JPH09160348A - Corona electrifier for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corona electrifier capable of making one sheet of electrode plate usable over along period at a low cost, while making one hand of a tooth-shaped electric discharge part usable, after the use of the electric discharge part on the other hand, by providing the tooth-shaped electric discharge part on the opposite side end part of the tooth-shaped electric discharge side for executing discharge of a planar electrode. SOLUTION: The planar electrode 13, on which the tooth-shaped electric discharge parts 12 and 121 for electrifying a photoreceptor 101 is formed on a peripheral edge in the lengthwise direction, is made of a stainless material whose thickness is approximately 0.1mm, and is formed by means of etching work. Then, a number of tooth- shapes are formed with the same space on the side edge facing the image area on the photoreceptor 101 of the photoreceptor drum 10 being an charge receiving body, and set opposite to the surface of the photoreceptor 101 with a specified space. When the discharging efficiency of one side of the tooth-shaped electric discharge part 12 on the planer electrode 13 is reduced, the other side of tooth-shaped electric discharge part 121 can be immediately switched to be used, therefore the need of newly replacing the planer electrode is eliminated, and the switching operation can be quickly performed.

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 serrated 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 sawtooth-shaped electrode portions are provided on one thin plate member is disclosed in JP-A-63-15272 and JP-A-5-157272.
It is disclosed in Japanese Patent Publication No. 45999. Further, a structure in which a serrated electrode part is held in a part of the corona charging device main body and is detachable is disclosed in JP-A-5-289471, and a plate electrode is used as a holder in the corona charging device. A structure of supporting and fixing is disclosed in Japanese Patent Laid-Open No. 84440.

[0003]

When the corona discharge action is performed, the serrated electrode plate is discharged and charged from the serrated tip. Therefore, if dust and toner used for development adhere to the serrated tip due to the discharge action, the discharge effect is significantly reduced. Therefore, a means for exchanging the sawtooth electrode plate together with the supporting member is disclosed in JP-A-5-289471.
As disclosed in Japanese Patent Laid-Open Publication No. JP-A No. 2003-187, such replacement requires the electrode plate to be discarded, which has the disadvantages of increasing maintenance costs and requiring a lot of time for disposal. Further, as described above, as a means for activating the cleaning device and reusing the sawtoothed electrode plate when dust and toner used for development adhere to the sawtoothed electrode plate as described above, it is disclosed in Japanese Patent Laid-Open No. 7- Although there is Japanese Patent No. 84440, when the cleaning device as described above is attached, the entire corona charging device becomes large in size, and a mechanism and a drive device for operating the cleaning device are required, which makes the entire device expensive.

As described above, the conventional corona charging device using the serrated plate-like electrode plate increases the maintenance cost because the used electrode plate is replaced and discarded, and a cleaning device is required for cleaning. Therefore, there is a drawback that the corona charging device becomes large in size.

The present invention has been made to solve the above drawbacks and has been improved. A sawtooth discharge portion is formed on both edges in the longitudinal direction of an electrode plate, and after using one discharge portion, the other sawtooth discharge portion is used. It is an object of the present invention to provide a corona charging device in which one electrode plate can be used inexpensively and can be used for a long period of time.

[0006]

To achieve the above object, according to the present invention, in claim 1, a corona for discharging electric discharge to a discharged body by causing a tip of a serrated discharge portion of a plate electrode to face the discharged body. In the charging device, a saw-tooth discharge part is provided at an end opposite to the saw-tooth discharge part for discharging the plate-like electrode, wherein the electrode supporting member has both ends of the plate-like electrode. The non-discharging member is provided on the non-discharging side sawtooth discharge portion provided on the opposite end portion, and the non-discharging member is an electrode mounting member. In claim 4, the plate-shaped electrode is detachably provided from the electrode mounting member, and in claim 5, the plate-shaped electrode is a non-discharge side sawtooth-shaped discharge portion side of the electrode mounting member. It is achieved by being formed in an L shape so that it can be stored in.

[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.

In FIG. 1, reference numeral 10 denotes a photosensitive drum, which is an image bearing member, which is formed by coating an OPC photosensitive member 101 (organic photosensitive member) on a drum base and is grounded and driven clockwise in the drawing. Is rotated. Reference numeral 11 is a corona charger, and the corona charger 11 is a plate electrode 1 having a sawtooth discharge portion 12 formed thereon.
3, the discharge portion 12 provided in the shield plate 14 performs a charging action of giving a charge to the surface of the photoconductor 101. 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 photoconductor 101 of the photoconductor drum 10 is uniformly charged, the image exposure means 16 performs image exposure based on an original image or an image signal to face the photoconductor surface 101 of the photoconductor drum 10. A developing device 17 in which a developer composed of toner and a carrier is contained is provided, and the development is performed by a developing sleeve 18 which contains a magnet and holds and rotates the developer. 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 agent is regulated by the layer forming means to have a layer thickness (developer) of 100 to 600 μm on the developing sleeve 18 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. In this way, the image forming process is performed with the developer,
A visible image of toner is formed 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 released by the operation of the operating means 20, and the registration roller 211 is rotated to feed the sheet to the transfer area.

In the transfer area, in synchronization with the transfer timing, the recording paper P fed by the transfer pole 22 serving as the transfer means is sandwiched around the peripheral surface of the photosensitive body 101 of the photosensitive drum 10 to form a toner image. Is transcribed.

Next, the recording paper P is destaticized by the separation pole 23, separated from the peripheral surface of the photosensitive drum 10, and then conveyed to the fixing device 24 where it is heated (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 10 from which the recording paper P has been separated removes and cleans the residual toner by pressing the blade 28 of the cleaning device 27.
The PCL (pre-charging static eliminator) 15 again removes electricity, and the corona charger 11 receives the charge to start the next image forming process.

FIG. 2 is a sectional view showing a specific structure of the corona charger 11 of the present invention. In the figure, a plate-shaped electrode 13 having saw-tooth discharge parts 12 and 121 for charging the photosensitive member 101 formed on the peripheral edge in the longitudinal direction is made of a stainless material having a thickness of about 0.1 mm, and is etched. A large number of saw teeth are formed at equal intervals on the side edge of the photoconductor drum 10, which is a member to be discharged, which faces the image area of the photoconductor drum 10 and is formed so as to face the surface of the photoconductor 101 with a predetermined gap. is set up.

Electrode support members 111 and 112 are provided at both ends of the plate electrode plate 13, and the electrode support member 11 is provided.
Both end portions are fixed to fixing members 113 and 114 by fixing members 113 and 114, respectively. Further, the electrode supporting members 111 and 112 are shield plates 14 having a U-shaped cross section which is a back plate.
It is fixed at both ends. As a fixing method, the fixing screws 141 and 142 are used for fixing. Further, one end of the plate-shaped electrode 13 is partially formed on the shield plate 14, and an electrode mounting member 115, which is a non-discharge member made of an insulating material, is provided in the mounting groove 116 formed in the electrode mounting member 115. The unused saw-tooth discharge portion 121 side of the plate electrode 13 is detachably inserted and fixed. The insertion method is a method of sequentially inserting from the side of the attachment groove 116 formed in the electrode attachment member 115. Alternatively, it may be inserted from above the mounting groove 116. Further, the electrode mounting member 115 may be provided so as to prevent discharge of the unused saw-tooth discharge portion 121, and may not be provided particularly inside the shield plate 14. When the electrode mounting member 115 is attached, the fixing screw 14 for fixing the electrode supporting members 111 and 112 provided on both ends of the shield plate 14 is used.
1, 142 are removed, and the electrode support members 111, 112 are removed from the shield plate 14. Next, after inserting the plate-shaped electrode 13 into the mounting groove 116, the terminals 117 connected to the external power source provided on the electrode support member 112 are connected by the conduction member 117, and the electrode support members 111 and 112 are again connected to the shield plate 14.
Then, it is fixed with fixing screws 141 and 142.

FIG. 3A shows the corona charger 1 shown in FIG.
The longitudinal section of 1 shows the attachment / detachment direction of the plate electrode 13. The plate-shaped electrode 1 is formed in the mounting groove 116 formed in the electrode mounting member 115.
The sawtooth-shaped discharge portion 121 side of No. 3 is inserted. When the corona charger 11 is used for a long period of time and dust, toner, or the like adheres to the sawtooth discharge portion 12 of the plate electrode 13 to reduce the discharge efficiency, the plate electrode is moved from the mounting groove 116 in the direction of the arrow. 13 is removed, the sawtooth discharge portion 12 side is inserted into the mounting groove 116 and fixed, and is disposed outside so that the unused sawtooth discharge portion 121 side can discharge.

FIG. 3B shows another embodiment of the corona charger 11. As shown in the figure, the plate electrode 131 is bent into an L-shape, and saw-tooth discharge parts 12 and 121 are formed at both ends in the longitudinal direction, respectively, and a non-discharge in which the L-shape mounting groove 120 is formed in the shield plate 14. The electrode mounting member 119 that is a member for use is provided, and similarly to the above, the fixing screws 141 and 142 that fix the electrode supporting members 111 and 112 provided at both ends of the shield plate 14 are removed to remove the electrode supporting members 111 and 112 from the shield plate 14. Remove. Next, the L-shaped mounting groove 120
After sequentially inserting the plate-shaped electrodes 131 from the end portions of the L-shaped mounting groove 120, the saw-tooth discharge portion 12 is placed outside and the saw-tooth discharge portion 121 side is placed inside and fixed from the end position of the L-shaped mounting groove 120. After that, the electrode supporting members 111 and 112 are fixed to the shield plate 14 as described above.

When the corona charger 11 is used for a long period of time and dust, toner or the like adheres to the saw-tooth discharge portion 12 of the plate electrode 13 to lower the discharge efficiency, the corona charger 11 is pulled out from the L-shaped mounting groove 120. The plate-shaped electrode 131 is removed, and then the used saw-toothed discharge portion 12 side is inserted into the L-shaped mounting groove 116 and fixed, so that the unused saw-toothed discharge portion 121 side which is not discharged can be discharged outside. To place. The electrode mounting member 119 of the present embodiment does not have to be provided inside the shield plate 14 as described above, and may be provided at a position that prevents discharge of the unused sawtooth discharge portion 121.

FIG. 4 is a perspective view showing the overall structure of the corona charger 11 of the present invention. As shown in the figure, the saw-tooth discharge part 12 of the plate electrode 13 is installed so as to be discharged from the opening of the U-shaped shield plate 14, and both ends of the plate electrode 13 are electrode supporting members 111 and 112. The unused saw-toothed discharge part 121 of the plate-shaped electrode 13, which is supported and fixed, is mounted in the electrode mounting member 115 provided on the shield plate 14 so as not to discharge, and is shown in FIG. 1 in this state. Thus, the corona charger 11 is installed.

[0020]

As described above, according to the first aspect of the present invention, one sawtooth discharge portion of the plate electrode is provided on the outside so as to be discharged, and the other sawtooth discharge portion that is not discharged is corona. Since it is provided in the charging device, when the discharge efficiency of one sawtooth discharge part decreases, it can be immediately switched to the other sawtooth discharge part, so there is no need to replace and install a new plate electrode. , Switching operation can be done quickly,
Cost reduction is possible.

According to a second aspect of the present invention, both ends of the plate electrode are supported by electrode supporting members provided at both ends of the back plate, and the plate is provided in the groove of the electrode mounting member made of an insulating material provided in the back plate. By providing the other saw-tooth discharge part that does not discharge the strip electrode, the thin plate electrode is stably installed in the corona charging device, and the discharge action of the plate electrode is also stable. A good image can be obtained.

According to the third aspect of the invention, since the plate electrode is provided so as to be detachable from the groove of the electrode mounting member made of an insulating material, when the discharge efficiency of one sawtooth discharge portion is lowered, the plate electrode is quickly It can be used by switching to the other sawtooth discharge part.

According to the present invention, since the other sawtooth discharge portion of the plate electrode which is not discharged is bent and provided on the insulating support, the corona charging device can be downsized.

[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 vertical cross-sectional view showing an insulating support and a plate electrode provided on a back plate 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 symbols]

 10 Photoreceptor Drum 101 Photoreceptor 11 Corona Charger 12,121 Sawtooth Discharge Section 13 Plate Electrode 115,119 Electrode Mounting Member 111,112 Electrode Supporting Member

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

Claims (5)

[Claims] 1. In a corona charging device that discharges the plate-shaped electrode by causing the tip of the saw-shaped discharge part of the plate-shaped electrode to face the plate-shaped electrode, the side of the saw-tooth discharge part that discharges the plate-shaped electrode. A corona charging device for an image forming apparatus, characterized in that a sawtooth discharge portion is provided at an end portion on the opposite side to. 2. An electrode supporting member is provided to support both ends of a plate-like electrode, and a non-discharging member is provided to a sawtooth discharge portion on the non-discharging side provided at the opposite end portion. Item 2. A corona charging device for an image forming apparatus according to item 1. 3. The corona charging device for an image forming apparatus according to claim 2, wherein the non-discharge member is an electrode mounting member. 4. The corona charging device for an image forming apparatus according to claim 2, wherein the plate-shaped electrode is detachably attached to the electrode mounting member. 5. The image according to claim 2, wherein the plate-like electrode is formed in an L shape so that the saw-tooth discharge portion side of the non-discharge side is housed in the electrode mounting member. Corona charging device for forming equipment.