted by the electrode supporting member for holding the end portion so as to sandwich it. When the charge is applied to the photoconductor from the sawtooth discharge part of the plate electrode by corona discharge, the charge can be applied with the required accurate discharge without directly receiving the vibration of the device. Good image formation can be obtained.

In the present invention, the electrode supporting members are provided at both ends of the plate electrode, and support both side surfaces of both ends of the plate electrode and the sawtooth discharge portion side. In particular, since both side surfaces of the plate-like electrode and the saw-tooth discharge portion side are supported at both end sides, good image formation can be obtained without receiving vibration of the apparatus.

In the third aspect, since the electrode supporting members are provided at both ends of the back plate, it is easy to attach and replace the plate electrode, and both ends of the plate electrode can be surely supported. .

In the fourth aspect, the electrode supporting member,
Since the elastic member is provided between the plate-shaped electrodes, a constant tension is applied to the plate-shaped electrodes, and both side surfaces of both ends of the plate-shaped electrode and the saw-tooth discharge portion side are supported. The plate-shaped electrode is not vibrated at the installation position even if it is subjected to the above vibration, and good image formation can be obtained by a good charging action.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of an image forming apparatus using a corona charging device of the present invention.

FIG. 2 is a sectional view of a corona charging device of the present invention.

FIG. 3 is a sectional view showing an electrode supporting portion of an electrode supporting member of the corona charging device of the present invention.

FIG. 4 is a perspective view showing a corona charging device of the present invention.

[Explanation of reference numerals] 10 photoconductor drum 101 photoconductor 11 corona charging device 12 sawtooth discharge part 13 plate electrode 17 developing device 111, 112 electrode support member 113, 114 electrode support part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Koshimura 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica Stock Company

Claims (4)

[Claims] 1. A corona charging device for discharging electric discharge to an object to be discharged by causing a sawtooth discharge part of the plate electrode to face the object to be discharged, and having a supporting part for supporting an end of the electrode plate. A corona charging device for an image forming apparatus, comprising an electrode supporting member. 2. The electrode supporting member is provided at both ends of the plate electrode, and supports both side surfaces of both ends of the plate electrode and a sawtooth discharge portion side. 1
A corona charging device for the image forming apparatus described. 3. The corona charging device for an image forming apparatus according to claim 2, wherein the electrode supporting member is provided at both ends of the back plate. 4. An elastic member is provided between the electrode supporting member and the plate-shaped electrode.
A corona charging device for the image forming apparatus described.