JP4670668B2 - Charging device, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to a charging device that can be used to charge an electrostatic latent image carrier such as a photoreceptor in an electrophotographic image forming apparatus, for example. The present invention also relates to a process cartridge for image formation that includes an electrostatic latent image carrier and a charging device that charges the electrostatic latent image carrier and can be attached to and detached from the image forming apparatus main body. Involved.

  For example, as a typical charging device that can be used to charge an electrostatic latent image carrier such as a photoreceptor in an electrophotographic image forming apparatus, a corona charging type charging device can be given. .

  Corona charging system charging devices are based on whether or not they have a control electrode such as a grid electrode plate having a large number of openings, depending on whether it is a corotron system (a system without a control electrode) or a scorotron system (a control electrode). To be used).

  The scorotron charging device generally includes a shield case having a discharge opening, a discharge electrode disposed in the shield case, and a control electrode facing the discharge electrode and stretched in the discharge opening of the shield case have. The corotron charging device is generally obtained by removing the control electrode from the scorotron charging device.

  In a scorotron charging device, the amount of corona ions flowing into a charged body (for example, a photoreceptor) generated by discharging from a discharge electrode such as a discharge wire can be controlled to be substantially constant by a control electrode set at a constant potential. Therefore, even if the voltage applied to the discharge electrode fluctuates due to some cause, it is possible to suppress the fluctuation of the charging potential to the charged object, and compared with the corotron charging device that does not include the control electrode. There is an advantage that uneven charging can be suppressed. Accordingly, in order to charge an electrostatic latent image carrier such as a photoreceptor in an electrophotographic image forming apparatus, a scorotron charging device is widely used.

  In both the corotron type and scorotron type corona charging devices, discharge products such as ozone and nitrogen oxides are generated with the discharge from the discharge electrode. The discharge electrode is gradually contaminated by such discharge products. In the scorotron charging device, the control electrode is gradually contaminated.

  On the other hand, in an electrophotographic image forming apparatus, dust such as recording medium powder, toner scattered in an electrostatic latent image developing process, a transfer process for transferring a toner image to an intermediate transfer body or a recording medium, etc. are few. Often adhere to the discharge electrode and control electrode (if any) of the charging device mounted on the image forming apparatus, and gradually accumulate in the long-term use of the image forming apparatus. I will do it.

In a scorotron charging device having a control electrode, if a discharge product, dust, scattered toner, or the like adheres to the control electrode facing the discharge electrode and is contaminated, for example, the charging device is connected to the photosensitive member. In the case of a charging device, the control of the amount of corona ions flowing into the photosensitive member by the control electrode becomes unstable, and uneven charging occurs on the surface of the photosensitive member.
For this reason, about the charging device provided with the control electrode, cleaning the control electrode with a cleaning device is performed.

  However, when charging a charged object with a charging device including a control electrode, the distance between the control electrode and the charged object is often set to be very short. For example, when the member to be charged is a photosensitive member, the distance between the photosensitive member and the control electrode is generally set to about 1 mm and is very short. Therefore, it is not easy to arrange a cleaning member for cleaning the control electrode surface directed to the charged body such as the photosensitive body between the charged body and the control electrode.

  In this regard, in JP-A-4-42248, in cleaning the control electrode of the charging device for charging the photosensitive member, the charging device is once moved away from the photosensitive member, and the interval between the control electrode and the photosensitive member is widened. A cleaning device for cleaning the control electrode is described.

  Japanese Patent Application Laid-Open No. 8-62950 discloses a cleaning device that rubs the control electrode while releasing the tension of the control electrode and pressing the cleaning member against the control electrode in a direction away from the photosensitive member. Has been.

  Further, in JP-A-2002-229302, a control electrode is formed of an endless metal wire, and when cleaning the control electrode, the wire portion drawn out of the charging device is cleaned, and the wire portion is charged. A cleaning device is described that feeds the device.

JP-A-4-42248 JP-A-8-62950 JP 2002-229302 A

  However, according to the cleaning device described in Japanese Patent Laid-Open No. 4-42248, the charging device must be moved away from the object to be charged in order to obtain a space for arranging the cleaning member when cleaning the control electrode. A space for moving the charging device away from the member to be charged and a retreat space for the cleaning member during non-cleaning are also required.

  According to the cleaning device described in Japanese Patent Laid-Open No. 8-62950, when cleaning the control electrode, the tension of the control electrode is once relaxed, and the cleaning member is pressed against the control electrode whose tension has been reduced to move away from the charged body. A mechanism is required, and a retreat space for the cleaning member at the time of non-cleaning is also required.

  Therefore, the cleaning apparatus described in Japanese Patent Laid-Open No. 4-42248 and Japanese Patent Laid-Open No. 8-62950 has a large structure for providing the mechanism, and is expensive as much, and the space must be secured. Therefore, the charging device installation space becomes large.

  In the cleaning device described in Japanese Patent Application Laid-Open No. 2002-229302, there is a high possibility that the wire is cut when the wire is cleaned or when the cleaned wire is sent to the charging device. Once the wire is cut, the charging device has a charging function. I can't make it work.

  Therefore, the present invention provides a shield case having an opening for discharge, a discharge electrode disposed in the shield case, a control electrode facing the discharge electrode, provided in the discharge opening of the shield case, and the control electrode A charging device having a cleaning device, which can be formed compactly and inexpensively even if the cleaning device is provided, and the distance is changed even when the distance between the charged object and the control electrode is set short. It is a first object to provide a charging device that can safely clean a control electrode without having to do this.

  The present invention also provides an image forming method in which an electrostatic latent image is formed on an electrostatic latent image bearing member, the electrostatic latent image is developed to form a visible toner image, and the toner image is transferred to a transfer target. Charging device for charging the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image as a process cartridge detachable from the image forming apparatus main body for the apparatus The charging device portion can be made compact and inexpensive, so that the whole can be formed compactly and inexpensively, and the process for image formation required for the process cartridge can be stably performed over a long period of time. A second problem is to provide a process cartridge.

  The present invention further forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer object. A third object is to provide an image forming apparatus that can form a good image over a long period of time.

In order to solve the first problem, the present invention
Shield case having discharge opening, discharge electrode arranged in shield case, control electrode facing discharge electrode and provided in discharge opening of shield case, and charging device having cleaning device for control electrode The cleaning device is wound around the control electrode in a direction transverse to the longitudinal direction of the control electrode, and is moved in the longitudinal direction of the control electrode to rub and clean both surfaces of the control electrode. Provided is a charging device including a cleaning member and a cleaning member driving unit that moves the cleaning member along a longitudinal direction of the control electrode.

  According to the charging device of the present invention, the cleaning device for cleaning the control electrode is wound around the control electrode in a direction crossing the longitudinal direction of the control electrode, and is moved in the longitudinal direction of the control electrode. A wrapping cleaning member that rubs and cleans both surfaces of the cleaning member, and a cleaning member driving unit that is sufficient if the cleaning member can be moved at least along the longitudinal direction of the control electrode. Since the charging device as a whole can be formed, it can be formed compactly and inexpensively even if it has a control electrode cleaning device.

  The cleaning member may be, for example, a strip-shaped cleaning member having a circular cross-section, a strip-shaped strip-shaped cleaning member having a rectangular cross-section, and the thickness in the direction of the distance between the control electrode and the body to be charged is smaller than the distance. Thus, even when the charging device is used with a short distance between the control electrode and the body to be charged, the cleaning member and the body to be charged are disposed. There is little risk of damage to the cleaning member itself and the object to be charged due to the contact, and the cleaning member is disposed and moved at a short distance so that both surfaces of the control electrode can be rubbed and cleaned safely. There is no need to change the distance between the control electrode and the object to be charged.

In the charging device according to the present invention, examples of the discharge electrode include a discharge wire, a sawtooth discharge needle and a discharge pin formed at a predetermined interval, and the like.
Various types of control electrodes can be used, such as a conductive plate with a number of slits formed on it, a combination of conductive wires in a mesh shape, etc., but in any case with a large number of openings The control electrode can be rubbed and cleaned by winding the cleaning member and moving it in the longitudinal direction of the control electrode. When the cleaning member is wound and rubbed, a plate-like member is desirable as a whole.

  Examples of the cleaning member driving unit include one that includes a screw conveyor disposed along a one-side ear extending in the longitudinal direction of the control electrode. In this case, the winding cleaning member is connected to the shaft of the screw conveyor at the connecting portion, and the connecting portion is sent by the spiral portion on the shaft by the rotation of the screw conveyor shaft, so that the winding is wound around the control electrode. The cleaning member thus moved may be moved to rub and clean the control electrode.

  When such a cleaning member drive unit is employed, the connecting portion of the winding cleaning member to the screw conveyor shaft can be sent by the spiral portion on the shaft by the rotation of the screw conveyor shaft, whereby the control electrode As long as the cleaning member wound around can be moved and rubbed and cleaned by the control electrode, as a typical example of a simple one, the same member (winding) as the cleaning member that is integrally continuous with the winding cleaning member It may also be a part of a hanging cleaning member. The following can be mentioned as an example at the time of using such a connection part.

  That is, the cleaning member driving unit includes a screw conveyor disposed along one side ear portion extending in the longitudinal direction of the control electrode, and the winding cleaning member is wound around the control electrode and the shaft of the screw conveyor. The portion wound around the shaft of the cleaning member is sent by the spiral portion on the shaft by rotation of the screw conveyor shaft, so that the portion wound around the control electrode of the cleaning member is In this case, the control electrode is moved and rubbed and cleaned. An example of such a winding cleaning member is a cleaning member that is continuous in an endless ring shape.

The winding cleaning member may be wound in the shape of a figure 8 across the control electrode and the shaft of the screw conveyor so as to cross between the one-side ear portion of the control electrode and the screw conveyor shaft. By being wound in this way, the cleaning member can move more reliably as the screw conveyor shaft rotates.
In any case, the winding cleaning member may be rotated along the control electrode and the shaft following the rotation of the shaft of the screw conveyor. By rotating in this way, the control electrode plate can be rubbed and cleaned more reliably.

For reference, the cleaning member driving unit may be a simpler cleaning member operating member that is connected to a cleaning member wound around the control electrode and can be moved in the longitudinal direction of the control electrode. The inclusion can also be mentioned. In this case, by moving the operation member relative to the control electrode along the longitudinal direction of the control electrode, the cleaning member wound around the control electrode is moved relatively to move the control electrode. Rubbing can be cleaned.
The operating member may be moved manually or may be moved by other means.

  As another example of the means, the operation member is a member capable of abutting against a stationary member outside the charging device, and the control electrode is extended with respect to the operation member in a state where the manipulation member is in contact with the stationary member. By moving the control electrode along the direction (for example, moving the control electrode together with the shield case and the discharge electrode), the cleaning member wound around the control electrode is moved relative to the control electrode to slide the control electrode. The case where it can be rubbed and cleaned can be mentioned.

In this case, the stationary member outside the charging device, a charging device to form an electrostatic latent image on an electrostatic latent image bearing member to form a visible toner image by developing the electrostatic latent image, the toner In the case of a charging device for an image forming apparatus that transfers an image to a transfer target, a stationary member provided in the image forming apparatus, which is pressed when the charging device is mounted on the image forming apparatus As will be described later, the charging device forms an electrostatic latent image on the electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and the toner image is transferred. In a case where the charging device is mounted on a process cartridge that is detachable from the image forming apparatus main body for the image forming apparatus to be transferred to the body, it is pressed when the process cartridge is mounted on the image forming apparatus main body. To the image forming apparatus main body. The stationary member being kicked be exemplified.

  In addition, when the charging device is detachable from the main body of the process cartridge, a stationary member in the process cartridge main body that is pressed when the charging device is attached to the process cartridge main body can be exemplified.

  In any case, a magnet that can be attracted to the stationary member may be provided on the cleaning member operation member. By providing the magnet, the charging device can be attached to and detached from the process cartridge body when the charging device is mounted on the image forming apparatus, or when the charging device mounted on the process cartridge is mounted on the image forming apparatus together with the process cartridge. Not only when the charging device is mounted on the process cartridge, but also when the charging device is pulled out from the image forming apparatus, when pulled out from the image forming apparatus main body together with the process cartridge, or when pulled out from the process cartridge, the stationary member is used by the magnet. The control electrode can be moved along the longitudinal direction with respect to the operation member adsorbed on the control member, and thereby the control electrode can be moved with respect to the cleaning member wound around the control electrode to clean the control electrode by rubbing. .

As already mentioned, the cleaning member, for example, the cross-sectional shape is circular strip-like cleaning member, the cross-sectional shape may be exemplified such as rectangular strip-shaped cleaning member. When a strip- shaped cleaning member having a rectangular cross-sectional shape is employed, the cleaning member may be bent and wound around the control electrode so as to sandwich the control electrode from both sides.
Here, the “strip shape” refers to a state in which the length is sufficiently long compared to the cross-sectional area and the strip is continuous as a whole.

  Regardless of whether the cross-sectional shape is circular, rectangular or the like, the material of the cleaning member is a fibrous thread, tungsten-based metal wire, synthetic resin, etc., as long as the cleaning member can rub and clean the control electrode Various materials such as rubber (for example, polyamide resins and vinyl resins typified by nylon) can be employed.

  If the above-mentioned endless ring-shaped cleaning member is adopted, synthetic resin, rubber, etc. that can be formed on the ring-shaped cleaning member by injection molding or the like are convenient, but materials that are difficult to form into an endless ring shape such as a metal wire When adopting, if there is no hindrance, both ends of the strip-like member may be connected by caulking and connecting with a member made of resin, metal or the like.

  Further, the sectional size of the cleaning member, in particular, the thickness or thickness in the direction of the distance from the control electrode to the object to be charged is used for the charging device according to the present invention, for example, carrying an electrostatic latent image such as a photoreceptor. Depending on whether the surface of the body is to be charged, in particular, a distance smaller than the distance may be selected according to the distance for charging set between the body to be charged and the control electrode. For example, if the charging device charges the surface of the electrostatic latent image carrier such as a photoconductor, a generally adopted distance (about 1 mm) between the control electrode and the electrostatic latent image carrier is considered. A thickness or thickness of about 0.5 mm or less is often preferred.

In any case, the cross-sectional shape, thickness or thickness, material, and the like of the cleaning member can be appropriately selected and adopted according to the structure of the charging device, the application, the member to be charged, and the like.
In any case, the cleaning member may be the following. That is, the cleaning member main body wound around the control electrode and a rubbing portion supported by the main body portion, the rubbing portion rubbing the control electrode surface facing the discharge electrode, and the cleaning member The portion of the main body that faces the surface opposite to the surface facing the discharge electrode of the control electrode rubs against the opposite side surface.

  In order to solve the second problem, the present invention forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and covers the toner image. A process cartridge for an image forming apparatus to be transferred to a transfer body, detachable from the main body of the image forming apparatus, wherein the electrostatic latent image carrier and the surface of the electrostatic latent image carrier are covered with the electrostatic latent image. Provided is a process cartridge including a charging device for charging prior to formation, and the charging device according to the present invention as the charging device.

  In the process cartridge according to the present invention, the charging device according to the present invention is a charging device that charges the surface of the electrostatic latent image carrier mounted on the surface of the process cartridge prior to forming the electrostatic latent image. Therefore, the entire process cartridge can be formed compactly and inexpensively, and the image forming process required for the process cartridge can be stably performed over a long period of time.

The process cartridge according to the present invention includes a developing device that develops an electrostatic latent image formed on an electrostatic latent image carrier into a visible toner image, and a toner that remains on the electrostatic latent image carrier after toner image transfer. A cleaning device that removes and the like may be provided.
The process cartridge according to the present invention may be for a monochrome image forming apparatus or a color image forming apparatus.

The present invention also solves the third problem,
An image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target. One or more charging devices including a charging device for charging the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image are provided, and at least one of the charging devices is a charging device according to the present invention. An image forming apparatus is provided.

  According to the image forming apparatus of the present invention, at least one of the charging devices is the charging device according to the present invention, and even when the distance between the object to be charged and the control electrode of the charging device is set short, the distance Since the control electrode can be safely cleaned without changing the image quality, a better image can be formed when viewed as the entire image forming apparatus.

The image forming apparatus according to the present invention may be a monochrome image forming apparatus or a color image forming apparatus.
The image forming apparatus according to the present invention may employ the process cartridge according to the present invention.

The image forming apparatus to which the process cartridge according to the present invention is detachable and the image forming apparatus according to the present invention are described as follows: “An electrostatic latent image is formed on an electrostatic latent image carrier, and the electrostatic latent image is developed to be visible. An image forming apparatus that forms a toner image and transfers the toner image to a transfer medium.
Here, the “transfer object” is a recording medium such as normal recording paper in a monochrome image forming apparatus, and the toner image transferred to the recording medium is fixed to the recording medium.
In the color image forming apparatus, the “transfer object” is generally an intermediate transfer member such as an intermediate transfer belt, and the toner image primarily transferred to the intermediate transfer member is further transferred to the recording medium as a secondary transfer. And fixed.
In a color image forming apparatus, an image in which a toner image formed on an electrostatic latent image carrier such as a photoconductor is transferred to a recording medium electrostatically supported on a charged recording medium support. There is also a forming device. In this case, the “transfer object” is the recording medium.

  As described above, according to the present invention, the shield case having the discharge opening, the discharge electrode disposed in the shield case, the control electrode facing the discharge electrode and provided in the discharge opening of the shield case And a charging device having a cleaning device for the control electrode, which can be formed compactly and inexpensively even if the cleaning device is provided, and even when the distance between the object to be charged and the control electrode is set short. Thus, it is possible to provide a charging device that can safely clean the control electrode without changing the distance.

  Further, according to the present invention, an image in which an electrostatic latent image is formed on an electrostatic latent image carrier, the electrostatic latent image is developed to form a visible toner image, and the toner image is transferred to a transfer target. Charging for forming the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image in a process cartridge that is detachable from the main body of the image forming apparatus. This is a process cartridge equipped with a device, and the charging device part can be made compact and inexpensive, so that the whole can be formed compactly and inexpensively, and the process for image formation required for the process cartridge can be carried out stably over a long period of time. A process cartridge capable of being provided can be provided.

  Further, according to the present invention, an electrostatic latent image is formed on an electrostatic latent image carrier, the latent electrostatic image is developed to form a visible toner image, and the toner image is transferred to a transfer target image. An image forming apparatus capable of forming a good image over a long period of time can be provided.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an example of an image forming apparatus provided with an example of a charging device (charging device 2) according to the present invention. FIG. 2 is a perspective view of the entire charging device 2. FIG. 3 is a plan view of the control electrode 23. 4 is a perspective view of a portion including one end portion of the charging device 2, and FIG. 5 is a perspective view of a portion including the other end portion of the charging device 2. FIG. 6 is a cross-sectional view of the charging device 2. FIG. 7 is a diagram illustrating an operation state of the cleaning device 200.

  The image forming apparatus in FIG. 1 is a printer PR1 that forms a monochrome image (prints a monochrome image). The printer PR1 includes an electrostatic latent image carrier 1 and a charging device 2, an image exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6 and the like sequentially arranged around the electrostatic latent image carrier 1.

Here, the image carrier 1 is a drum-type negatively chargeable photoconductor.
The charging device 2 is a scorotron charging device that charges the surface of the photosensitive member 1 by corona discharge, which will be described in detail later.
In this example, the image exposure apparatus 3 performs exposure using a laser beam, and can perform image exposure on the photoreceptor 1 in accordance with image information provided from a personal computer (not shown).

  The developing device 4 is a developing device that reversely develops the electrostatic latent image on the photoreceptor 1 using negatively chargeable toner. Development of the electrostatic latent image on the photoreceptor 1 is performed by a developing roller 41 that carries toner and transports it to the developing area.

The transfer device 5 includes a transfer roller 51 in this example.
In this example, the cleaning device 6 has a cleaning blade 61 disposed in contact with the surface of the photoreceptor 1.

  The photoreceptor 1, the charging device 2, the developing device 4, and the cleaning device 6 are mounted on a cartridge case 91 and form a process cartridge 9 together with the case. The process cartridge 9 is detachable from the main body of the image forming apparatus.

  The printer PR1 is also provided with a storage cassette (not shown) for the recording medium S such as recording paper, and the recording medium S stored in the cassette is pulled out one by one by a medium supply roller (not shown). The roller pair 7 can be supplied.

  In the recording medium conveyance direction, a fixing device 8, a medium discharge roller pair (not shown), and a medium discharge tray are provided on the downstream side of the transfer device 5.

  The charging device 2 includes a discharge electrode 21 (see also FIGS. 5 and 6) that extends long in the same direction as the rotation axis of the photoreceptor 1, and a shield case 22 that holds and stretches the discharge electrode from three sides. Is included. The shield case 22 has an opening 220 (see FIG. 6) that opens toward the photoreceptor 1 for discharging, and a control electrode 23 is stretched over the opening.

  In this example, the discharge electrode 21 is a series of sawtooth discharge needles. The discharge electrode may be made of a discharge wire or the like.

As shown in FIG. 3, the control electrode 23 is a rectangular plate that extends in the same direction as the discharge electrode 21 as a whole, and a plurality of slit openings 231 are formed in the short and long directions of the electrode 23. Are formed at substantially equal intervals.
Note that only a part of the opening 231 is shown in FIG. 2, and the other openings are not shown. 4 and 5 and the like, the opening 231 is not shown, and a region where the opening 231 is provided is indicated as 230.

As shown in FIG. 3 and the like, a hooking hole 232 h is formed at one end 232 outside the region 230 where the opening 231 is formed, and a hooking hole 233 h is also formed at the other end 233.
The control electrode 23 is in a state in which each of the one end portion 232 and the other end portion 233 is in contact with a pair of height positioning portions 221 and 222 (see FIGS. 4 and 5) provided in the shield case 22. The hole 232h of the one end 232 is hooked on a hook 241 (see FIG. 4) at a fixed position located outside the positioning portion 221, and the hook 242 (see FIG. 4) where the hole 233h of the other end 233 is located outside the positioning portion 222. 5) and is stretched.

  In addition to the above, the charging device 2 also has a cleaning device 200 for rubbing and cleaning the control electrode 23. The cleaning device 200 includes an endless ring-shaped winding cleaning member 201 wound around the control electrode in a direction crossing the longitudinal direction of the control electrode 23. Furthermore, the cleaning member drive part D is included. The cleaning member driving unit D includes a screw conveyor 202 that is located outside the control electrode plate 23 and extends along one side ear portion of the control electrode plate 23.

The screw conveyor 202 is obtained by winding and fixing a helical coil 202c around a shaft 202s. The end portion of the shaft 202s is rotatably supported by a bearing device 203 (see FIG. 4) provided at one end of the shield case 22 and a bearing device 204 (see FIG. 5) provided at the other end of the case.

  As shown in FIG. 5, a joint 205 is provided at a portion of the shaft 202s protruding from the bearing device 204. When the process cartridge 9 is mounted on the printer body, the joint 205 serves as a joint of the drive unit in the printer body. Can be engaged. The screw conveyor 202 can be rotated by a predetermined timing of the control electrode cleaning by the driving unit. The rotational drive of the screw conveyor 202 may be performed by a motor mounted on the charging device 2 itself, a motor mounted on the process cartridge 9, or the like.

In this example, the cleaning member 201 is an endless ring-shaped strip-shaped member made of polyamide resin and having a circular cross section (diameter: approximately 0.5 mm), and is wound around the control electrode 23 and the shaft 202s of the screw conveyor 202. It has been. More specifically, the cleaning member 201 is wound in the shape of a figure 8 across the control electrode 23 and the screw conveyor shaft 202s so as to cross between the one-side ear portion of the control electrode 23 and the screw conveyor shaft 202s. A portion 201b wound around the shaft 202s of the cleaning member 201 is located between adjacent coil portions on the shaft (see FIGS. 6 and 7).

  FIG. 6 is a schematic cross-sectional view of the charging device 2 as viewed from the one end side to the other end side. In FIG. 6, the cleaning member 201 is shown separated from the control electrode 23 for easy understanding. However, in actuality, the cleaning member 201 is wound around the control electrode 23 and is in contact with both the surface of the control electrode 23 facing the discharge electrode 21 and the opposite surface. is doing.

  When the screw conveyor 202 is rotated in the β direction in FIGS. 4, 5, and 6, the cleaning member 201 rotates in the shape of a figure 8 along the outer periphery of the control electrode 23 and the screw conveyor shaft 202 s and the cleaning member 201. Of these, the portion 201b wound around the screw conveyor shaft 202s is sent to the spiral coil 202c, so that the portion 201a wound around the control electrode 23 extends in the longitudinal direction of the control electrode plate 23 in the charging device shown in FIG. It moves toward the other end of the charging device shown in FIG. 5 from the home position P on one end (the front end in FIG. 4). When the conveyor 202 is rotated in the reverse direction, the cleaning member 201 moves toward the home position P.

  For example, when the cleaning member 201 moves in a direction away from the home position due to the rotation of the conveyor 202, as shown in FIG. 7, the cleaning member 201 includes a portion 201b wound around the shaft 202s. On the drive side, the part 201a wound around the control electrode 23 becomes the driven side, and the part 201a is slightly delayed from the part 201b and moves in the longitudinal direction of the control electrode with an inclination of α °, and on the peripheral surface of the control electrode 23. The control electrode 23 is rubbed and cleaned by rotating.

  The inclination α ° of the cleaning member 201 that affects the rubbing cleaning of the control electrode 23 and the tension applied to the cleaning member 201 include the material of the cleaning member 201, the circumferential length, the rotational speed of the screw conveyor 202, the helical lead length of the helical coil 202c, Since it varies depending on factors such as sliding resistance between the cleaning member 201 and the control electrode 23, these factors may be appropriately selected and determined so that the control electrode 3 can be cleaned smoothly.

  According to the printer PR1 described above, the process cartridge 9 is mounted on the printer PR1 main body as a precondition for image formation. When the process cartridge 9 is mounted on the printer PR1 main body, the distance between the control electrode 23 of the charging device 2 and the photosensitive member 1 is about 1 mm in this example.

  In a state where the process cartridge 9 is mounted on the printer body, the photosensitive member 1 is rotated in the clockwise direction CW in the drawing by a photosensitive member driving motor (not shown), and the surface thereof is applied with a voltage from a power source (not shown). 2 is charged to a predetermined potential, and image exposure according to the image to be formed is performed from the image exposure device 3 to the charged area, thereby forming an electrostatic latent image. This electrostatic latent image is developed by the developing roller 41 of the developing device 4 to be a visible toner image. At this time, a developing bias voltage is applied to the developing roller 41 from a power supply (not shown) and is driven to rotate by a developing motor (not shown).

  On the other hand, the recording medium S is pulled out from a cassette (not shown) by a medium supply roller and supplied to the timing roller pair 7. The rotation of the timing roller pair 7 is turned on and off by a clutch (not shown), and the recording medium S is supplied to the transfer region as the toner image on the photoreceptor 1 arrives at the transfer roller 51. Then, the toner image on the photosensitive member 1 is transferred to the recording medium S by the transfer roller 51 to which a transfer bias is applied from a transfer power supply (not shown), and then the recording medium S is passed through the fixing device 8 and the toner. The image is fixed under heat and pressure and discharged onto a tray (not shown). In this way, an image is formed.

The toner remaining on the photoreceptor 1 by the toner image transfer is removed and cleaned by the cleaning device 6.
Further, discharge products adhering to and deposited on the control electrode 23 by using the charging device 2 and foreign matters such as dust and scattered toner can be rubbed and cleaned by the cleaning device 200 at a timing that does not hinder image formation.

  The cleaning member 201 of the cleaning device 200 is initially disposed at a home position P (a home position that does not interfere with image formation) facing an area outside the image forming area on the transfer target (the recording medium S in this example). (See FIG. 4).

  When the control electrode 23 is cleaned, the screw conveyor 202 is installed in the drive unit in the printer PR1 in which the shaft joint 205 of the cleaning device 200 is engaged because the process cartridge 9 is mounted on the main body of the printer PR1. 5 and 6, thereby rotating the cleaning member 201 around the control electrode 23 and the screw conveyor shaft 202 s while moving the home position (see FIG. 4) to the other end side of the charging device 2, and the control member 23 can be rubbed and cleaned by the cleaning member 201 accordingly.

  Thus, the cleaning member 201 that has moved to the other end side of the charging device may wait for the next cleaning at a position on the other end side that does not hinder image formation. You may return to your home position. In any case, the control electrode 23 may be rubbed back and forth depending on the degree of contamination, rubbed by forward or backward movement, or rubbed twice or more. May be. The stop position of the cleaning member 201 may be a position that does not hinder image formation. When the cleaning member 201 exits from the initial position and returns to the home position and stops again, the cleaning member 201 may stop at an angle opposite to the same angle as α °. I do not care.

  According to the charging device 2 described above, the cleaning device 200 for cleaning the control electrode 23 can be formed in a compact and inexpensive structure. Therefore, the charging device 2 as a whole has the cleaning device 200 for the control electrode 23. Can be made compact and inexpensive.

  The cleaning member 201 is formed of a strip-shaped cleaning member 201 having a circular shape with a diameter of about 0.5 mm which is smaller than the distance of about 1 mm between the control electrode 23 and the photosensitive member 1 and is wound around the control electrode 23. Therefore, even if the distance between the photoconductor 1 and the control electrode 23 is short, there is little risk of damage to the cleaning member 201 itself and the photoconductor 1 due to the contact between the cleaning member 201 and the photoconductor 1, and the cleaning member 201 is within the short distance. Can be rotated and moved to safely rub and clean both sides of the control electrode 3.

  Further, since the charging device mounted on the process cartridge 9 is the above-described charging device 2, the charging device portion can be made compact and inexpensive, and the whole can be formed compactly and inexpensively, and the control electrode 23 can be safely formed. The process for image formation required for the process cartridge can be performed stably for a long period of time by cleaning.

  The printer PR1 as a whole employs the charging device 2 as a charging device for charging the photosensitive member 1, so that a good image can be formed over a long period of time.

The cleaning member 201 in the cleaning device 200 for the control electrode 23 of the charging device 2 described above is a strip cleaning member 201 having a circular cross section. However, as the cleaning member, a strip-shaped strip cleaning member having a thin cross section is rectangular. Can also be adopted.
FIG. 8 shows an example. A cleaning device 200A shown in FIG. 8 includes a cleaning member 201 ′ and a cleaning member driving unit DA that drives the cleaning member in the longitudinal direction of the control electrode. The drive part DA has substantially the same structure as the drive part D in the cleaning device 200, and is mainly composed of the screw conveyor 202.

The cleaning member 201 ′ is a cleaning member formed by bending a belt-shaped resin molded product having a thickness smaller than the gap distance between the control electrode 23 and the photosensitive member 1. It is bent at locations a1 and a2, and is wound around the control electrode in such a manner as to sandwich the control electrode 23 from both sides. One end at of the cleaning member 201 ′ is bent between the control electrode 23 and the conveyor 202, and is engaged with a portion of the cleaning member 201 ′ on the photoconductor 1 side, and the other end at ′ is the conveyor shaft 202s. As a connecting part to the shaft, it is wound around and connected to the shaft.

  In FIG. 8, the cleaning member 201 ′ is shown separated from the control electrode 23 for easy understanding. However, in reality, the cleaning member 201 ′ is in contact with the control electrode 23, so that the electrode is sandwiched between both surfaces of the control electrode 23 facing the discharge electrode 21 and the opposite surface. is doing.

  According to the cleaning device 200A of FIG. 8, the screw conveyor 202 is rotated and the cleaning member connecting portion at ′ is sent to move the cleaning member 201 ′ in the longitudinal direction of the control electrode, so that both surfaces of the control electrode 23 are rubbed and cleaned. it can.

  In the case of the type of cleaning device shown in FIG. 8, in order to more reliably rub and clean the surface of the control electrode 23 facing the discharge electrode 21, which is more contaminated by the discharge product, as shown in FIG. A rubbing member 206 (for example, a rubbing member made of a flocking cloth, a pile fabric, etc.) is provided on the cleaning member portion located on the surface side by an adhesive means such as a double-sided adhesive tape, and the control electrode surface is You may make it carry out sliding cleaning.

For reference, it is also possible to employ a cleaning device 200B shown in FIG. This apparatus 200B employs a drive unit DB as a simpler cleaning member drive unit. The drive unit DB is composed of a cleaning member operation member 207 that can be moved in the longitudinal direction of the control electrode 23. The endless ring-shaped cleaning member 201 is wound around a member 207 a protruding from the control electrode 23 and the operation member 207 in a shape of a letter 8 and connected to the operation member. The operation member 207 has a magnet 208 on the surface opposite to the surface on which the connecting member 207a is projected.

  According to the cleaning device 200B, the operation member 207 and the cleaning member 201 connected to the operation member 207 are positioned in a position where there is no hindrance to image formation at the other end (back side) of the charging device as shown in FIG. When the process cartridge 9 is mounted on the printer PR1 main body, the operation member 207 comes into contact with the stationary member 209 made of a magnetic material in the printer, and the magnet 208 is attracted to the member 209, whereby the operation member 207 is attached to the stationary member. Held in position.

  In this state, when the process cartridge 9 is further pushed into the printer main body or pulled out from the pushed-in state, the control electrode plate 23 is relatively moved with respect to the operation member 207 and therefore the cleaning member 201 connected to the operation member 207. Moves, thereby cleaning the control electrode 23.

  The control electrode 23 can also be cleaned by taking the process cartridge 9 out of the printer body and manually moving the operation member 207.

Although the printer described above forms a monochrome image, the present invention can also be applied to a color image forming apparatus, for example, a tandem type color image forming apparatus.
FIG. 11 shows an example of a tandem type color printer.
A color printer PR2 shown in FIG. 11 has an endless intermediate transfer belt 40 wound around a driving roller 31 and a roller 32 facing the driving roller 31. The transfer belt 40 can be rotated counterclockwise in the figure (arrow direction in the figure) by a driving roller 31 driven by a belt driving unit (not shown).

  A cleaner 9 for cleaning the secondary transfer residual toner and the like on the transfer belt 40 faces the transfer belt portion on the facing roller 32. A secondary transfer roller 50 faces the transfer belt portion on the driving roller 31.

  A surface layer portion of the secondary transfer roller 50 is formed of an elastic material, and is pressed against the intermediate transfer belt 40 by a pressing unit (not shown) to form a nip portion between the intermediate transfer belt 40 and the intermediate transfer belt 40. , Or following the movement of the recording medium S fed into the nip as will be described later. A secondary transfer bias can be applied to the secondary transfer roller 50 from a secondary transfer bias power supply device (not shown).

  Below the secondary transfer roller 50, a timing roller pair 70 is arranged, and further below that, a recording medium accommodation cassette (not shown) containing a recording medium such as recording paper is arranged. A fixing device 80 is provided above the secondary transfer roller 50.

The fixing device 80 includes a fixing roller having a built-in heat source such as a halogen lamp heater (not shown) and a pressure roller pressed against the fixing roller.
The recording medium S stored in a recording medium storage cassette (not shown) can be pulled out one by one by a medium supply roller (not shown) and supplied to the timing roller pair 70.

  Between the rollers 31 and 32 around which the intermediate transfer belt 40 is wound, the yellow image forming unit Y, the magenta image forming unit M, the cyan image forming unit C, and the rollers 32 to 31 are arranged along the transfer belt 40. Black image forming portions K are arranged in this order.

  Each of the image forming units Y, M, C, and K includes a drum-type photoconductor 11 as an electrostatic latent image carrier, and a charging device 12, an image exposure device 13, and a developing device 14 are provided around the photoconductor. A primary transfer roller 15, a cleaning device 16 for removing and cleaning the primary transfer residual toner on the photosensitive member, and the like are arranged in this order.

The photoreceptor 11, the charging device 12, the developing device 14, and the cleaning device 16 in each image forming unit are provided in a cartridge case, and form a process cartridge together with the cartridge case. That is, the yellow process cartridge YC for forming the yellow image forming portion Y, the magenta process cartridge MC for forming the magenta image forming portion M, the cyan process cartridge CC for forming the cyan image forming portion C, and the black image forming This is a black process cartridge KC for forming the portion K.
Each process cartridge is detachable from the printer body.

  Although not shown in detail in FIG. 6, the charging device 12 in each image forming unit is a charging device having the same configuration as the charging device 2 of the printer PR1 in FIG.

The primary transfer roller 15 faces the photoconductor 11 with the transfer belt 40 therebetween, and rotates as the belt travels. A primary transfer bias for primary transfer of a toner image formed on the photoreceptor 11 to the belt 40 can be applied to the primary transfer roller 15 from a primary transfer bias power supply device (not shown).
The exposure device 13 can perform image exposure on the photoconductor 11 using a laser beam in accordance with image information provided from a personal computer (not shown).

The photoconductor 11 in each image forming unit is a negatively chargeable photoconductor here, and can be driven to rotate clockwise in the drawing by a photoconductor drive motor (not shown).
A charging voltage can be applied to the charging device 12 in each image forming unit at a predetermined timing from a charging power supply device (not shown).

  The developing device 14 in each image forming unit employs a negatively chargeable toner in this example, and an electrostatic latent image formed on the photoconductor 11 is transferred from a developing bias applying power supply device (not shown) to a developing bias voltage. Can be reversely developed by the developing roller 141 to which is applied.

According to the printer PR2, an image can be formed using one or more of the Y, M, C, and K image forming units.
Taking a case where a full color image is formed using all of the image forming portions Y, M, C, and K as an example, first, a yellow toner image is formed in the yellow image forming portion Y, and this is formed on the transfer belt 40 as a primary. Transcript.

  That is, in the yellow image forming unit Y, the photosensitive member 11 is rotationally driven in the clockwise direction in the drawing, and the image exposure device is applied to the charged area of the photosensitive member 11 whose surface is uniformly charged to a predetermined potential by the charging device 12. 13, yellow image exposure is performed, and a yellow electrostatic latent image is formed on the photoreceptor 11. The electrostatic latent image is developed by a developing roller 141 to which a developing bias of a developing device 14 having yellow toner is applied to become a visible yellow toner image, and the toner image is transferred onto the transfer belt 40 by a primary transfer roller 15. Primary transfer is performed. At this time, a primary transfer bias voltage is applied to the primary transfer roller 15 from a power supply device (not shown).

  Similarly, a magenta toner image is formed in the magenta image forming unit M and transferred to the transfer belt 40, a cyan toner image is formed in the cyan image forming unit C and transferred to the transfer belt 40, and in the black image forming unit K. A black toner image is formed and transferred to the transfer belt 40.

Yellow, magenta, cyan, and black toner images are formed at the timing when these toner images are transferred onto the intermediate transfer belt 40 in an overlapping manner.
Thus, the multiple toner images formed on the transfer belt 40 are moved toward the secondary transfer roller 50 by the rotation of the transfer belt 40.

  On the other hand, the recording medium S is pulled out from a recording medium storage cassette (not shown) by the medium supply roller, supplied to the timing roller pair 70, and is on standby.

  Thus, the recording medium S waiting at the timing roller pair 70 is supplied to the nip portion between the transfer belt 40 and the secondary transfer roller 50 in accordance with the multiple toner image sent by the intermediate transfer belt 40. The multiple toner image is secondarily transferred onto the recording medium S by a secondary transfer roller 50 to which a secondary transfer bias is applied from a power supply device (not shown).

  Thereafter, the recording medium S is passed through the fixing device 80, where the multiple toner images are fixed on the recording medium S under heat and pressure. The recording medium S is continuously discharged to a discharge tray by a pair of discharge rollers (not shown).

  The present invention provides a scorotron charging device having a control electrode, a charging device including a cleaning device for the control electrode, a process cartridge including the charging device, and an image forming apparatus including the charging device. Available to:

1 is a diagram illustrating a schematic configuration of an example of an image forming apparatus including an example of a charging device according to the present invention. FIG. 2 is an overall perspective view of the charging device shown in FIG. 1. FIG. 3 is a plan view of a control electrode of the charging device shown in FIG. 2. FIG. 3 is a perspective view of a portion including one end portion of the charging device of FIG. 2. FIG. 3 is a perspective view of a portion including the other end of the charging device of FIG. FIG. 3 is a schematic sectional view of the charging device of FIG. 2. It is a figure which shows the cleaning apparatus operation | movement in the charging device of FIG. It is a figure which shows the other example of a charging device. It is a figure which shows the further another example of a charging device. It is a figure which shows the further another example of a charging device. It is a figure which shows the other example of the image forming apparatus which concerns on this invention.

Explanation of symbols

PR1 Printer 1 Photoconductor 2 Charging device 21 Discharge electrode 22 Shield case 220 Opening portion 23 of case 22 Control electrode 231 Control electrode opening 200 Cleaning device 201 Cleaning member 201a Portion 201b of cleaning member wound around control electrode Part D wound around conveyor shaft Cleaning member drive unit 202 Screw conveyor 202s Screw conveyor shaft 202c Spiral coil 203, 204 Bearing device 205 Joint P Home position 200A Cleaning device 201 'Cleaning member at Cleaning member at end portion at' of cleaning member 201a Cleaning The other end DA of the member 201a The cleaning member driving unit 206 The rubbing member 200B Cleaning device DB The cleaning member driving unit 207 The cleaning member operating member 207a The protruding portion 208 The magnet 209 The stationary member 3 The image exposure device 4 The developing device 41 Roller 5 transfer device 51 transfer roller 6 a cleaning device 61 cleaning blade 7 a pair of timing rollers 8 fixing device 9 process cartridge 91 cartridge case S recording medium

PR2 Color printer Y Yellow image forming unit M Magenta image forming unit C Cyan image forming unit K Black image forming unit YC, MC, CC, KC Process cartridge 11 Photoconductor 12 Charging device 13 Image exposing device 14 Developing device 141 Developing roller 15 1 Next transfer roller 16 Cleaning device 31 Driving roller 32 Opposing roller 40 Intermediate transfer belt 50 Secondary transfer roller 70 Timing roller pair 80 Fixing device 9 Cleaner

Claims (7)

Shield case having discharge opening, discharge electrode arranged in shield case, control electrode facing discharge electrode and provided in discharge opening of shield case, and charging device having cleaning device for control electrode The cleaning device is wound around the control electrode in a direction transverse to the longitudinal direction of the control electrode, and is moved in the longitudinal direction of the control electrode to rub and clean both surfaces of the control electrode. A cleaning member, and a cleaning member driving unit that moves the cleaning member along the longitudinal direction of the control electrode ,
The cleaning member driving unit includes a screw conveyor disposed along one side ear extending in the longitudinal direction of the control electrode, and the winding cleaning member is wound around the control electrode and a shaft of the screw conveyor. The portion wound around the shaft of the cleaning member is sent by the spiral portion on the shaft by rotation of the screw conveyor shaft, so that the portion wound around the control electrode of the cleaning member is A charging device that moves and cleans the control electrode by rubbing . 2. The winding cleaning member is wound in the shape of a figure 8 across the control electrode and the shaft of the screw conveyor so as to cross between the one-side ear portion of the control electrode and the screw conveyor shaft. The charging device described . The charging device according to claim 1, wherein the winding cleaning member is rotated along the control electrode and the shaft in accordance with the rotation of the shaft of the screw conveyor . The charging device according to claim 1, wherein the cleaning member is a strip-shaped cleaning member having a circular cross-sectional shape or a strip-shaped cleaning member having a rectangular cross-sectional shape. An image forming apparatus for forming an electrostatic latent image on an electrostatic latent image carrier, developing the electrostatic latent image to form a visible toner image, and transferring the toner image to a transfer target, A process cartridge that is detachable from the main body of the image forming apparatus, and includes a charging device that charges the surface of the electrostatic latent image carrier and the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image. A process cartridge comprising the charging device according to claim 1. An image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target. 5. One or more charging devices including a charging device that charges the surface of the electrostatic latent image carrier prior to the formation of the electrostatic latent image, wherein at least one of the charging devices is defined in claim 1. An image forming apparatus which is the charging apparatus according to any one of the above. An image forming apparatus that forms an electrostatic latent image on an electrostatic latent image carrier, develops the electrostatic latent image to form a visible toner image, and transfers the toner image to a transfer target. An image forming apparatus comprising the process cartridge according to claim 5.