JPH09127769A - Corona discharging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corona discharging device where uniform electrification is made by maintaining a corona discharging electrode in a state where it is always cleaned and a stabilizing discharge characteristic, by cleaning the corona discharge electrode by a cleaning member and easily and surely cleaning the corona discharge electrode at the corona discharging device using an integrated type saw-tooth discharging electrode or an independent saw-tooth electrode type discharging electrode. SOLUTION: This device possesses the corona discharge electrode 111 where plural discharge electrodes are linearly formed, a control grid 116 positioned between the corona discharge electrode 111 and an image carrier 10 and controlling the surface potential of the image carrier 10 and plate-like shielded plates 112 positioned on the both sides of the corona discharge electrode 111. In this case, moreover, this device is provided with a cleaning device 30 constituted of the cleaning member 37 cleaning the corona discharge electrode 111 and a driving means moving the cleaning member 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge device for charging the surface of a photoconductor (image forming body) in electrophotographic image formation, and more particularly, to a non-contact type of a plurality of pointed corona discharge devices. The present invention relates to a cleaning device for a corona discharge device having a discharge electrode plate.

[0002]

2. Description of the Related Art In an image forming apparatus for forming an image by an electrophotographic method, a photosensitive member is uniformly charged by a corona discharge type charger, and then imagewise exposed by an imagewise exposing means to form a latent image. Then, after being developed by the developing means to form a toner image, the toner image is transferred onto the recording paper by the transfer device.

Conventionally, corona discharge type chargers used in this type of image forming apparatus are largely classified into a wire discharge type (corotron, scorotron, dicorotron, etc.) and a pin discharge type (pin electrode type, serrated electrode type, etc.). Be separated. The latter has recently come to be used in electrophotographic copying machines, printers and the like due to low ozone generation. In particular, a sawtooth electrode having a structure in which an electrode plate in which a plurality of sawtooth electrode portions are provided on one thin plate member is easy to miniaturize, generates a small amount of ozone, has a low discharge voltage, etc. There is a feature of. A charger using a sawtooth discharge electrode is disclosed in Japanese Patent Laid-Open No. 63-15272.
JP-A-5-45999 and U.S. Pat. S. P.
No. 3,691,373.

As a corona charger using a sawtooth electrode, a charger as shown in FIG. 14 is used. FIG. 14A is a front view showing the configuration of the corona charger, and FIG.
4 (B) is AA of the corona charger shown in FIG. 14 (A).
FIG. In these figures, 111 is a saw-tooth electrode for corona discharge located toward the photoconductor drum 10, and 112 is a shield plate having an opening having a U-shaped cross section. The sawtooth electrode 111 is attached to the shield plate 112 by an insulating electrode plate holding member 113 and a pressing member 114, and the external shape is a hexahedron having a rectangular cross section.

Further, the independent saw-tooth electrode type corona charger in which a high voltage is applied to each of the saw-tooth discharge electrodes via a resistor has a higher ozone generation amount than the above-mentioned saw-tooth electrode type corona charger. Of the sawtooth electrode portions and the variation of the discharge current of each sawtooth electrode portion is reduced.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
There are wire electrodes and sawtooth electrodes. The corona discharge device using the sawtooth electrode is characterized in that it can be easily downsized, the amount of ozone generated is small, and the discharge voltage is low. In addition, the independent sawtooth electrode is characterized in that the amount of ozone generated is further reduced and the variation in the discharge current of each independent sawtooth electrode is reduced as compared with a normal sawtooth electrode. However, since the tips of the integrated sawtooth electrode and the independent sawtooth electrode are sharply and longly projected, they are troublesome to handle and have a drawback that the tip portion is difficult to clean.

Further, when the corona discharge device is used for a long time, foreign matters such as toner and paper powder generated in the periphery adhere to the discharge electrode, causing charging failure and further image failure.

The present invention has been made to solve the above-mentioned problems, and in a corona discharge device using an integrated discharge electrode and an independent sawtooth electrode type discharge electrode, discharge characteristics are stable and uniform charging is performed. Corona discharge that can supply a corona discharge device at low cost, discharge electrodes can be easily cleaned, sufficient discharge can be performed with less discharge current, easy handling and easy assembly and maintenance, corona discharge An object of the present invention is to provide a corona discharge device having features such as downsizing of the device and reduction of ozone generation amount.

[0009]

The above object is to provide a corona discharge electrode in which a plurality of discharge electrodes are linearly formed and a surface potential of the image carrier which is located between the corona discharge electrode and the image carrier. In a corona discharge device having a control grid for controlling the corona discharge electrode and plate-shaped shield plates located on both sides of the corona discharge electrode, a cleaning member for cleaning the corona discharge electrode, and a driving means for moving the cleaning member. It is achieved by a corona discharge device characterized in that it comprises a cleaning device consisting of

In the above invention, the corona discharge device includes four sets of image forming means consisting of a corona discharge device, an image exposure means and a developing device, a transfer means, and a cleaning means in the circumferential direction of a rotating image carrier. And a device for disposing a toner image of different colors by repeatedly charging, exposing and developing the peripheral surface of the image carrier during one rotation of the image carrier to form a color toner image. In a preferred embodiment, the color toner image is mounted on a color image forming apparatus that transfers the color toner image onto a transfer material by a transfer unit.

Further, in the above invention, the corona discharge device includes an image forming means including a corona discharge device, an image exposure means, and a plurality of developing devices, a transfer means, and a cleaning device in a circumferential direction of a rotating image carrier. And a plurality of different color toner images are formed by repeating charging, image exposure and development on the peripheral surface of the image carrier while the image carrier is rotated a plurality of times. In a preferred embodiment, the color toner image is mounted on a color image forming apparatus that transfers the color toner image onto a transfer material by a transfer unit.

[0012]

1 is a block diagram showing an example of a color image forming apparatus suitably equipped with a corona discharge device of the present invention. In the figure, reference numeral 10 denotes a drum-shaped image bearing member, that is, a photosensitive drum, and a transparent conductive layer, an organic photosensitive member (OPC) or a on the outer periphery of a cylindrical substrate formed of a transparent member such as optical glass or transparent acrylic resin. A photosensitive layer made of —Si or the like is provided.

The photosensitive drum 10 is bearing-supported by a flange guide pin at one end, and the flange at the other end is externally fitted to a plurality of guide rollers provided on the substrate of the main body of the apparatus to drive the outer peripheral gear. , And is rotated clockwise with the driving force thereof grounding the transparent conductive layer.

Reference numerals 11Y, 11M, 11C and 11K are corona chargers used in the image forming process of each color of yellow (Y), magenta (M), cyan (C) and black (K). The above-mentioned organic photoreceptor layer is charged by the grid held at a predetermined potential and the corona discharge by the electrode plate to give a uniform potential to the photoreceptor drum 10.

12Y, 12M, 12C and 12K are LEDs, FL, EL arranged in the axial direction of the photosensitive drum 10.
An exposure optical system including a light emitting element such as a PL and an image forming element such as a SELFOC lens, in which image signals of respective colors read by a separate image reading device are sequentially taken out from a memory and each of the exposure optical systems described above. System 12Y, 12M, 12
The electric signals are input to C and 12K, respectively.

Each of the above-mentioned exposure optical systems 12Y, 12M, 12
Both C and 12K are attached to a cylindrical support member 120 fixed to the substrate of the apparatus main body with guide pins as guides, and are housed inside the base body of the photosensitive drum 10. The exposure optical system 12 includes an LCD, LIS and the above light emitting element.
A combination of optical shutter members such as A and PLZT and an imaging element such as a SELFOC lens can also be used.

Reference numerals 13Y, 13M, 13C and 13K denote developing units which are developing means for accommodating each of yellow (Y), magenta (M), cyan (C) and black (K) developers.
The developing sleeves 130 rotate in the same direction while maintaining a predetermined gap with respect to the peripheral surface of the photoconductor drum 10.

The developing devices 13Y, 13M, 13C and 13K are the corona chargers 11Y, 11M and 1 described above.
1C and 11K charging and exposure optical systems 12Y and 12
The electrostatic latent image formed on the photosensitive drum 10 by image exposure with M, 12C, and 12K is subjected to reversal development by a non-contact development method under application of a development bias voltage.

In the image reading apparatus which is separate from this apparatus, the original image is an image read by the image pickup device or an image edited by a computer is once used as an image signal for each color of Y, M, C and K. Stored and stored in memory.

In forming an image, the photoconductor drum 1 is started by starting the photoconductor drive motor by starting the image recording.
0 is rotated clockwise, and at the same time, application of electric potential to the photoconductor drum 10 is started by the charging action of the corona charger 11Y.

After a potential is applied to the photosensitive layer of the photosensitive drum 10, the exposure optical system 12Y starts image exposure with an electric signal corresponding to a first color signal, that is, a yellow (Y) image signal, and the drum is started. An electrostatic latent image corresponding to the yellow (Y) image of the original image is formed on the photosensitive layer on the surface by the rotational scanning of.

The latent image is reversely developed by the developing device 13Y in a state where the developer on the developing sleeve is not in contact with the latent image, and a yellow (Y) toner image is formed according to the rotation of the photosensitive drum 10.

Then, the photosensitive drum 10 is further given a potential on the yellow (Y) toner image by the discharging action of the corona charger 11M, and the second image of the exposure optical system 12M.
Image signal is applied by an electric signal corresponding to the color signal of (1), that is, the image signal of magenta (M), and the non-contact reversal development by the developing device 13M causes the magenta (M) toner image on the yellow (Y) toner image. The toner images are sequentially superposed and formed.

By the same process, the corona charger 11
C, the exposure optical system 12C, and the developing device 13C further produce a cyan (C) toner image corresponding to the third color signal,
Finally, a black (K) toner image corresponding to the fourth color signal is sequentially formed by the corona charger 11K, the exposure optical system 12K, and the developer 13K, and the black (K) toner image is formed within one rotation of the photosensitive drum 10. A color toner image is formed on the peripheral surface.

These exposure optical systems 12 (Y, M, C,
The image exposure of the photosensitive layer of the photosensitive drum 10 by K) is performed from the inside of the drum through the transparent substrate. Therefore, the exposure of the image corresponding to the second, third, and fourth color signals is performed in a state in which none of the toner images previously formed is transmitted, and is equivalent to the image corresponding to the first color signal. It is possible to form an electrostatic latent image of. In order to stabilize the temperature inside the photoconductor drum 10 and prevent the temperature rise due to the heat generation of each exposure optical system 12 (Y, M, C, K), a material having good thermal conductivity is used for the support member 120. When the temperature is low, a heater is used, and when the temperature is high, heat is radiated to the outside through a heat pipe. Further, during the developing action by each developing device, a developing bias voltage in which a direct current or an alternating current is applied to the developing sleeve is applied respectively, and jumping development is performed by the one-component or two-component developer accommodated in the developing device, thereby making it transparent. Non-contact reversal development is performed on the photoconductor drum 10 whose grounding is the conductive layer.

The above-mentioned photosensitive drum 10 and corona charger 1
1 (Y, M, C, K), exposure optical system 12 (Y, M, C,
K), the developing device 13 (Y, M, C, K) and the cleaning device 19 are housed in a detachable housing in the main body of the image forming apparatus to form the process cartridge 100.

The color toner image thus formed on the peripheral surface of the photosensitive drum 10 is conveyed from the paper feeding cassette 15 in the corona transfer device 14A having a transfer electrode and is fed in synchronization with the driving of the timing roller 16. Is transferred onto a transfer paper which is a transfer material.

The transfer paper on which the toner image has been transferred is separated from the peripheral surface of the photoconductor drum by removing the charge in the corona charge-eliminating separator 14B having a separation electrode, and is fixed by the fixing device 17.
After the toner is welded, the toner is discharged onto the tray 20 at the upper part of the apparatus through the paper discharge roller 18.

Hereinafter, the corona charger 11 (Y, M,
C, K), corona transfer device 14A, corona charge removal separator 14
B is generically called a corona discharge device.

On the other hand, the photosensitive drum 10 from which the transfer paper is separated
The cleaning device 19 removes and cleans residual toner to continue forming the toner image of the original image, or temporarily stops and waits for formation of a new toner image of the original image.

FIG. 2 is an enlarged sectional view showing a part of the image forming apparatus of FIG. A plurality of developing devices 13Y, 13M,
13C shows a plurality of corona chargers 11Y, 11M, 11C and 11K arranged adjacent to 13C and 13K. Since these corona chargers 11Y, 11M, 11C, and 11K have the same structure, the corona chargers will be hereinafter referred to as the corona charger 11 as a representative. FIG. 3 is a front view of the corona charger 11.

2 and 3, reference numeral 111 denotes a sawtooth electrode which is an example of a corona discharge electrode, which will be described in detail with reference to FIG. 112
Is a shield plate having an opening, and the photosensitive drum 1
An opening is provided substantially parallel to the 0 circumferential surface. The shield plate 112 is, for example, a stainless steel shield plate.

The sawtooth electrode 111 is attached to an electrode plate holding member 113 made of an insulating resin, and is pressed by a pressing member 114 also made of an insulating resin, and then both ends are made of an insulating resin, for example, ABS resin. It is sandwiched by the front and rear side members 115, dropped into the shield plate 112, and the electrode plate holding member 113 having the sawtooth electrode 111, the pressing member 114, and the side member 115 are integrally fixed to the shield plate 112 by a resin screw.

On the opening side of the shield plate 112,
For example, a control electrode (control grid) 116 formed by etching a stainless steel plate having a thickness of 0.1 mm to have a mesh width of 1 mm is attached to the side member 115 with a resin screw for attaching the control electrode, and a scorotron type corona charging is performed. The vessel 11 is assembled. The width of the opening generally affects the charging performance, and the wider the opening, the better the charging performance. The slower the linear velocity (peripheral velocity) of the photosensitive drum 10, the more advantageous for charging. Although the width of the opening is determined depending on the image forming apparatus, in the image forming apparatus having the corona charger of the present invention, the peripheral space of the photoconductor drum 10 is effectively used and the image processing unit such as the image exposure device or the developing device is used. In order to obtain a small-sized image forming apparatus which has not been used in the past by properly arranging the above, corona chargers 11Y, 11M, 11C, 1
1K has a narrow and flat configuration. However, because of this, the gap between the shield plates 112 is narrowed, and the sawtooth electrode 11
1 to the side plate of the shield plate 112 and the control electrode 116
There is a problem in that an excessive overcurrent flows to the device and proper and uniform charging characteristics cannot be obtained.

The present invention is intended to obtain appropriate and uniform charging characteristics even for such a narrow and flat corona discharge device.

FIG. 4A shows a sawtooth electrode 111 according to the present invention.
4 is a perspective view of a sawtooth electrode plate 70 including the insulating substrate 117 and an insulating substrate 117. FIG. 4B is a side sectional view of the sawtooth electrode plate 70.
(C) is a front view of the sawtooth electrode plate 70. The sawtooth electrode plate 70 provided on the corona charger 11 shown in these figures is formed by integrally forming the sawtooth electrode 111 on the insulating substrate 117 by means such as vapor deposition or etching. Alternatively, the sawtooth electrode 111 made of a conductive thin plate such as a stainless steel plate is bonded to the insulating substrate 117 to be formed.
A tip portion in which a plurality of pointed heads 111a, which are the tip ends of electrodes having the same length, are linearly arranged at a constant pitch is positioned to face the circumferential surface of the photosensitive drum 10. Sawtooth electrode 1 of sawtooth electrode plate 70
No. 11 has a pitch p of the tip 111a of 2 mm, a peak height h of 2 mm, a peak apex angle θ of 15 °, and a peak radius r of 20 μm or less. is there.
Adjacent peaks 111a, 111 of the sawtooth electrode 111
If the pitch p between a is too close, a discharge current will flow and the discharge will become unstable. Therefore, the pitch p requires a certain distance. As a result of various studies, this pitch p is required to be 2 mm or more for stabilizing the discharge. The sawtooth electrode 111 is 4 to
It is connected to a power supply 110 that applies a high voltage of 10 kV.

The pointed portion 111a of the saw-toothed electrode 111 facing the control electrode 116 is arranged in parallel with a position slightly retracted from the tip portion 117a of the insulating substrate 117.

The insulating substrate 117 is made of a material such as a ceramic plate, a glass plate or an epoxy resin plate which does not cause dielectric breakdown even when a high voltage is applied.

The point 111 of the sawtooth electrode 111 is formed on the surface of the sawtooth electrode 70 opposite to the insulating substrate 117.
You may coat the part except a with the insulating coating member 118. In addition, the sawtooth electrode 1 facing the control electrode 116
The eleven pointed head portions 111a are arranged in parallel with each other at a position slightly retracted from the tip portion 117a of the insulating substrate 117.

The insulating substrate 117 and the sawtooth electrode 11
1. By arranging the insulating coating member 118 in this manner, handling at the time of maintenance, inspection, and repair of the corona charger becomes easier, and the pointed head 111a of the sawtooth electrode 111 is less likely to get dirty, so that it can be used for a long time. The effects such as stable discharge performance, easy cleaning of the pointed portion 111a of the sawtooth electrode 111, and miniaturization of the corona charger 11 are exhibited.

FIG. 5 is a front view of a discharge electrode portion in which a plurality of independent sawtooth electrodes 119 are arranged. Multiple independent sawtooth electrodes 1
19 are arranged in parallel on the insulating substrate 117, and are covered with an insulating covering member 118 except the pointed head 119a which is the discharge acting portion of the independent sawtooth electrode 119. Each of the plurality of independent sawtooth electrodes 119 is connected to the power source 110 via an electric resistance R. The pointed portions 119a of the plurality of independent sawtooth electrodes 119 facing the control electrodes 116 have the insulating substrate 117K.
Are arranged in parallel with each other at a position slightly retracted from the front end portion 117a.

However, even in the corona charger having the sawtooth electrode 111 or the independent sawtooth electrode held on the insulating substrate 117 as described above, there is a problem that it is difficult to clean the tip portion.

FIG. 6A is a sectional view showing an embodiment of the corona charger 11 equipped with the cleaning device 30 according to the present invention, and FIG. 6B is a sectional view taken along the line AA. In addition,
Although the figure shows an integral sawtooth electrode 70, the independent sawtooth electrode 1
The present invention is also applicable to 19. Hereinafter, the cleaning device and the driving means will be described.

At the outermost ends of the corona charger 11 in the longitudinal direction, a pair of left and right fixed side plates 31 and 32 are fixed to the main body of the image forming apparatus or the housing of the process unit 100 and face each other in parallel. A fixed guide bar 33 and a rotatable feed screw 34 are fixed in parallel between the fixed side plates 31 and 32. The feed screw (screw bar) 34 is driven and rotated by a motor 35, which is a drive source, via a transmission means (not shown). The lead screw 34
Makes the carriage member 36 movable. That is,
The carriage member 36 is configured such that the female screw portion at the substantially central portion of the carriage member 36 is screwed into the feed screw 34 and the bearing bar at one end of the carriage member 36 is fitted with the guide bar 33. , The fixed side plate 3 by the feed screw 34 and the guide bar 33 which rotate in the forward and reverse directions.
Moves straight between 1 and 32.

A cleaning member (cleaning pad) 37 is attached below the carriage member 36 and on the surface facing the sawtooth electrode 70. The cleaning pad 37 includes the surface of the sawtooth electrode 70 and the pointed portion 11.
1a and the tip portion 117a of the insulating substrate 117 by pressure contact,
Each of these parts is cleaned by the reciprocating movement of the carriage member 36. This cleaning operation is performed during warming up after the power of the image forming apparatus main body is turned on. When the cleaning operation is not performed, the carriage member 36 is located outside the latent image forming area of the photosensitive drum 10.

FIG. 7A is a sectional view showing another embodiment of the corona charger 11 having the cleaning device 40 according to the present invention, and FIG. 7B is a sectional view taken along the line AA.

At the outermost ends of the corona charger 11 in the longitudinal direction, a pair of left and right fixed side plates 41 and 42 are fixed to the main body of the image forming apparatus or the housing of the process unit 100 and face each other in parallel. A holder member 46 is supported between the fixed side plates 41 and 42 via a ball bearing 43 so as to be vertically movable. A female screw portion provided near the center of the holder member 46 in the left-right direction is driven and rotated by a motor 45, which is a drive source, via a transmission means. The rotatable feed screw 34 and the pair of left and right fixed side plates 41, 42 are arranged in parallel. The feed screw 44 allows the movable holder member 46 to move. That is, the female screw portion at the substantially central portion of the movable holder member 46 is screwed into the feed screw 44, and both end portions of the movable holder member 46 have a pair of left and right fixed side plates 41, 42.
The movable holder member 46 is linearly and reciprocally moved along the fixed side plates 41 and 42 by the feed screw 44 which is rotated forward and backward.

A cleaning member (cleaning pad) 47 is attached to the surface of the movable holder member 46 facing the sawtooth electrode 111. The cleaning pad 47 includes the surface of the sawtooth electrode 70 and the pointed portion 111a.
Then, the movable holder member 46 is reciprocally moved to clean these parts. This cleaning operation is performed during warming up after the power of the image forming apparatus main body is turned on. When the cleaning operation is not performed, the movable holder member 46 is moved to the pointed portion 1 of the sawtooth electrode 70.
It is located on the opposite side of 11a.

FIG. 8 is a sectional view showing various embodiments of the cleaning member. In FIG. 8A, a cleaning pad 47 having an elastic member such as felt or foamed plastic is attached as a cleaning member to the surface of the movable holder member 46. FIG. 8B shows a cleaning member having a structure in which a cleaning pad 47 made of felt or foamed plastic is attached to the surface of the holder member 46, and a cleaning web 48 made of nonwoven fabric or the like is further laminated on the surface. This structure prevents the felt or the surface layer of the foamed plastic from falling off, has excellent abrasion resistance, and enables maintenance of cleaning performance for a long period of time. FIG.
In (C), a cleaning brush 49 in which flocking is provided instead of the cleaning pad 47 is provided on the surface of the holder member 46, and the same effect can be obtained. The various embodiments of the cleaning member described above are also applicable to the cleaning pad 37 shown in FIG.

FIG. 9A shows the corona charger 2
Of the sawtooth electrodes 111 (or the independent sawtooth electrodes 11)
9) is a cross-sectional view of the corona charger formed in parallel on both sides of the insulating substrate 117. FIG. 9 (B) is a front view of an electrode portion composed of two sawtooth electrodes (111A, 111B) and an insulating substrate 117D, and FIG. 9 (C) is an AA of the electrode portion.
It is sectional drawing. In the insulating substrate 117 of this embodiment, if the sawtooth electrodes 111A and 111B are arranged in parallel and the phases of the sawtooth electrodes 111A and 111B are shifted by a half pitch as shown in FIG. 9C, the sawtooth electrodes are arranged. 111A, 1
If the distance W between the pointed portions 111a and 111b of 11B is set to a constant distance, the distance D between the sawtooth electrodes 111A and 111B can be narrowed.

FIG. 10A shows a cleaning device (5 mounted on a corona charger composed of two sawtooth electrodes 111A and 111B arranged in parallel on both sides of the insulating substrate 118.
0) is a sectional view showing the embodiment of FIG.
It is A sectional drawing.

At the outermost ends of the corona charger 11 in the longitudinal direction, a pair of left and right fixed side plates 51 and 52 are fixed to the main body of the image forming apparatus or the housing of the process unit 100 and face each other in parallel. A fixed guide bar 53 and a rotatable feed screw 54 are fixed in parallel between the fixed side plates 51 and 52. The feed screw (screw bar) 54 is driven and rotated by a motor 55, which is a drive source, via a transmission means (not shown). The lead screw 54
Makes the carriage member 56 movable. That is,
The carriage member 56 has a U shape, an internal thread portion formed at one upper end is screwed to the feed screw 54, and a bearing portion formed at the other upper end of the carriage member 56 has the guide bar 53. The carriage member 56 has the fixed side plates 51, 52 by the feed screw 54 and the guide bar 53, which rotate forward and reverse.
Move straight ahead and back.

Below the carriage member 56, a U-shaped cleaning pad 57 is attached to the inner surface facing the sawtooth electrodes 111A and 111B. The cleaning pad 57 includes the sawtooth electrodes 111A, 1A.
The carriage member 5 is pressed against the surface of 11B, the pointed portions 111a and 111b, and the tip portion 118a of the insulating substrate 118.
Each of these parts is cleaned by the reciprocating movement of 6. This cleaning operation is performed during warming up after the power of the image forming apparatus main body is turned on. When the cleaning operation is not performed, the carriage member 56 is located outside the latent image forming area of the photosensitive drum 10.

FIG. 11 (A) is a sectional view showing another embodiment of the cleaning device (60) mounted on the corona charger according to the present invention, and FIG. 11 (B) is its AA sectional view. .

At the outermost ends of the corona charger 11 in the longitudinal direction, a pair of left and right fixed side plates 61, 62 are fixed to the main body of the image forming apparatus or the housing of the process unit 100 and face each other in parallel. A movable holder member 66 is supported between the fixed side plates 61 and 62 via a ball bearing 63 so as to be able to move straight in the vertical direction. A female screw portion provided near the center in the left-right direction of the movable holder member 66 is driven and rotated by a motor 65, which is a drive source, via a transmission means. The rotatable feed screw 64 and the pair of left and right fixed side plates 61, 62 are arranged in parallel. The feed screw 64 makes the movable holder member 66 movable. That is, the female screw portion at the substantially central portion of the movable holder member 66 is screwed into the feed screw 64, and both end portions of the movable holder member 66 have a pair of left and right fixed side plates 6.
With the configuration in which the movable holder member 66 is guided by the guide screws 1, 62, the movable holder member 66 can rotate forward and reverse.
As a result, it moves straight forward and backward along the fixed side plates 61, 62. The movable holder member 66 is formed in a frame shape, and the two outer peripheral surfaces slide on the inner surface of the shield plate 112.
Cleaning pads 67A and 67B are attached to the two inner surfaces. The cleaning pad 67A is in pressure contact with the surface of the sawtooth electrode 111A and the pointed tip 111a, and the cleaning pad 67BA is in pressure contact with the surface of the sawtooth electrode 111B and the pointed tip 111b. Movable holder member 66
By the reciprocating movement of the two sawtooth electrodes 111A, 111B
Each of the above parts is simultaneously cleaned by the cleaning pads 67A and 67B. This cleaning operation is performed during warming up after the power of the image forming apparatus main body is turned on. When the cleaning operation is not performed, the movable holder member 66 is moved to the sawtooth electrodes 111A and 11A.
It is located on the opposite side of the pointed heads 111a and 111b of 1B.

Since the exposure optical system is provided inside the photosensitive drum in the image forming apparatus of the embodiment shown in FIG. 1, the adjoining member of the corona discharge device is the cleaning means, pre-charging exposure means or There is a developing means. In the image forming apparatus in which the exposure optical system is provided on the outer side of the photoconductor drum, there are other exposing means such as cleaning means, pre-charging exposure means, and developing means as adjacent members, so that the external shape can be freely set. By using the corona discharge device of the invention, a space is effectively used and a compact image forming apparatus is provided.

Further, the corona discharge device of the present invention is not limited to the corona charger 11 described above, but can be applied to the corona transfer device 14A and the corona charge removal separator 14B.

FIG. 12 is a block diagram showing another embodiment of the image forming apparatus having the corona discharge device of the present invention. In the figure, parts having the same functions as those in FIG. 1 of the above embodiment are designated by the same reference numerals. Further, points different from the above embodiment will be described.

Reference numeral 101 denotes a belt-shaped image bearing member, a so-called photosensitive belt, which is formed by coating an organic photosensitive layer (OPC) on the outer periphery of a flexible endless substrate, and is horizontally arranged between the rotary roller and the roller. In the state of being stretched around, it is circulated and conveyed in the clockwise direction in the drawing by the drive of the rotating roller.

The photoconductor belt 101 forms an image forming surface by rubbing the peripheral surface below the photoconductor belt 101 against the guide member 102 by the bias of the tension roller.

Reference numerals 11Y, 11M, 11C and 11K are scorotron charging type corona chargers, and are provided on the photosensitive belt 101.
The above-mentioned organic photosensitive layer is charged by a corona discharge by a control electrode (grid) and a sawtooth electrode held at a predetermined potential to give a uniform potential to the photosensitive belt 101.

12Y, 12M, 12C and 12K are FL, EL, PL, LEDs in which light emitting elements are arranged in a line in the depth direction of the photoconductor belt 101, or LISA, PLZT in which elements having an optical shutter function are arranged in parallel. An exposure optical system composed of an LCS and a SELFOC lens as a unity-magnification imaging element, in which image signals of respective colors read by a separate image reading device are sequentially taken out from a memory to be supplied to the respective exposure optical systems. Each is input as an electric signal.

13Y, 13M, 13C and 13K are developing units for accommodating yellow (Y), magenta (M), cyan (C) and black (K) developers, respectively. On the other hand, a developing sleeve is provided which rotates in the same direction while maintaining a predetermined gap. Each developing device 13
(Y, M, C, K) is the corona charger 11 described above.
(Y, M, C, K) charging and exposure optical system 12 (Y,
The electrostatic latent image formed on the photosensitive belt 101 by image exposure with M, C, K) is reversely developed in a non-contact state by applying a developing bias voltage.

In the above-mentioned color image forming apparatus, the corona charger 11, the exposure optical system 12, and the developing device 13 constitute one set of a single color, and four sets of these sets are arranged in series. The corona chargers 11Y, 11M, 11C and 11K are also shown in FIG.
A plurality of columns are arranged in parallel as shown below. As a result, corona charging can be made uniform and stable, and sufficient charging can be performed with a smaller discharge current.

FIG. 13 is a constitutional view showing still another embodiment of the image forming apparatus having the corona discharge device of the present invention. In the figure, parts having the same functions as those in FIG. 1 of the above embodiment are designated by the same reference numerals. Further, points different from the above embodiment will be described.

The image forming apparatus comprises a rotating image carrier 10
In the circumferential direction, an image forming unit including a corona charger 11, an image exposure unit 12, a plurality of developing units 13Y, 13M, 13C, and 13K, a corona transfer unit 14A, and a corona charge removal separator 1
4B and the cleaning device 19 are provided, and the image carrier 1
During a plurality of rotations of 0, charging, image exposure and development are repeated on the peripheral surface of the image carrier 10 to form different color toner images so as to form a color toner image, and the color toner image is transferred to the corona transfer device 14A. The transfer material is transferred to a transfer material by a corona discharge separator 14B, and the transfer material is separated from the image carrier 10 by a corona charge-eliminating separator 14B. To be discharged to. A corona charger 11 and a corona transfer device 1 which are mounted on this image forming apparatus and serve as a corona discharge device.
The present invention is also applicable to 4A and corona charge removal separator 14B.

[0067]

The corona discharge device of the present invention is a corona discharge device using an integrated sawtooth discharge electrode or an independent sawtooth electrode type discharge electrode, in which a thin corona discharge electrode is held on an insulating substrate. Since the electrode is cleaned by the reciprocating movement of the cleaning member, the corona discharge electrode can be easily and surely cleaned. Therefore, a corona discharge device is provided in which the corona discharge electrode is always maintained in a clean state, discharge characteristics are stable, and uniform charging is performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an image forming apparatus having a corona discharge device of the present invention.

FIG. 2 is a partially enlarged sectional view of the image forming apparatus shown in FIG.

FIG. 3 is a front view of the corona charger shown in FIG.

FIG. 4 is a perspective view, a side view, and a front view showing an embodiment of a sawtooth electrode of a corona charger used in the present invention.

FIG. 5 is a front view showing an embodiment of an independent sawtooth electrode used in the present invention.

6A and 6B are a sectional view and a front view showing an embodiment of a corona charger including a cleaning device according to the present invention.

7A and 7B are a sectional view and a front view showing another embodiment of a corona charger including a cleaning device according to the present invention.

FIG. 8 is a sectional view of various cleaning members according to the present invention.

FIG. 9 is a cross-sectional view of a corona charger including an electrode unit in which two saw-tooth electrodes are arranged in parallel, a front view of the electrode unit, and a cross-sectional view taken along line AA.

10A and 10B are a sectional view and a front view showing an embodiment of a cleaning device provided in the corona charger.

11A and 11B are a cross-sectional view and an AA cross-sectional view showing another embodiment of the cleaning device provided in the corona charger.

FIG. 12 is a configuration diagram showing another embodiment of the image forming apparatus provided with the corona discharge device of the present invention.

FIG. 13 is a configuration diagram showing still another embodiment of the image forming apparatus provided with the corona discharge device of the present invention.

FIG. 14 is a configuration diagram of a corona discharge device having a conventional sawtooth electrode.

[Explanation of symbols]

10 Photoconductor drum (image carrier) 100 Process unit 101 Photoconductor belt (image carrier) 11, 11Y, 11M, 11C, 11K Corona chargers 111, 111A, 111B Sawtooth electrodes (corona discharge electrodes) 111a, 111b, 119a , 119b Sharp head 112 Shield plate 113 Electrode plate holding member 114 Holding member 116 Control grid 117, 118 Insulating substrate 119 Independent sawtooth electrode (corona discharge electrode) 12Y, 12M, 12C, 12K Exposure optical system 13Y, 13M, 13C, 13K Developing device 14A Corona transfer device 14B Corona charge removing separator 30, 40, 50, 60 Cleaning device 31, 31, 41, 42, 51, 52, 61, 62 Fixed side plate 33, 53 Guide bar 34, 44, 54, 64 Feed screw 35, 45, 55, 65 Motor 36,56 Carriage member 37,47,57,67 Cleaning pad (cleaning member) 46,66 Movable holder member 48 Cleaning web (nonwoven fabric, cleaning member) 49 Cleaning brush (cleaning member) 70 Sawtooth electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Komatsu 2970 Ishikawa-cho, Hachioji, Tokyo Konica stock company (72) Inventor Satoshi Haneda 2970 Ishikawa-cho, Hachioji, Tokyo Konica stock company

Claims (13)

[Claims] 1. A corona discharge electrode in which a plurality of discharge electrodes are linearly formed, a control grid which is located between the corona discharge electrode and the image carrier, and which controls a surface potential of the image carrier, A corona discharge device having plate-shaped shield plates located on both sides of a corona discharge electrode, comprising a cleaning device comprising a cleaning member for cleaning the corona discharge electrode and a drive means for moving the cleaning member. A corona discharge device characterized in that 2. The corona discharge device according to claim 1, wherein the driving means moves the cleaning member in a direction in which a plurality of discharge electrodes formed in a linear shape of the corona discharge electrode are arranged. . 3. The driving means is capable of moving the cleaning member in a direction orthogonal to a direction in which a plurality of linearly-formed discharge electrodes for the corona discharge electrode are arranged. Corona discharge device. 4. The corona discharge device according to claim 1, wherein the cleaning member is a cleaning pad having elasticity. 5. The corona discharge according to claim 1, wherein the cleaning member is a laminated member including a cleaning pad having elasticity and a sheet member having abrasion resistance. apparatus. 6. The corona discharge device according to claim 1, wherein the cleaning member is a cleaning brush having elasticity. 7. The corona discharge device according to claim 1, wherein the corona discharge electrode is a sawtooth electrode integrally formed by linearly arranging a plurality of sawtooth cusps. 8. The corona discharge electrode is a corona discharge electrode formed by arranging a plurality of independent discharge electrode plates each having a serrated point in a straight line. 1. The corona discharge device according to 1. 9. The corona discharge device according to claim 1, wherein the corona discharge electrode is in close contact with an insulating substrate. 10. The corona discharge electrode facing the image carrier is provided at a position where the tip of the corona discharge electrode does not protrude from the tip of the insulating substrate.
8. The corona discharge device according to any one of 8. 11. The corona according to claim 1, wherein the corona discharge electrode is a plurality of electrode plates respectively formed on both sides of an insulating substrate. Discharge device. 12. The corona discharge device includes four sets of image forming means including a corona discharge device, an image exposure means, and a developing device, a transfer means, and a cleaning device in a circumferential direction of a rotating image carrier. When the image carrier is rotated once, the peripheral surface of the image carrier is repeatedly charged, image-exposed and developed to form toner images of different colors, thereby forming a color toner image. The corona discharge device according to claim 1, wherein the corona discharge device is mounted on a color image forming apparatus that transfers to a transfer material by a transfer unit. 13. The corona discharge device is provided with a corona discharge device, an image exposure unit, an image forming unit including a plurality of developing units, a transfer unit, and a cleaning unit in the circumferential direction of a rotating image carrier. Then, while rotating the image carrier a plurality of times,
A color image forming apparatus for forming a color toner image by superposing different color toner images by repeating charging, image exposure and development on the peripheral surface of an image carrier and transferring the color toner image to a transfer material by a transfer means. The corona discharge device according to claim 1, which is mounted.