JP3521371B2 - Corona charging device for image forming equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[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.

[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 is structurally complicated. Further, since the discharge action is performed by one sawtooth electrode portion, there is a defect that the discharge efficiency is reduced in a short period of time.
Further, a structure in which a saw-toothed electrode portion is detachably attached together with a supporting member fixed thereto is described in JP-A-5-289471, but a gap is provided between the supporting member supporting the electrode plate and the corona charging device at the time of use. The charging performance becomes unstable due to vibration during operation of the image forming apparatus. Even in this structure, since the discharge action is performed by the single sawtooth electrode portion as described above, the discharge efficiency is reduced in a short period of time.

An object of the present invention is to accurately support a plurality of electrode plates on a corona charging device and provide a good copy image for a long period of time.

[0006]

Means for Solving the Problems The above-mentioned objects are as follows.
Achieved by 1. Place the sawtooth discharge part of the plate electrode facing the object to be discharged.
A corona charging device for an image forming apparatus that discharges an object to be discharged
A plurality of sheets forming the sawtooth discharge parts in a plurality of rows
Of the plate-like electrode, a supporting member for supporting the plate-like electrode, and
And supporting the support member at both ends of the support member 2
A plurality of electrode support members, and the electrode support members
Forming a support surface for supporting the holding member,
Connect the terminal of the external power supply to one of the
The holding member and the supporting member are connected by an elastic member.
Corona charging device for image forming equipment. 2. Place the sawtooth discharge part of the plate electrode facing the object to be discharged.
A corona charging device for an image forming apparatus that discharges an object to be discharged
In the cross-sectional shape that forms the sawtooth discharge parts in a plurality of rows.
The plate-like electrode having a U-shape or U-shaped cross section, and the plate-like electrode
Has two electrode supporting members for supporting the
Forming a support surface for supporting the plate electrode on the pole support member,
When an external power supply terminal is connected to one of the electrode supporting members
Together, the electrode supporting member and the plate-like electrode are elastic members.
Corona charging of image forming apparatus characterized by connecting with
apparatus. 3. It has a leaf spring, and the plate spring supports the plate electrode by the leaf spring.
Position the sawtooth discharge part by pressing on the surface
The image forming apparatus according to the above item 2 is characterized in that
Rona charging device.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to the description of the preferred 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 shows an image forming apparatus using the corona charging device of the present invention. Reference numeral 10 denotes a photosensitive drum which is an image bearing member, and is a photosensitive drum 101 (organic photosensitive member) formed by coating on a drum base, which is grounded and driven and rotated clockwise. Reference numeral 11 is a corona charger, and the corona charger 11 is formed with a plurality of plate-shaped electrodes 13 and 131 which form saw-tooth discharge parts 12 and 121 and are fixedly supported by a supporting member 132. Saw-tooth discharge part 1 provided in
2, 121 performs a charging action of giving an electric charge to the surface of the photoconductor 101. Prior to the charging operation, in order to eliminate the history of the photosensitive member 101 up to the previous printing, the photosensitive member 101 is discharged by exposure by a PCL (pre-charging static eliminator) 15 using a light emitting diode or the like.

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, and the photoconductor 1 of the photoconductor drum 10 is exposed.
01 is provided with a developing device 17 in which a developer including a toner and a carrier is contained, and a developing sleeve 18 that contains a magnet and holds the developer and rotates is used for development. The developer is composed of a carrier in which a ferrite core is coated with an insulating resin around the core, and a pigment whose main material is polyester and a charge control agent, silica, titanium oxide, etc. are added to the carrier. Is regulated to a layer thickness (developer) of 100 to 600 μm on the developing sleeve 18 by the layer forming means, 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).
A bias voltage is applied during this period with a length of 1.0 mm. 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 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 a 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 in order to transfer the toner. The image is transferred.

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.
Again, the PCL (pre-charging static eliminator) 15 receives static electricity and the corona charger 14 charges it 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, the plate-shaped electrode 13 on which the saw-tooth discharge portion 12 for charging the photosensitive member 101 is formed is made of a stainless steel 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 photoconductor 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.

In this embodiment, the plate electrode 13 and another plate electrode 131 are provided. The plate electrode 1
3, 131 are fixed to the support member 132 on both sides with adhesives 135, 136, and both ends of the support member 132 are provided on the electrode support members 111, 112. Both ends of the support member 132 have upper support surfaces 1131 and 1141 and lower support surfaces 11 formed on the electrode support members 111 and 112, respectively.
The upper support surface 1131,1 is supported by 3,114.
141, the position of the support member 132 is determined,
The distance between the saw-tooth discharge parts 12 and 121 formed in the longitudinal direction of the tip edges of the plate electrodes 13 and 131 and the photoconductor 101 is accurately maintained.

Further, the electrode supporting members 111 and 112 are shield plates 1 having a U-shaped cross section which is a back plate.
It is fixed to both ends of 4. As a fixing method, fixing with screws is suitable, but fixing with an adhesive may be used.
Further, one end of the supporting member 132 is connected to the electrode supporting member 111.
It is elastically held by an elastic member 115 provided inside and the other end is locked to a locking portion 116 provided inside the electrode support member 112. Further, a lead wire 118 connects between one end of the plate electrode 13 and a terminal 117 provided on the electrode support member 112 and connected to an external power source.

In order to facilitate the mounting work,
The lower support surfaces 113 and 114 are formed on the lid members 119 and 120 that are detachably provided so that a part of the electrode support members 111 and 112 can be opened, and the lid members 119 and 120 are formed.
Is fixed to the electrode support members 111 and 112, the support member 132 reliably contacts the upper support surfaces 1131 and 1141 via the lower support surfaces 113 and 114,
It is placed in the correct position.

FIG. 3 is a sectional view taken along line AA of FIG. 2, in which the plate electrodes 13 and 131 are fixed to both sides of the support member 132 with adhesives 135 and 136 (double-sided tape may be used). The lid member 119 is attached to the upper support surface 1141 of the electrode support member 112 so that one end of the support member 132 is brought into contact with the lower support surface 114, and the lower end of the support member 132 is pressed to provide the support member 132 accurately. Held in position.

FIG. 4 shows the overall structure of the corona charger 11 shown in FIGS. 2 and 3, in which the plate-shaped electrodes 13 and 131 fixed to the supporting member 132 by the shield plate 14 and the electrode supporting member 112 are disassembled. It is a perspective view shown.

FIG. 5 shows another embodiment of the corona charger 11 of the present invention, and is a cross-sectional view showing a specific structure of the corona charger 11. Similar to FIGS. 2, 3 and 4, the saw-tooth discharge unit 12 for charging the photoconductor 101,
The plate-shaped electrode 13A on which the 121 is formed is made of a stainless steel material having a thickness of about 0.1 mm, is formed by etching, and is the photosensitive member 1 of the photosensitive drum 10 which is the discharged body.
A large number of saw teeth are formed at equal intervals on the side edge facing the image area of No. 01, and are installed so as to face the surface of the photoconductor 101 with a predetermined gap.

In the present embodiment, the plate electrode 13A is formed in a U-shaped cross section, and a plurality of sawtooth discharge parts 12, 121 are formed side by side at the tip edge position in the longitudinal direction.
Further, at both ends, the sawtooth discharge portion 12 of the plate electrode 13A,
Abutting surfaces 137 and 138 are formed on the 121 side, both ends of the plate electrode 13 are provided in the electrode supporting members 111 and 112, and upper supporting surfaces 1131 and 1141 are formed on the electrode supporting members 111 and 112, respectively. ing. A detachable lid member 11 that can be opened to the electrode support members 111 and 112
9 and 120 are provided, and leaf springs S1 and S2 are provided to the lid members 119 and 120.
By attaching 0 to the electrode supporting members 111 and 112, both lower ends of the plate electrode 13A are pressed by the plate springs S1 and S2, and the abutting surfaces 137 and 13 of the sawtooth discharge parts 12 and 121 are pressed.
8 reliably comes into contact with the upper support surfaces 1131 and 1141 to enable accurate positioning.

Further, the electrode supporting members 111 and 112 are shield plates 1 having a U-shaped cross section which is a back plate.
It is fixed to both ends of 4. As a fixing method, fixing with screws is suitable, but fixing with an adhesive or a fitting type may be used. Further, one end of the support member 132 is elastically held by the elastic member 115 provided in the electrode supporting member 111, and the other end is locked by the locking portion 116 provided in the electrode supporting member 112. In addition, the electrode supporting member 1 is provided from one end of the plate electrode 13A.
Conductor 1 between terminals 117 connected to the external power source
Connect at 18.

FIG. 6A is a sectional view taken along the line AA in FIG. 5, in which the lower end of the plate-shaped electrode 13A having a U-shaped cross section is
The lid member 12 fixed to the electrode supporting member 112 as shown in the figure
It is pressed upward by the leaf spring S2 in 0, and the electrode supporting member 11
The abutting surface 138 abuts the upper supporting surface 1141 provided on the No. 2 and the distance between the saw-tooth discharge parts 12 and 121 and the photoconductor 101 is accurately maintained.

FIG. 6B shows a plate electrode 1 in which the plate electrode 13A having a U-shaped cross section shown in FIGS. 5 and 6A has a U-shaped cross section.
3B is shown. The configuration is similar to that shown in FIGS. The plate-shaped electrode 13B having a U-shaped cross section has a plate-shaped electrode 13B.
When pressing a stainless material having a thickness of about 0.1 mm, the processing is easy and so-called drawing cracks do not occur. Both lower ends of the plate electrode 13B are connected to the electrode supporting member 1 as shown in the figure.
S in the lid members 119, 120 fixed to 11, 112
3 and S4, the electrode support members 111 and 11 are pressed upward.
The upper support surface 1141 provided on the second contact surface 137, 138
And the distance between the saw-tooth discharge parts 12 and 121 and the photoconductor 101 is accurately maintained.

FIG. 7 is a perspective view showing the entire structure of the corona charger 11 shown in FIGS. 5 and 6 and showing the plate electrode 13A and the electrode supporting member 112 from the shield plate 14 in an exploded manner.

[0026]

As described above, according to the inventions of claims 1 to 3, by providing a plurality of rows of plate-like electrodes having the sawtooth discharge portion, the additional power to each electrode is reduced, and the power consumption of each electrode is reduced. It is possible to suppress the deterioration and the deposits on the electrodes. Further, since the plate-shaped electrodes are provided in a plurality of rows, it is possible to reduce the influence of the discharge effect due to the contamination of the sawtooth discharge portion. Moreover,
Accurate positioning of the sawtooth electrode portion is possible.

In the second aspect, the plurality of rows of plate electrodes formed of a thin metal plate are fixedly provided on both sides of a supporting member, and both ends of the supporting member are supported by the electrode supporting members. Accurately discharged without bending.

According to the third aspect of the present invention, it is necessary to manufacture a plurality of plate-shaped electrodes by forming a plate-shaped electrode having a U-shaped cross section and forming a plurality of rows of saw-tooth discharge parts at the tip edge position. Since it does not exist, it can be provided at a low price.

According to the present invention, it is necessary to manufacture a plurality of plate-shaped electrodes by forming a plate-shaped electrode having a U-shaped cross section and having a plurality of rows of saw-tooth discharge parts at the tip edge position. Since it is not available, it can be provided at a low price and is easy to process.

[Brief description of drawings]

FIG. 1 is a 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 charger according to the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2 of the present invention.

FIG. 4 is an exploded perspective view showing a corona charger according to the present invention.

FIG. 5 is a sectional view of another corona charger according to the present invention.

6 is a sectional view taken along line AA of FIG. 5 of the present invention.

FIG. 7 is an exploded perspective view showing another corona charger according to the present invention.

[Explanation of symbols]

10 Photosensitive drum 101 photoconductor 11 Corona charger 12,121 Sawtooth discharge part 13, 131, 13A, 13B plate electrodes 14 Shield plate 17 Developer 111, 112 electrode support member 132 Support member

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Koshimura 2970 Ishikawa-cho, Hachioji City, Tokyo Konica Co., Ltd. (56) References JP-A-5-45999 (JP, A) JP-A-6-317974 ( (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 13/02 G03G 15/02

Claims (3)

(57) [Claims] [Claim 1] In the roller <br/> Na charging device of an image forming apparatus to discharge a serrated discharge portion of the plate-shaped electrode to the object to be discharger to face the object discharger, the sawtooth plurality of rows Of the plurality of plates forming the discharge section
An electrode, a support member that supports the plate-shaped electrode, and two support members that support the support member at both ends of the support member.
An electrode supporting member, and forming a supporting surface for supporting the supporting member on the electrode supporting member.
Form, when connecting the external power supply terminals to one of said electrode support member
Together, the electrode supporting member and the supporting member are connected by an elastic member.
A corona charging device for an image forming apparatus, which is characterized in that 2. A saw-tooth discharge portion of a plate electrode is paired with an object to be discharged.
Of the image forming apparatus that discharges the discharged material toward the discharge target
In a charging device, the U-shaped cross section or disconnection that forms the sawtooth discharge parts in multiple rows.
The U-shaped plate electrode and the plate electrode at both ends
It has two electrode supporting members for supporting, and a supporting surface for supporting the plate-shaped electrode is formed on the electrode supporting member.
Form, when connecting the external power supply terminals to one of said electrode support member
Together, the electrode support member and the plate-like electrode are connected by an elastic member.
A corona charging device for an image forming apparatus, which is characterized in that 3. A plate spring, wherein the plate electrode is formed by the plate spring.
By pressing against the supporting surface, the sawtooth discharge part
The corona charging device of the image forming apparatus according to claim 2, wherein the corona charging device is positioned.