JP5327571B2 - Scorotron charging device, image forming apparatus and process cartridge - Google Patents

Description

  The present invention relates to a scorotron charging device used in an image forming apparatus such as a printer, a facsimile machine, and a copying machine, an image forming apparatus including the scorotron charging device, and a process cartridge.

  2. Description of the Related Art Conventionally, in an image forming apparatus, as a means for uniformly charging the surface of a photoconductor, a charge wire disposed in a shield case at a predetermined interval on the surface of the photoconductor is disposed closer to the photoconductor than the charge wire. A scorotron charging device having a grid electrode is known. The scorotron charging device generates corona discharge by applying a high voltage to the charge wire, and can charge the surface of the photosensitive member at substantially the same potential as the grid electrode.

  If the grid electrode is contaminated with toner, discharge products, paper dust, etc. over time, the charging performance is lowered. If the uniformity of charging cannot be ensured due to this contamination, the photosensitive member cannot be uniformly charged, resulting in unevenness in the output image. Therefore, many scorotron charging devices are provided with cleaning means for cleaning the grid electrodes.

  In general, the scorotron charging device is replaced after a certain number of outputs for maintenance, but it is possible to extend the life of the scorotron charging device by removing contamination such as grid electrodes by the cleaning means. Therefore, it is very important to clean the grid electrode by the cleaning means from the viewpoints of economy and environment.

  Here, since the grid electrode is pushed by the cleaning member at the position where the cleaning member is in contact with the grid electrode, the distance between the contact area and the surrounding grid electrode and the photoconductor is different from the predetermined distance. If the cleaning member is in contact with the grid electrode at the time of image formation, the distance between the contact portion and the surrounding grid electrode and the photosensitive member is different from the predetermined interval, so that the photosensitive member can be made uniform with an appropriate charging potential. It becomes impossible to charge, and uneven charging occurs on the photoreceptor.

  Japanese Patent Application Laid-Open No. H10-228688 discloses a device that separates the cleaning member from the grid electrode during non-cleaning by a posture changing means such as a cam. Thus, by separating the cleaning member from the grid electrode at the time of non-cleaning, the grid electrode is not pushed by the cleaning member, and the interval between the grid electrode and the photoconductor can be maintained at a predetermined interval. Therefore, it is possible to suppress uneven charging that may occur when the interval is smaller than the predetermined interval.

JP 2007-139860 A

  However, in the configuration in which the cleaning member is separated from the grid electrode using the posture changing means such as a cam described in Patent Document 1, the mechanism for separating the cleaning member from the grid electrode becomes complicated, so that the cost can be reduced. There arises a problem that it is not suitable for downsizing of the apparatus.

  The present invention has been made in view of the above problems, and the object of the present invention is that the cleaning member can be separated from the grid electrode without providing a complicated separation mechanism. It is to provide a possible scorotron charging device.

In order to achieve the above object, the invention of claim 1 includes a shield case having a discharge opening, a discharge electrode disposed in the shield case, and a grid electrode stretched in the discharge opening. A scorotron charging device including a cleaning member that moves in a longitudinal direction of the grid electrode and cleans the grid electrode by rubbing against the grid electrode, wherein the cleaning member does not clean the grid electrode A cover member that covers the surface of the grid electrode facing the cleaning member is provided at a standby position provided in a predetermined region of the grid electrode, which sometimes causes the cleaning member to wait. The distance from the surface on the opposite side to the surface on the opposite side of the surface facing the grid electrode of the cover member is determined by the movement of the cleaning member in the longitudinal direction. From off-site of the grid electrode on the distance that can be riding on the cover member, the cleaning member is foamed polyurethane, the cleaning member is held by a cleaning member holding member movable in the longitudinal direction, When the natural length of the thickness of the cleaning member is A, the thickness of the cleaning member when it is on the grid electrode is B, and the thickness of the cleaning member when it is on the cover member is C, The compression ratio (A-B) / A of the cleaning member when it is in the range of 0.4 or more, and the compression ratio (A-C) / A of the cleaning member when it is on the cover member is 0.64 In the following, the configuration is as follows.
According to a second aspect of the present invention, in the scorotron charging device according to the first aspect, the cover member is in the form of a sheet.
According to a third aspect of the present invention, in the scorotron charging device according to the first or second aspect, the grid electrode and the cover member have an arc shape.
According to a fourth aspect of the present invention, in the scorotron charging device of the third aspect, the cover member is previously processed into an arc shape.
The invention of claim 5 is the image forming apparatus including an image bearing member, and charging means allowed to charge a surface of the image bearing member, as the charging means, a scorotron according to claim 1, 2, 3 or 4 A charging device is used.
According to a sixth aspect of the present invention, there is provided a process cartridge detachably attached to an image forming apparatus, in which a charging unit and at least one of an image carrier, a developing unit, and a cleaning unit are integrally formed. The scorotron charging device according to claim 1, 2, 3 or 4 is used.
According to a seventh aspect of the present invention, there is provided an image forming apparatus comprising a process cartridge that is configured integrally with a charging unit and at least one of an image carrier, a developing unit, and a cleaning unit, and is detachable from the apparatus main body. As the process cartridge, the process cartridge according to claim 6 is provided.

  In the present invention, the cleaning member can run on the cover member provided at the standby location from the grid electrode outside the standby location by moving the cleaning member in the longitudinal direction. Accordingly, the cleaning member can be separated from the grid electrode by moving the cleaning member to the standby position and riding on the cover member during non-cleaning. Therefore, the cleaning member can be separated from the grid electrode during non-cleaning without providing a complicated separation mechanism.

  As described above, according to the present invention, there is an excellent effect that the cleaning member can be separated from the grid electrode without providing a complicated separation mechanism, and the cost and size can be reduced.

  The best mode for carrying out the present invention will be described below with reference to the drawings. However, this is only an embodiment and does not limit the scope of the present invention.

  FIG. 2 is a diagram showing a schematic configuration of the image forming apparatus according to the present invention. Here, a full-color copying machine (hereinafter simply referred to as a copying machine) 100 will be described as an example. The copying machine 100 includes an image forming unit 300, a paper feeding unit 200, a document reading unit 400, and a document conveying unit 500. The image forming unit 300 includes an image forming unit 10, an exposure device 3, a transfer device 5, and a fixing device 7.

  The image forming unit 10 includes three process cartridges 10C that form toner images of three colors of yellow (Y), cyan (C), and magenta (M), and a process cartridge 10K that forms a toner image of black (K) in parallel. Prepare. Photosensitive members 1Y, 1C, 1M, and 1K are provided at the centers of the process cartridges 10C and 10K, respectively, and a charging device 2, a developing device 4, and a cleaning device 6 are provided around them.

  The exposure device 3 converts data read by the document reading unit 400 or an image signal sent from the outside such as a PC (not shown), scans the laser beam with a polygon motor, and sensitizes based on the image signal read through the mirror. An electrostatic latent image is formed on the body 1.

  The transfer device 5 is configured to include an endless belt-shaped intermediate transfer belt 50 that sequentially superimposes and holds toner images formed on the respective photoreceptors 1, and color toner formed on the intermediate transfer belt 50. An image is transferred onto a recording sheet. In the intermediate transfer belt 50, a base layer is made of a material that is difficult to stretch, such as a fluororesin or a canvas, and an elastic layer is provided thereon. The elastic layer is made of, for example, fluororubber or acrylonitrile-butadiene copolymer rubber. The surface of the elastic layer is, for example, coated with a fluorine-based resin and covered with a smooth coat layer. Then, it is wound around the support roller 54 so as to be able to rotate and convey clockwise. Further, an intermediate transfer belt cleaning device 53 for removing residual toner remaining on the intermediate transfer belt 50 after image transfer is provided.

  In addition, the recording paper may be conveyed by a transfer conveyance belt, and the toner image formed on each photoconductor 1 may be directly transferred to the recording paper.

  A primary transfer unit 51 is provided at a position facing the photoreceptor 1 with the intermediate transfer belt 50 interposed therebetween. The primary transfer means 51 is connected to a power source (not shown), and a voltage is applied when transferring the toner image on the photoreceptor 1 to the intermediate transfer belt 50, so that an electric field is generated between the photoreceptor 1 and the intermediate transfer belt 50. The toner image is transferred electrostatically. On the other hand, a secondary transfer device 52 is provided with the intermediate transfer belt 50 interposed therebetween. In the illustrated example, the secondary transfer device 52 includes a secondary transfer belt, which is an endless belt, between two rollers, and transfers an image on the intermediate transfer belt 50 to a sheet.

  Next to the secondary transfer device 52, a fixing device 7 for fixing the transferred image on the sheet is provided. The fixing device 7 is composed of a belt stretched around a roller having a halogen heater or the like inside and a pressure roller, and applies heat and pressure to the toner on the recording paper at a nip portion formed by both the toner. Fix the image. In addition, a pair of rollers or a pair of belts may be used.

In addition, the copying machine 100 includes a double-sided reversing unit 9, a paper discharge tray 8, and the like.
FIG. 3 is an enlarged view of the process cartridge 10 of FIG. The photoconductor 1 can be made of amorphous metal having photoconductivity, amorphous metal such as amorphous selenium, or organic compound such as bisazo pigment or phthalocyanine pigment. In consideration of environmental problems and post-treatment after use, a photoreceptor using an organic compound is preferable.

  The charging device 2 is the scorotron charging device 2 and includes a charge wire 21, a shield case 22, a grid electrode 23, and a power source (not shown) connected to the charge wire 21 and the grid electrode 23. A high voltage is applied to each of the charge wire 21 and the grid electrode 23 to generate a corona discharge between the photoconductor 1 and the charge wire 21 to uniformly charge the surface of the photoconductor 1. The grid electrode 23 is arranged in a shape along the curvature of the photoreceptor 1 in order to improve the potential controllability. In addition, a charge cleaning device 24 is disposed in order to maintain stable charging performance over time.

  The exhaust duct 11 is connected to the exhaust duct on the back of the copying machine 100, and the gas in the apparatus containing ozone generated during discharge is discharged from the exhaust duct 11 to the outside of the apparatus through the ozone treatment filter.

  The developing device 4 includes a developing roller 41 that is a developer carrying member that carries the developer and supplies the developer 1 to the photoreceptor 1, a toner supply screw 42, and the like. The developing roller 41 includes a hollow cylindrical developer carrying member that is rotatably supported, and a magnet roll fixed coaxially with the inside of the developer carrying member, and the outer periphery of the developer carrying member. A developer is magnetically attracted to the surface and conveyed. The developer carrying member is made of a non-magnetic member that is electrically conductive, and is connected to a power source (not shown) for applying a developing bias. A voltage is applied from the power source between the developing roller 41 and the photosensitive member 1 to form an electric field in the developing region.

  The cleaning device 6 includes a cleaning blade 61, a cleaning brush roller 62, and a waste toner discharge screw 63, and removes transfer residual toner remaining on the photosensitive member 1 after the primary transfer to prepare for image formation again.

  The charging device 2, the developing device 4, the cleaning device 6, and the photosensitive member 1 are integrally formed process cartridges that can be attached to and detached from the copying machine 100, and can be replaced integrally with the copying machine 100.

Next, the scorotron charging device 2 will be described.
As shown in FIGS. 4 and 5, end blocks 25 made of insulating resin are fixed to both ends in the longitudinal direction of the shield case 22, and the charge wires 21 and the grid electrodes 23 are fixed to the end blocks 25. . The grid electrode 23 is pulled from the grid electrode hooking portion 251 of the end block 25 and is stretched into a curvature shape by following the curvature forming portion 252 of the end block 25. In this embodiment, the grid electrode 23 is disposed at a distance of 2 [mm] from the surface of the photoreceptor 1, and the charge wire 21 is disposed at a distance of 6 [mm] from the surface of the photoreceptor 1.

  As described above in the present embodiment, the grid electrode is stretched in the above-described curvature shape so that the distance between the photoconductor 1 and the grid electrode 23 does not vary depending on the location as shown in FIG. This is because the distance between the photoconductor 1 and the grid electrode 23 is made constant regardless of the location by causing the grid electrode 23 to follow the curvature of the photoconductor 1 as shown in FIG. 6B.

  Further, in the present embodiment, since the counter electrode 221 is provided between the two charge wires 21, the scorotron charging device 2 has a shape with good potential controllability.

  As shown in FIGS. 4 and 7, the electrostatic cleaning device 24 includes a feed screw 241, a slider 242, a grid cleaning member 243, a drive gear 244, a cleaning member holding member 245, and a cover member 246. The slider 242 can be reciprocated in the longitudinal direction of the shield case 22 by rotating the feed screw 241 from the drive gear 244 at (1 stop). When the slider 24 moves in the longitudinal direction, the grid cleaning member 243 held by the cleaning member holding member 245 attached to the slider 242 moves in the same direction while being in contact with the grid electrode 23, so that the grid electrode 23 is moved. It is configured to be cleaned.

  In the scorotron charging device 2 of the present embodiment, the longitudinal end portion (front side in FIG. 4) of the grid electrode 23 outside the effective image forming area of the photoconductor 1 during image formation (during rotation of the photoconductor 1) by the charge cleaning device 24. It can be accommodated in a standby space 247 provided on the side). Further, the grid electrode 23 in the standby space 247 is covered with a cover member 246.

  As shown in FIG. 8, the grid cleaning member 243 is a foamed polyurethane material having a natural length of 5 [mm]. The cover member 246 is a pet sheet material having a thickness of 0.2 [mm], and is previously processed by hot pressing into a shape along the curvature of the photosensitive drum 1. By making the cover member 246 into a pet sheet material, the thickness C of the grid cleaning member 243 on the cover member 246 in the standby space 247 can be increased as much as possible during non-cleaning. Further, by forming the cover member 246 in an arc shape, the secondary moment of section can be increased compared to the flat plate shape, and the cover member 246 can be further thinned. Furthermore, since the cover member 246 has been processed into an arc shape in advance, it is not necessary to provide a cover holding member or the like to deform the cover member 246 into an arc shape by the cover holding member, and reliably maintain a highly accurate arc shape. it can.

The cover member 246 is provided with a distance of 0.5 [mm] from the grid electrode 23. The thickness of the cleaning member holding member 245 was 1.2 [mm], and the distance between the cleaning member holding member 245 and the counter electrode 221 was 1 [mm].

  When the electrostatic cleaning device 24 moves to the standby space 247 during non-cleaning in which the grid electrode 23 is not cleaned, the grid cleaning member 24 in contact with the grid electrode 23 as shown in FIG. 1A is shown in FIG. As shown in FIG. 1, the grid cleaning member 243 moves from the grid electrode 23 to the cover member 246 as shown in FIG. 1C by riding on the cover member 246 while being elastically deformed by the movement of the slider 242. Move up. Further, when the electrostatic cleaning device 24 is accommodated in the standby space 247, the grid cleaning member 243 causes the grid electrode 23 to be placed between the grid cleaning member 243 and the grid electrode 23 in the standby space 24. It is not pushed.

  As described above, the grid cleaning member 243 can move on the cover member 246 from the grid electrode 23 by the movement of the slider 242, so that the grid cleaning member 243 can be removed from the grid electrode 23 without using a complicated separation mechanism at the time of non-cleaning. Can be separated. In particular, when the counter electrode 221 is provided between the two charge wires 21 as in the scorotron charging device 2 of the present embodiment, the grid cleaning member 243 is separated from the grid electrode 23 using a complicated separation mechanism including a cam or the like. Since it is difficult to make the structure separated, it is more effective.

  Further, when the electrostatic cleaning device 24 moves out of the standby space 247 during the cleaning for cleaning the grid electrode 23, the procedure is the reverse of that when the electrostatic cleaning device 24 moves into the standby space 247 during non-cleaning, that is, the slider. The grid cleaning member 243 moves as shown in the order of FIG. 1C, FIG. 1B, and FIG. 1A by the 242 so that the grid cleaning member 243 is moved from above the cover member 246 to the grid electrode 23. Can move up.

  As described above, when the natural length A of the thickness of the grid cleaning member 243 is 5 [mm], the thickness of the grid cleaning member 243 at the time of cleaning in which the grid cleaning member 243 at the time of cleaning and the grid electrode 23 are in contact with each other. B is 3 [mm], and the thickness C of the grid cleaning member 243 at the time of non-cleaning (standby) when the grid cleaning member 243 moves to the standby space and the grid cleaning member 243 and the cover member 246 are in contact with each other is 2.3 [ mm].

  Here, as described above, the thickness C of the grid cleaning member during non-cleaning is smaller than the thickness B of the grid cleaning member 243 during cleaning. As can be seen from FIGS. 1B and 1C, the grid cleaning member 243 is compressed in the thickness direction by moving the grid cleaning member 243 from the grid electrode 23 onto the cover member 246. Because. If the amount of deformation of the grid cleaning member 243 on the cover member 246 becomes too large, it will lose its elasticity and partly plastically deform. If plastic deformation occurs in the grid cleaning member 243 in this way, the grid cleaning member 243 is not properly brought into contact with the grid electrode 23 during cleaning, and a sufficient pressing force cannot be obtained, resulting in poor cleaning of the grid electrode 23. It will occur. In order to reduce the compression in the thickness direction of the grid cleaning member 243, it is conceivable to increase the space in the grid cleaning member thickness direction of the standby space 247, but in order to increase the standby space 247, the photosensitive member 1 and It is necessary to increase the distance from the charge wire 21. In this case, the scorotron charging device 2 is increased in size.

Next, an experiment performed using the copying machine 100 of this embodiment will be described.
The natural length A of the thickness of the grid cleaning member 243 is 3 [mm], 4 [mm], 5 [mm], and the thickness B of the grid cleaning member 243 at the time of cleaning is 3 [mm]. When the thickness C of the grid cleaning member 243 is set to 1.3 [mm], 1.8 [mm], and 2.3 [mm], the initial time and the elapsed time (process linear speed 300 [mm / s], A4Y equivalent 100,000) The grid cleaning performance and the 1 × 1 dot image unevenness were confirmed. In addition, the thickness C of the grid cleaning member at the time of non-cleaning was changed by changing the thickness of the cover member 246.

  Evaluation of initial cleaning performance and time-dependent charging performance is “○” when good cleaning performance is recognized, “△” when acceptable cleaning failure is acceptable in actual use, and unacceptable cleaning failure is recognized. Was performed with “×”.

  Evaluation of charging unevenness is performed in 5 stages of 1 × 1 dot image unevenness level. In general, level 3 or lower that causes unacceptable charging unevenness in actual use is impossible (×), and unacceptable charging unevenness does not occur in actual use. Throughout level 4 or higher where charging unevenness does not occur, the test was performed with good (◯).

  Then, a comprehensive judgment was made based on the evaluation of the initial cleaning performance, the evaluation of the charging performance with time, and the evaluation of the unevenness of charging.

Table 1 shows the experimental results.

  As shown in Table 1, it is understood that the initial cleaning performance is good when the cleaning member compression ratio (AB) / A during cleaning is 0.4 or more. This is considered to be because the grid electrode 23 can be cleaned while the grid cleaning member 243 is sufficiently pressed against the grid electrode 23.

  It can also be seen that if the cleaning member compression ratio (AC) / A during non-cleaning is 0.64 or less, the cleaning performance with time is good and the unevenness level of the 1 × 1 dot image is also good. When the cleaning member compression ratio at the time of non-cleaning becomes larger than 0.64, the amount of deformation of the grid cleaning member 243 with time increases (partially plastically deformed), loses elasticity, and the grid electrode 23 at the time of cleaning. It is thought that poor pressing occurred due to insufficient pressing force. This cleaning failure is considered to be a potential deviation of the photoreceptor 1 and appear as density unevenness in the 1 × 1 dot image.

  Thus, by setting the cleaning member compression ratio during cleaning to 0.4 or more and the cleaning member compression ratio during non-cleaning to 0.64 or less, the grid cleaning performance is improved both in the initial stage and over time. It was found that the life of the charging device 2 can be extended. In particular, since the amount of deformation of the grid electrode 243 over time can be reliably suppressed by setting the cleaning member compression ratio during non-cleaning to 0.6 or less, the grid cleaning performance over time can be further increased. And the life of the scorotron charging device 2 can be extended.

  Further, in the scorotron charging device 2 of the present embodiment, a complicated mechanism is not required for separating the grid cleaning member 243 from the grid electrode 23 during non-cleaning, and a cover member made of a pet sheet is provided in the standby space 247. Further, since only the foamed polyurethane grid cleaning member 243 is used, the cost can be reduced.

As described above, according to the present embodiment, the shield case 22 having the discharge opening, the charge wire 21 as the discharge electrode disposed in the shield case 22, and the grid electrode 23 stretched over the discharge opening. And the scorotron charging device 2 including the grid cleaning member 243 that is a cleaning member that cleans the grid electrode 23 by moving in the longitudinal direction of the grid electrode 23 and rubbing against the grid electrode 23. Provided in the area of the grid electrode 23 that faces the outside of the effective image forming area of the photoconductor 1, which is in a predetermined area of the grid electrode 23, which makes the grid cleaning member 243 stand by when the electrode 23 is not cleaned. In the standby space 247 that is a standby location, a cover that covers the surface of the grid electrode 23 that faces the grid cleaning member 243 is provided. The member 246 is provided, and the distance from the surface on the opposite side of the grid electrode 23 to the surface on the opposite side of the surface of the cover member 246 opposite to the grid electrode 23 is the longitudinal length of the grid cleaning member 243 This is the distance that the grid cleaning member 243 can ride on the cover member 246 from the grid electrode 23 outside the standby space 247 by moving in the direction. Thereby, the grid cleaning member 243 can run on the cover member 246 provided in the standby space 247 from the grid electrode 23 outside the standby space 247 by the movement in the longitudinal direction. Therefore, the grid cleaning member 243 can be separated from the grid electrode 23 by moving the grid cleaning member 243 into the standby space 247 when the grid electrode 23 is not cleaned by the grid cleaning member 243. Therefore, the grid cleaning member 243 can be separated from the grid electrode 23 at the time of non-cleaning without providing a complicated separation mechanism, and the cost and size of the apparatus can be reduced.
In addition, since the grid cleaning member 243 is an elastic body, the grid cleaning member 243 rides on the cover member 246 from the grid electrode 23 while being elastically deformed. Therefore, the grid cleaning member 243 is easily moved onto the cover member 246. Can be made. Moreover, the contact force to the grid electrode 23 at the time of cleaning at the initial stage and over time can be reliably maintained, and the cleaning performance is improved.
In addition, by using foamed polyurethane as the grid cleaning member 243, it is possible to increase ozone resistance, increase elasticity, reduce the compressive residual strain rate, and the grid over time due to being pushed from the cover member 246 during non-cleaning. The plastic deformation of the cleaning member 243 can be reliably prevented.
Further, the grid cleaning member 243 is held by the cleaning member holding member 245 movable in the longitudinal direction, and the natural length of the thickness of the grid cleaning member 243 is A, and the grid cleaning member 243 when it is on the grid electrode 23 When the thickness is B and the thickness of the grid cleaning member when it is on the cover member 246 is C, the compression ratio (AB) / A of the grid cleaning member 243 when it is on the grid electrode 23 is 0.4 or more. And the compression ratio (AC) / A of the grid cleaning member 243 when it is on the cover member 246 is configured to be 0.64 or less. As a result, as can be seen from the experimental results described above, the grid cleaning member 243 is pushed from the cover member 246 during non-cleaning (standby) while maintaining a sufficient contact force even during cleaning. Deformation is suppressed, and sufficient contact force can be maintained even during cleaning over time. Therefore, the grid electrode 23 can be reliably cleaned at the initial stage and over time.
Moreover, according to this embodiment, the cover member 246 is made of a pet sheet material that is a sheet-like member, so that the thickness C of the grid cleaning member 243 on the cover member 246 in the standby space 247 is made as large as possible when not cleaning. The compression ratio of the grid cleaning member 243 when it is on the cover member 246 can be reduced.
In addition, according to the present embodiment, the grid electrode 23 and the cover member 246 are arc-shaped, so that the grid electrode 23 can be arranged at a constant interval along the curvature of the photoreceptor 1, and the potential controllability can be improved. It is possible to improve and reduce charging unevenness. Further, by making the cover member 246 arc-shaped, the secondary moment of section can be increased compared to the flat plate shape, and the cover member 246 can be further thinned. Accordingly, the grid cleaning member 243 is prevented from being deformed with time due to being pushed from the cover member 246 during non-cleaning (standby), and the grid cleaning member located on the cover member 246 in the standby space 247 during non-cleaning. The thickness C of 243 can be increased, and the compression ratio of the grid cleaning member 243 when on the cover member 246 can be reduced. Therefore, the grid electrode 23 can be reliably cleaned at the initial stage and over time.
Further, according to the present embodiment, the cover member 246 is processed in an arc shape in advance, so that it is not necessary to provide a cover holding member or the like and deform it into an arc shape by the cover holding member, and a highly accurate arc The shape can be reliably maintained .
Also, according to this embodiment, the photosensitive member 1 as an image bearing member, the charging means and the copier 100 is an image forming apparatus having a to allowed to charge the surface of the photosensitive member 1, of the present invention as a charging unit By using the scorotron charging device 2, it is possible to provide the copying machine 100 that can be reduced in cost, have a long life, and can be downsized.
Further, according to this embodiment, the charging unit and at least one of the photosensitive member 1 as an image carrier, the developing device 4 as a developing unit, and the cleaning device 6 as a cleaning unit are integrally configured. By using the scorotron charging device 2 of the present invention as the charging means in the process cartridge 10 that is detachable from the forming apparatus, it is possible to provide the pros cartridge 10 that can be reduced in cost, can have a long life, and can be downsized. Furthermore, maintenance by the user is facilitated, and serviceability is greatly improved.
Further, according to the present embodiment, the charging unit and at least one of the photosensitive member 1 as an image carrier, the developing device 4 as a developing unit, and the cleaning device 6 as a cleaning unit are integrally configured. By using the process cartridge 10 including the scorotron charging device 2 of the present invention as the process cartridge in the copying machine 100 that is an image forming apparatus including a process cartridge that is detachably attached to the main body, low cost, high life, and miniaturization are achieved. A possible copying machine 100 can be provided. Furthermore, maintenance by the user is facilitated, and serviceability is greatly improved.

The schematic diagram which showed the state which moves a grid cleaning member on a cover member from the grid electrode which is the characterizing part of this invention. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment. The expansion schematic block diagram of a process cartridge. The perspective view of a scorotron charging device. The perspective view which turned over the scorotron charging device. The schematic diagram which shows the relationship between the shape of a grid electrode, and the space | interval between a photoreceptor. The schematic block diagram of a scorotron charging device and a charging cleaning device. The schematic diagram which showed the dimension of the grid cleaning member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging apparatus 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 8 Paper discharge tray 9 Both-side inversion unit 10 Process cartridge 21 Charge wire 22 Shield case 23 Grid electrode 24 Charge cleaning apparatus 25 End block 41 Development Agent carrier 42 Toner supply screw 50 Intermediate transfer belt 51 Primary transfer means 52 Secondary transfer device 53 Intermediate transfer belt cleaning device 54 Support roller 61 Cleaning blade 62 Cleaning brush roller 63 Waste toner discharge screw 100 Image forming apparatus 200 Paper feed unit 221 Counter electrode 241 Feed screw 242 Slider 243 Grid cleaning member 244 Drive gear 245 Cleaning member holding member 246 Cover member 247 Standby space 300 Image forming unit 400 Document reading unit 500 Draft transport unit

Claims (7)

A shield case having a discharge opening;
A discharge electrode disposed in the shield case;
A grid electrode stretched in the discharge opening;
In a scorotron charging device comprising a cleaning member that moves in the longitudinal direction of the grid electrode and cleans the grid electrode by rubbing against the grid electrode,
When the cleaning member does not clean the grid electrode, the cleaning member is made to stand by at a standby position provided in a predetermined region of the grid electrode on the side facing the cleaning member. A cover member that covers the surface is provided,
The distance from the surface on the opposite side of the grid electrode to the surface of the cover member opposite to the surface on the opposite side of the grid electrode is determined by the movement of the cleaning member in the longitudinal direction. It is a distance that can be ridden on the cover member from the grid electrode outside the standby position,
The cleaning member is foamed polyurethane , and the cleaning member is held by a cleaning member holding member movable in the longitudinal direction;
When the natural length of the thickness of the cleaning member is A, the thickness of the cleaning member when it is on the grid electrode is B, and the thickness of the cleaning member when it is on the cover member is C, The compression ratio (A-B) / A of the cleaning member when it is in the range of 0.4 or more, and the compression ratio (A-C) / A of the cleaning member when it is on the cover member is 0.64 A scorotron charging device characterized by the following. The scorotron charging device of claim 1,
The scorotron charging device, wherein the cover member is a sheet. The scorotron charging device according to claim 1 or 2,
The scorotron charging device, wherein the grid electrode and the cover member have an arc shape. The scorotron charging device according to claim 3.
The scorotron charging device according to claim 1, wherein the cover member is previously processed into an arc shape. An image carrier;
In an image forming apparatus provided with charging means for charging the surface of the image carrier,
An image forming apparatus using the scorotron charging device according to claim 1, 2, 3, or 4 as the charging means. In a process cartridge detachably attached to an image forming apparatus, in which a charging unit and at least one of an image carrier, a developing unit, and a cleaning unit are integrally formed.
A process cartridge using the scorotron charging device according to claim 1, 2, 3, or 4 as the charging means. In an image forming apparatus including a process cartridge that is configured integrally with a charging unit and at least one of an image carrier, a developing unit, and a cleaning unit, and is detachable from the apparatus main body.
An image forming apparatus comprising the process cartridge according to claim 6 as the process cartridge.

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