JP2006171257A - Process cartridge and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent remaining toner after transfer from sticking on a charging roller in an image forming apparatus which has an image carrier, the charging roller coming into contact with the image carrier, an exposing device forming an electrostatic latent image by exposing the image carrier charged by the charging roller, and a development device for developing the electrostatic latent image formed on the image carrier, and collects the remaining toner after transfer sticking on the image carrier, after the toner image on the image carrier has been transferred to an intermediate transfer belt in the devleopment device. <P>SOLUTION: Provided is a toner charging device 30 which charges remaining toner particles T1 and T2 on the image carrier 2Y, before the charging roller 9, to the normal polarity, the toner charging device 30 being disposed apart from the surface of the image carrier 2Y. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus configured as a copying machine, a printer, a facsimile, and the like, and a process cartridge used therefor.

  In an image forming apparatus of a type that transfers a toner image on an image carrier to a transfer material by forming a transfer electric field between the image carrier and a transfer material that moves in contact with the image carrier, an image after transfer Transfer residual toner adheres to the surface of the carrier. If the surface of the image carrier is subjected to the next image forming process without removing the transfer residual toner, charging failure such as uneven charging may occur on the surface of the image carrier, or image quality may be deteriorated. It becomes. For this reason, conventionally, a cleaning device is provided at a position facing the surface of the image carrier from the transfer region to the charging region to remove the transfer residual toner. However, when such a cleaning device is used, a waste toner tank that stores transfer residual toner collected from the surface of the image carrier, and a recycled toner that transports the transfer residual toner to reuse the collected transfer residual toner. A space for providing a transport passage is required. This increases the size of the image forming apparatus. In particular, in recent years, there has been a strong demand for increasing the speed of image formation for color images, and so-called tandem type image forming apparatuses having an image carrier for each color are becoming mainstream. In the tandem type image forming apparatus, when the cleaning device as described above is used, it is necessary to separately provide the cleaning device on all of the plurality of image carriers. Therefore, in the tandem type image forming apparatus, the problem of enlargement of the apparatus becomes more remarkable.

  An image forming apparatus that employs a simultaneous development cleaning system in which the transfer residual toner remaining on the surface of the image carrier is collected by a developing device has been proposed as a solution to the problem of such an increase in the size of the image forming apparatus ( Patent Document 1). In this simultaneous development cleaning type image forming apparatus, since the developing device installed for the purpose different from the cleaning of the image carrier is used as the cleaning means, there is no need to provide a separate cleaning device. Therefore, adopting this simultaneous development cleaning method can greatly contribute to the downsizing of the image forming apparatus.

  On the other hand, as a carrier charging device for charging the image carrier, a contact type device that charges the image carrier to a predetermined polarity while being in contact with the surface of the image carrier, and a non-contact type device that is separated from the surface of the image carrier Is known. A typical example of the former contact type carrier charging device is a charging roller, and a typical example of the latter non-contact type carrier charging device is a corona charger. In this case, if a corona charger is used, it is necessary to generate a large amount of discharge in order to bring the image carrier to a desired potential. Therefore, a large amount of discharge products such as ozone and NOx are generated, which is an environmental problem. There is. On the other hand, the use of a contact-type carrier charging device is advantageous in terms of the environment because the amount of discharge generated is smaller than that of the corona charger.

  However, when a contact-type carrier charging device is used in an image forming apparatus of the simultaneous development cleaning system, the transfer residual toner and the carrier charging device are transferred while the transfer residual toner on the image carrier is transported to the development area. Therefore, the transfer residual toner adheres to the carrier charging device, and the adhering transfer residual toner prevents the image carrier from being uniformly charged, and the surface potential of the image carrier is desired. Or a charging failure such as uneven charging may occur. As a result, there is a problem that image density is deteriorated and background stains occur, resulting in image quality deterioration. In order to solve this problem, many proposals have been made so that toner can be prevented from adhering to the carrier charging device and stably charged. For example, in Patent Document 2, a brush-shaped member is brought into contact with the surface of an image carrier after transfer of a toner image, and a voltage is applied to the brush-shaped member so that a transfer residual toner on the image carrier has a normal polarity. There has been proposed an image forming apparatus that is charged so that the transfer residual toner does not adhere to the carrier charging device. However, according to this type of image forming apparatus, since the brush-shaped member comes into contact with the image carrier to which the transfer residual toner is adhered, there is a possibility that the brush-shaped member is contaminated with toner.

Japanese Patent No. 3091323 JP 2001-215799 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to develop development that can prevent transfer residual toner from transferring to a carrier charging device and causing poor charging without the above-described problems. An object is to provide a process cartridge and an image forming apparatus of a simultaneous cleaning system.

  To achieve the above object, the present invention provides an image carrier, a carrier charging device for charging the image carrier to a predetermined polarity while being in contact with the surface of the image carrier, and a charged image carrier. The electrostatic latent image formed by irradiating with the writing light is electrostatically transferred to the electrostatic latent image formed by irradiating the electrostatic latent image with the normal polarity which is the same polarity as the charged polarity of the image carrier. A developing device that visualizes the toner image as a toner image, and collects the transfer residual toner adhering to the surface of the image carrier after the toner image on the image carrier is transferred to a transfer material. The process cartridge includes a toner charging device that applies a charge of normal polarity to the transfer residual toner on the image carrier before reaching the carrier charging device, and the toner charging device is provided from the surface of the image carrier. Process characterized by being spaced apart Suggest cartridges (claim 1).

  The process cartridge according to claim 1, further comprising a light source that irradiates light on the surface of the image carrier, and is transferred by a toner charging device while irradiating the surface of the image carrier with light emitted from the light source. It is advantageous to configure the remaining toner to be charged with a normal polarity (claim 2).

  Furthermore, in the process cartridge according to claim 1 or 2, it is advantageous that the gap between the surface of the image carrier and the toner charging device is set to 10 times or more the diameter of the toner particles (claim 3). .

  In the process cartridge according to any one of claims 1 to 3, it is advantageous to apply a voltage in which an AC voltage is superimposed on a DC voltage to the toner charging device (Claim 4).

  Further, in the process cartridge according to any one of claims 1 to 4, it is advantageous that the toner charging device comprises a toner charging roller (claim 5).

  In order to achieve the above object, the present invention proposes an image forming apparatus comprising the process cartridge according to any one of claims 1 to 6 (claim 6).

  According to the present invention, the transfer residual toner is charged to a normal polarity in a stable state, and the transfer residual toner can be effectively prevented from adhering to the carrier charging device, and a high-quality image can be formed. it can.

  FIG. 1 is a vertical sectional view showing an example of an image forming apparatus capable of forming a full color image. The image forming apparatus shown here is an endless intermediate transfer belt 3 that is wound around a plurality of support rollers 4, 5, 6 and rotated in the direction of arrow A, and is disposed opposite to the intermediate transfer belt 3. The first to fourth process cartridges 7Y, 7C, 7M, and 7BK are provided. Each of the process cartridges 7Y to 7BK has an image carrier 2Y, 2C, 2M, 2BK configured as a drum-shaped photoconductor on which toner images of different colors are formed, and differently on each of the image carriers. Each color toner image is formed and transferred onto the intermediate transfer belt 3 in a superimposed manner. The intermediate transfer belt 3 constitutes an example of a transfer material onto which a toner image formed on the image carrier is transferred. Reference numeral 1 in FIG. 1 denotes the image forming apparatus main body.

  The configuration in which a toner image is formed on each of the image carriers 2Y to 2BK of the first to fourth process cartridges 7Y to 7BK and the toner image is transferred to the intermediate transfer belt 3 is different only in the color of the toner image. Since all are substantially the same, only the configuration in which a toner image is formed on the image carrier 2Y of the first process cartridge 7Y and this is transferred to the intermediate transfer belt 3 will be described.

  FIG. 2 is an enlarged cross-sectional view of the first process cartridge 7Y. The image carrier 2 </ b> Y of the process cartridge 7 </ b> Y shown here is rotatably supported by the unit case 8, and is driven to rotate clockwise by a driving device (not shown) while being in contact with the intermediate transfer belt 3. The image carrier 2Y of this example is formed by forming a photosensitive layer on a relatively thin cylindrical conductive substrate, and further forming a protective layer on the photosensitive layer, and is wound around a plurality of rollers. It is also possible to employ an endless belt-shaped image carrier that is driven to rotate. In either case, it is desirable to use an organic photoreceptor as the image carrier.

  The process cartridge 7Y further includes a charging roller 9 that is rotatably supported by the unit case 8. The charging roller 9 rotates in the direction of the arrow while contacting the surface of the rotating image carrier 2Y. At this time, a charging voltage is applied to the charging roller 9, thereby charging the image carrier 2Y to a predetermined polarity. The In the illustrated example, it is assumed that the image carrier 2Y is negatively charged. More specifically, a DC voltage of −1200 V is applied to the charging roller 9, whereby the surface of the image carrier 2 </ b> Y is uniformly charged to −500 V. As described above, the charging roller 9 constitutes an example of a carrier charging device that charges the image carrier to a predetermined polarity while contacting the surface of the image carrier.

  The charged image carrier 2Y is irradiated with writing light L (light-modulated laser light in the illustrated example) L emitted from the exposure apparatus 10 shown in FIG. 1 which is separate from the process cartridge 7Y. An electrostatic latent image is formed on the image carrier 2Y. The surface potential of the surface of the image carrier irradiated with the writing light, that is, the image portion is, for example, −150V, and the surface potential of the background portion not irradiated with light remains −500V. Instead of the laser type exposure apparatus, an exposure apparatus having an LED array and an imaging means can be used.

  The electrostatic latent image formed on the image carrier 2Y as described above is visualized as a yellow toner image by the developing device 11 shown in FIG. The developing device 11 has a developing case 12 constituted by a part of the unit case 8, and the developing case 12 contains a two-component dry developer D having toner and a carrier. The developing case 12 is provided with two screws 13 and 14 for stirring the developer D and a developing roller 23 that is driven to rotate counterclockwise in FIG. When the developer D is agitated by the screws 13 and 14, the toner is frictionally charged to a normal polarity that is the same polarity as the charging polarity of the image carrier 2Y, and the carrier is frictionally charged to the opposite polarity. The developer is pumped up to the peripheral surface of the developing roller 23 by the action of a magnet (not shown) provided in the developing roller 23, and is carried on the peripheral surface of the developing roller 23 to rotate the developing roller 23. The developer transported in the direction and passed through the doctor blade 24 is transported to the developing area between the developing roller 23 and the image carrier 2Y. At this time, a developing bias of −300 V, for example, is applied to the developing roller 23 by a power source (not shown), and the electrostatic latent image (image portion) formed on the image carrier 2 </ b> Y is placed between the developing roller 23. The negative polarity toner on the developing roller 23 forms an electric field toward the electrostatic latent image. As a result, the toner on the developing roller 23 is electrostatically transferred and attached to the electrostatic latent image formed on the image carrier 2Y. As described above, the developing device 11 applies the normal polarity that is the same polarity as the charged polarity of the image carrier to the electrostatic latent image formed by irradiating the image carrier charged with a predetermined polarity with the writing light. The electrostatically transferred toner is electrostatically transferred to make the electrostatic latent image visible as a toner image. The developer that has passed through the developing region is separated from the developing roller 23 and stirred by the screws 13 and 14. A developing device using a one-component developer having no carrier can also be employed.

  On the other hand, a transfer roller 25 as an example of a transfer device is disposed on the opposite side of the process cartridge 7Y with the intermediate transfer belt 3 interposed therebetween. The transfer roller 25 rotates while being in contact with the intermediate transfer belt 3, and a transfer voltage having a polarity opposite to that of the toner constituting the toner image on the image carrier 2Y (plus polarity in this example) is applied to the transfer roller 25. Is applied, and the toner image on the image carrier 2Y is primarily transferred onto the intermediate transfer belt 3 that is rotationally driven in the direction of arrow A. As described above, the image forming apparatus includes a transfer device that transfers the toner image formed on the image carrier onto a transfer material (an intermediate transfer belt in the illustrated example).

  In the same manner as described above, a cyan toner image, a magenta toner image, and a black toner image are formed on the second to fourth image carriers 2C, 2M, and 2BK shown in FIG. Are sequentially superposed on the intermediate transfer belt 3 to which the yellow toner image has been transferred, and are primarily transferred to form a composite toner image on the intermediate transfer belt 3.

  On the other hand, as shown in FIG. 1, a paper feed cassette 16 containing a recording medium P made of, for example, transfer paper, and a paper feed device 26 having a paper feed roller 15 are arranged in the lower part of the image forming apparatus main body 1. The uppermost recording medium P is sent out in the arrow B direction by the rotation of the paper feed roller 15. The fed recording medium includes a portion of the intermediate transfer belt 3 wound around the support roller 4 by a registration roller pair 17 at a predetermined timing, and a secondary transfer roller 18 which is an example of a transfer device placed on the belt. It is fed during. At this time, a predetermined transfer voltage is applied to the secondary transfer roller 18, whereby the composite toner image on the intermediate transfer belt 3 is secondarily transferred to the recording medium P.

  The recording medium P onto which the composite toner image has been secondarily transferred is further conveyed upward and passes through the fixing device 19, and at this time, the toner image on the recording medium P is fixed by the action of heat and pressure. The recording medium P that has passed through the fixing device 19 is discharged to the paper discharge unit 22 at the top of the image forming apparatus main body 1. Further, the transfer residual toner adhering to the intermediate transfer belt 3 after the toner image transfer is removed by the cleaning device 20.

  By the way, the transfer residual toner adheres to each image carrier after the toner image on each image carrier 2Y to 2BK is transferred to an intermediate transfer member which is an example of a transfer material. In order to remove the transfer residual toner from the image carrier, in the process cartridge of this example, the transfer residual toner attached to the surface of the image carrier after the toner image on the image carrier is transferred to the transfer material is removed. A simultaneous development cleaning system that collects the toner in the developing device is employed. Such a method is employed in any of the process cartridges 7Y to 7BK, and the configuration and operation thereof are substantially the same. Therefore, only the configuration relating to the simultaneous development cleaning method for the first process cartridge 7Y is used here. explain.

The transfer residual toner adhering to the image carrier 2Y after the toner image is transferred to the intermediate transfer belt 3 passes through the charging roller 9 as the image carrier 2Y rotates, and reaches the developing roller 23 of the developing device 11. At this time, the transfer residual toner is electrostatically transferred into the developer carried on the developing roller 23, and the image carrier 2Y is cleaned. At this time, the charge amount of the toner immediately before the transfer of the toner image is, for example, −20 to −30 [μc / g], and most of the charge is charged to the normal polarity, that is, the negative polarity. On the other hand, the charge amount of the transfer residual toner is, for example, about −2 [μc / g] on average, and the transfer residual toner has a polarity opposite to the normal polarity by charge injection or discharge at the time of toner image transfer. Charged toner is also mixed. In FIG. 2, the symbol T ₀ indicates a transfer residual toner charged to a normal polarity, that is, a negative polarity, and the symbol T ₁ indicates a transfer residual toner whose charged polarity is reversed to a positive polarity. ing. Assuming that the transfer residual toner T ₁ whose polarity is reversed in this way reaches the charging roller 9 as it is, the charging roller 9 is applied with a charging voltage having the same negative polarity as the normal polarity. The transfer residual toner T ₁ charged to the electrostatic surface adheres electrostatically to the charging roller 9, thereby impairing the charging function of the charging roller 9.

Therefore, in the process cartridge 7Y of this example, as shown in FIG. 2, the untransferred toner is located downstream of the transfer roller 25 and upstream of the charging roller 9 in the rotational direction of the image carrier 2Y. A toner charging device 30 for controlling the charging polarity of the toner is provided. The toner charging device 30 shown as an example in the figure includes a toner charging roller 31, and the toner charging roller 31 includes a cored bar 32 and an elastic layer 33 integrally laminated on the cored bar 32. Each end in the longitudinal direction of the gold 32 is rotatably supported by the unit case 8. The elastic layer 33 is preferably made of medium resistance hydrin rubber in order to suppress discharge unevenness. The rubber hardness is, for example, about JIS-A 80 degrees, and the diameter of the toner charging roller 31 is, for example, 10 mm. The toner charging roller 31 is separated from the surface of the image carrier 2Y by a slight distance, and the gap G between the toner charging roller 31 and the image carrier 2Y is, for example, 80 to 100 μm, and is 10 times the diameter of the toner particles. It is preferable to secure the above gap G. The gap G can be secured by, for example, attaching a tape having a thickness corresponding to the gap to both ends of the toner charging roller 31 and bringing the tape into contact with the surface of the image carrier. The toner charging roller 31 is driven by the image carrier 2Y or driven by a driving device (not shown) and rotates in the direction indicated by the arrow in FIG. At this time, for example, a voltage obtained by superimposing an AC voltage of 1500 K (amplitude) and a frequency of 2 KHz on a DC voltage of -700 V is applied by the power supply 34. For this reason, the transfer residual toner on the image carrier 2Y before reaching the charging roller 9 is given a charge of normal polarity, that is, negative polarity by the action of discharge, and the transfer residual toner is charged to negative polarity. The Thus the transfer residual toner is negatively charged, it is shown by reference numeral T ₃ in FIG. On the other hand, since the bias of −1200 V, for example, is applied to the charging roller 9 as described above, when the transfer residual toner T ₃ charged to the negative polarity by the toner charging roller 31 reaches the charging roller 9. The toner hardly adheres to the charging roller 9 and passes through the charging roller 9 while being carried on the image carrier 2Y. At this time, the image carrier 2Y is negatively charged by the charging roller 9, and then the surface of the image carrier 2Y is irradiated with the writing light L to form an electrostatic latent image. The latent image is developed by the developing device 11. Although the toner image is visualized as a toner image, the transfer residual toner of negative polarity attached on the image carrier contacts the carrier on the developing roller 23 and receives friction, and the transfer residual toner on the background portion develops. The image carrier 2Y is cleaned by electrostatically transferring into the developer on the roller 23.

  As described above, in the process cartridge of this example or the image forming apparatus having the process cartridge, the transfer residual toner on the image carrier 2Y before reaching the charging roller 9 which is an example of the carrier charging device is regular. Since the toner charging device 30 that imparts a polar charge is included, when the transfer residual toner passes through the charging roller 9 in contact with the surface of the image carrier, the transfer residual toner may adhere to the charging roller 9. Is prevented. For this reason, the charging function of the charging roller 9 is not impaired, and a high-quality image can be formed. In addition, since the toner charging device 30 is positioned away from the surface of the image carrier 2Y, it is possible to prevent the toner charging device 30 from being contaminated with toner and reducing its function.

  Further, when the toner remaining on the image carrier 2Y is charged with a negative polarity by the toner charging device 30, if the image carrier 2Y exhibits insulation properties, the charging efficiency of the toner decreases. Therefore, in the process cartridge of this example, as shown in FIG. 2, a light source 35 for irradiating light is provided on the surface of the image carrier 2Y, and the light emitted from the light source 35 is irradiated on the surface of the image carrier. The resistance of the image carrier is made close to that of the conductor, and the toner charging device 30 is configured to apply a charge of normal polarity to the transfer residual toner. Accordingly, stable discharge can be obtained, the transfer residual toner can be efficiently charged, and the charge amount of the transfer residual toner can be set to, for example, −10 to −25 [μc / g]. In the example shown in FIG. 2, a warm white fluorescent lamp is used as the light source 35, but an appropriate light source can be selected in consideration of the spectral characteristics of the image carrier.

  As described above, when the transfer residual toner is charged with a negative polarity while irradiating the image carrier 2Y to which the transfer residual toner is adhered, the surface potential of the image carrier 2Y is a low potential of −50 V or less, for example. It becomes. For this reason, when the transfer residual toner charged negatively reaches the contact area between the charging roller 9 and the image carrier 2Y, a charging voltage of −1200 V is applied to the charging roller 9, so that it is charged negatively. The transferred residual toner is surely subjected to an electrostatic force toward the image carrier 2 </ b> Y, and therefore the transferred residual toner passes through the contact area without adhering to the charging roller 9. As described above, if the transfer residual toner is negatively charged while irradiating the image carrier 2Y with light, it is possible to more effectively prevent the transfer residual toner from adhering to the charging roller 9.

As described above, the gap G between the image carrier 2Y and the toner charging device 30 is preferably set to 10 times or more the diameter of the toner particles. If the gap G is narrower than this, the transfer residual toner T _{1 that} is positively charged by reversing the charging polarity is electrostatically applied to the toner charging device 30 to which a negative voltage is applied before it is negatively charged. The toner may migrate and adhere to the toner charging device 30. On the other hand, if the gap G is set to 10 times or more of the toner particles, it is possible to effectively prevent the transfer residual toner charged positively from moving to the toner charging device 30 side. Can be negatively charged. In this way, the toner charging device 30 can be used for a long time without being cleaned, and its durability can be improved.

  In the example shown in FIG. 2, a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the toner charging device 30. Also with this configuration, the transfer residual toner charged to a polarity opposite to the normal polarity vibrates in the gap G by the AC component, and is efficiently charged to the normal polarity.

However, even if only a DC voltage is applied to the toner charging device 30, it is possible to make the charged polarity of the transfer residual toner uniform. In the example shown in FIG. 3, a DC voltage of, for example, −2000 V is applied to the toner charging device 30 including the toner charging roller 31 by a DC power source 34A, and light is applied to the surface of the image carrier 2Y by a light source 35A including an LED. The transfer residual toners T ₁ and T ₀ are configured to be imparted with charges of normal polarity. Also with this configuration, the average charge amount of the transfer residual toner can be set to −10 to −25 [μc / g]. The color of the LED needs to be selected in consideration of the spectral characteristics of the image carrier. In general, a red LED is suitable in accordance with the spectral sensitivity characteristics of the image carrier. Further, as described above, by setting the gap G between the image carrier 2Y and the toner charging device 30 to be 10 times or more that of the toner particles, the toner charging device 30 is given a high voltage of −2000 V as described above. Even if it is applied, it is possible to prevent the toner from adhering to the toner charging device.

  Other configurations of the process cartridge 7Y shown in FIG. 3 and the image forming apparatus having the process cartridge 7Y are the same as those shown in FIGS.

  Incidentally, the process cartridge 7Y of this example includes the image carrier 2Y, a carrier charging device including the charging roller 9, the developing device 11, and the toner charging device 30, but at least the image carrier 2Y, A process cartridge can also be configured by the carrier charging device and the toner charging device 30. Further, the plurality of process cartridges 7Y to 7BK, the exposure device 10, the belt cleaning device 20, the intermediate transfer belt 3 and the like are configured as one unit so that they can be attached to and detached from the image forming apparatus main body. It can also be configured.

  Since the image forming apparatus described above has a plurality of image carriers 2Y to 2BK, it is possible to greatly reduce the size of the image forming apparatus by eliminating the dedicated cleaning device for each image carrier. However, the present invention can also be applied to an image forming apparatus of a type that directly transfers a toner image formed on one image carrier made of a photoconductor to a transfer material made of a recording medium.

1 is a partial cross-sectional view illustrating an example of an image forming apparatus. It is an expanded sectional view of a process cartridge. FIG. 3 is a cross-sectional view showing a process cartridge different from the process cartridge shown in FIG. 2.

Explanation of symbols

2Y, 2C, 2M, 2BK Image carrier 7Y, 7C, 7M, 7BK Process cartridge 11 Developing device 30 Toner charging device 31 Toner charging roller 35, 35A Light source G Gap

Claims (6)

The image carrier is formed by irradiating the charged image carrier with writing light, and a carrier charger for charging the image carrier to a predetermined polarity while being in contact with the surface of the image carrier. A developing device that electrostatically transfers toner charged to a normal polarity that is the same polarity as the charged polarity of the image carrier to visualize the electrostatic latent image as a toner image; A process cartridge that collects transfer residual toner adhering to the surface of the image carrier after the toner image on the image carrier is transferred to a transfer material in the developing device; A toner charging device that imparts a charge of normal polarity to the untransferred toner on the previous image carrier, and the toner charging device is located away from the surface of the image carrier. To process cartridge. A light source that irradiates light on the surface of the image carrier, and irradiates the surface of the image carrier with light emitted from the light source, and applies a charge of normal polarity to the transfer residual toner by a toner charging device. 2. The process cartridge according to 1. The process cartridge according to claim 1, wherein a gap between the surface of the image carrier and a toner charging device is set to be 10 times or more the diameter of toner particles. 4. The process cartridge according to claim 1, wherein a voltage obtained by superimposing an AC voltage on a DC voltage is applied to the toner charging device. The process cartridge according to claim 1, wherein the toner charging device includes a toner charging roller. An image forming apparatus comprising the process cartridge according to claim 1.

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